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General Forums => The Mess Hall => Topic started by: neale_rs on June 22, 2009, 08:34:30 AM
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Looking at a bunch of options this weekend, I think my best options for lower gearing are either swapping in an SM420 or a Tera 4:1. This would be done some time next year.
The 4:1 would give me a crawl ratio of 72:1 and the SM420 would give a crawl ratio of 87:1. Using junkyard parts for the SM420 swap, I think it would cost more than the 4:1, but maybe at the most 50% more. The SM420 would really change the shifting of gears on the street but since I only drive the Jeep for a short distance once a week and about once a month out to a trail (fourth gear most of the way), I think it would be tolerable.
Which would you recommend? Any pitfalls?
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Don't know anything about the SM. I am pretty satisfied with my Tera Low 4:1. Easy to install, doesn't affect driving around town.
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Looking at a bunch of options this weekend, I think my best options for lower gearing are either swapping in an SM420 or a Tera 4:1. This would be done some time next year.
The 4:1 would give me a crawl ratio of 72:1 and the SM420 would give a crawl ratio of 87:1. Using junkyard parts for the SM420 swap, I think it would cost more than the 4:1, but maybe at the most 50% more. The SM420 would really change the shifting of gears on the street but since I only drive the Jeep for a short distance once a week and about once a month out to a trail (fourth gear most of the way), I think it would be tolerable.
Which would you recommend? Any pitfalls?
It really depends on how your Jeep is set up. Do you need 5th gear? Keep in mind that the granny 1st isn't used when on road, so you'll be driving it as a 3-speed. You'll want to rebuild the SM as they were used in commercial vehicles like dump trucks. Also, you might find the SM465 as well since they were the following transmission. Have you located a SM already? I think that is going to be the first task. Then you're going to have to rebuild it. Then locate a Chevy bell housing and have someone mill out a spot for the crank sensor. You'll still need to mix and match for clutch parts as well. Then you'll need an adapter to get it to mate to the NV231. Oh and you'll need to get a new pilot bushing as well as a 23 spline input shaft.
I still say Klune. Or maybe go with the 4to1 and then do a mad rooster or whoever is still making that kit.
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Haven't used fifth for quite a while now.
The Klune + super short SYE is actually pretty hard to justify, an Atlas 4sp is just a bit more expensive and with the short output option I would end up with a longer rear DS than I have now while the Klune + super short SYE would result in a shorter rear DS and just a bit lower crawl ratio. Also, the Atlas 4sp is stronger than the Klune + NP231.
The 4:1 is the lowest cost and easiest to install alternative. That might be the way to go until the AX-5 eventually fails.
What is the mad rooster?
Thanks
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What it comes down to is this, spend 800 bucks and about 4 hours of wrenching and then go wheeling and be happy. Or do a heck of a lot of work end up with an old transmission that yes it works but pretty much miss most of the summer wheeling and spend a lot more money. A lot of these old transmissions don't shift all that great. They are tough though, I rebuilt quite a few sm465's their biggest drawback is that the shift covers/ shift forks can wear really quickly.
U have ran the snot out of my terra low and it has held up great, just don't run it over 10 mph in low range and they seem to hold up just fine. Them little boxes make crawling so much easier.
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That is true, the difference in the cost and work involved is pretty big. I'm leaning towards the Tera 4:1 now.
My Dad has a 1985 2wd Chevy pickup with an SM465, I always liked it, has a good solid feeling.
Thanks
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You say you haven't used 5th gear in a while, are you satisfied with your current axle gear ratio?
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I think 4.56 is good enough. I always had it in the back of mind that a 4 sp tranny would be swapped in eventually so I did not want to need 5th. Any crawl capability now will need to come from tranny or transfer case upgrades. 4.88 might be an option someday if I get 35's.
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That's not very low for a 4banger, and you see no on-road improvement with either the 4:1 or the granny tranny. Improve the axle ratio and you improve both off-road and on-road performance. You could install a pair of d44's with 5.38 for about the same money.
I run 5.38 and the AX5/231 are geared just right for all-around trail use, and can still get out on the interstate and run 65-70 in 5th and even accelerate without downshifting.
To me it just sounds like you're throwing mods at the wrong problem.
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It could be but even 5.38s (a front Dana would be really nice to have) will only get me a 58:1 crawl ratio, better than my current 49:1, but only 18% better. I want something really low, around 50% to 100% lower, low enough not to need a clutch. The Jeep's on-road performance is a non-issue. It gets driven to work once a week, about 5 blocks, just so it gets run at least once a week, and then driven on the highway to a trail about once a month if I'm lucky. The highways here are not high speed interstates, we rarely get over 55 mph and only for short stretches between small towns.
This is a pretty hard decision. Maybe I'll flip a coin and let my budget force me to be happy with whatever gets done!
Thanks
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a 4:1 and 4.56 gears gives close to 80;1 crawl ratio depending on your first gear ratio with my 6 speed and the terra lowmy crawl ratio is 83:1
4.88 will help it a little more 5.38 would be nice for crawling but would suck on the freeway. 4,56 or 4.88 is not bad if the engine has some power mind you the ax5 has a much higher overdrive than the 6 speed trans
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5.38 doesn't suck on the highway, puts my 2.5L in the perfect power band with 35" tires. 33" would be fine.
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5.38 doesn't suck on the highway, puts my 2.5L in the perfect power band with 35" tires. 33" would be fine.
I run 4.88 on mine with 31 tires, and even at 65mph, I am barely reacing 2,500 rpm's, so I think 5.38 and 33's will put you somewhere in the 3,000 rpm range, which is fine for the little 4 banger...
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Thanks to everyone for their comments. It gave me several alternative points of view. I won't actually be changing anything until next year (well, maybe a few small details)...got to save up for a while!
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I agree with the tcase mod. Too much work and not enough benefit from the SM420.
I run 5.13s in my '01 with an AX-5 and 33s. Works out to be about 3000 rpm at 70 mph. About perfect really
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I agree with the tcase mod. Too much work and not enough benefit from the SM420.
I run 5.13s in my '01 with an AX-5 and 33s. Works out to be about 3000 rpm at 70 mph. About perfect really
I used to run 4.88 with 31's (pretty much the same as 33's with 4.88) and it works FANTASTIC! I miss being able to cruise up overpasses on 5th gear now that I put 33's on...
And I agree about the SM420...
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probably the most elegant would be the klune like it's been mentioned before (or the crawl box mod for the 231) since would give you more than 1 low range - but doing that you will also need new driveshafts for front and rear. Not familiar with the SM setup, but probably it is a different length than your current tranny so you might need different driveshafts for that too. the fastest way to do it I would think is still the Terra 4:1 since everything else will remain the same.
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Thanks for the ideas. The Tera 4:1 is definitely the most bang for the buck. I think the Klune is edged out by an Atlas 4 speed, about the same cost and gearing and not as much work.
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I don't know why I keep thinking about it......because my Jeep works just fine as is......lol
but one day I'll probably add a crawl box into the mix. If I do it I plan to leave the transfer case in the stock position and move the engine and transmission forward. I'll need to figure out something for the shifter, though. I'd like it to be in the stock location.
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I don't know why I keep thinking about it......because my Jeep works just fine as is......lol
but one day I'll probably add a crawl box into the mix. If I do it I plan to leave the transfer case in the stock position and move the engine and transmission forward. I'll need to figure out something for the shifter, though. I'd like it to be in the stock location.
You will need to cut a new hole in the floor under the dash and then you can cut and extend the shifter so it comes back to the stock location.
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I don't know why I keep thinking about it......because my Jeep works just fine as is......lol
but one day I'll probably add a crawl box into the mix. If I do it I plan to leave the transfer case in the stock position and move the engine and transmission forward. I'll need to figure out something for the shifter, though. I'd like it to be in the stock location.
That is what I did when I had my Klune installed. It's moved 4 inches forward.
(http://i30.photobucket.com/albums/c331/FourbangerYJ/DSC00132.jpg)
Just a new section of sheetmetal cut to fit. Sheetmetal screws hold it down.
(http://i30.photobucket.com/albums/c331/FourbangerYJ/DSC00135.jpg)
I extended my shifter handle with a coupler nut and a bolt with the head cut off and bent to add length and comfort.
BTW mine was working fine too....now it works better ;)
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Those are some cool shifter knobs!
I´m leaning towards an Atlas II 5:1 at this point. It would give me a 90:1 crawl ratio in first gear and then ratios in second, third, and fourth very similar to my current 1st, 2nd, and 3rd speed 4L ratios. It seems just about perfect for my wheeling.
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Those are some cool shifter knobs!
I´m leaning towards an Atlas II 5:1 at this point. It would give me a 90:1 crawl ratio in first gear and then ratios in second, third, and fourth very similar to my current 1st, 2nd, and 3rd speed 4L ratios. It seems just about perfect for my wheeling.
The 5:1's are nice. Just wondering how much more the 4speeds are. If it's a few hundred more then just get the 4 speed. You will be much happier.
It's not all about the super low crawl ratio's. It's about having choices of crawl ratio's. Like you said you can use the tranny to change ratio's but with a underdrive added. You have that many more choices.
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Amen to that if you spend the coin on an Atlas or stack get a 3 or 4 speed
a 2.73 ratio or there abouts is good for fun wheeling, a 4 or 5 to 1 is great for rock crawling. Actually the cats pyamas would be a box with a 1 tp 1 ratio a 0.8 to 1 ratio a 2.73 ratio and a 5 to 1 ratio that would be about as good as it would get for a 4 banger
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The four speed would be about $600 more for my application (the prices depend on several options). Depending on the gearing option (10.34 low or 5.44), the crawl ratio would be either 185:1 or 97:1. One thing to consider is the driveshaft work that might be required. The 2sp Atlas would require a lengthening the rear DS several inches but the 4sp, depending on the rear output option, could end up either 1 inch shorter or 1 inch longer than what is in the Jeep now. It might be possible to select one or the other and avoid a DS modification, making the actual cost difference a bit less. Lots of variables to consider...
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stak 3 speed, 5.44:1, 3.05:1, and 1:1, and cheaper then the atlas with the same outputs....
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Cheaper but it also has some complications. Something would need to be done to adapt the speed sensor and I would also need to do something about the vaccuum disconect (the cheapest way is a hose clamp and shaft balancing). The Atlas seems more convenient for these details. But these things may turn out to be easy to deal with in which case it would be a good option.
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stak 3 speed, 5.44:1, 3.05:1, and 1:1, and cheaper then the atlas with the same outputs....
never seen one in person but they look really good, i'm with you on this one
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stak 3 speed, 5.44:1, 3.05:1, and 1:1, and cheaper then the atlas with the same outputs....
One of the guy's in the club I run with has one. He has had alot of problems with his. Infact he sent it back to exchange for a new one. He still has issues with it. I'd stay with A Atlas...4speed
The four speed would be about $600 more for my application (the prices depend on several options). Depending on the gearing option (10.34 low or 5.44), the crawl ratio would be either 185:1 or 97:1. One thing to consider is the driveshaft work that might be required. The 2sp Atlas would require a lengthening the rear DS several inches but the 4sp, depending on the rear output option, could end up either 1 inch shorter or 1 inch longer than what is in the Jeep now. It might be possible to select one or the other and avoid a DS modification, making the actual cost difference a bit less. Lots of variables to consider...
Granted $600 is alot of money but look what you get for the extra money. Do the 10.34 not the 5.44 But I would imagine driveshaft mods would need to be made no matter which Atlas you end up with.
The Tera kit is not a bad deal either. Much cheaper, no DS mods.I found that I was either to low or not low enough. But if I had to do it all over again I would not have done a 4:1 in my 231 and just saved up for either the Atlas 4 speed or a Klune and stayed with the 231.
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So go all out with a 4sp Atlas ... :pot:. Well, it would be pretty awsome! I'll have to save up for a bit longer...
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So go all out with a 4sp Atlas ... :pot:. Well, it would be pretty awsome! I'll have to save up for a bit longer...
It's well worth the wait and the extra coin. :thumb:
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what kind of problems with the stak?
my personal favorite is a "black box" + bronco d20
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what kind of problems with the stak?
my personal favorite is a "black box" + bronco d20
what's a black box?
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what kind of problems with the stak?
my personal favorite is a "black box" + bronco d20
It locked up on him when he was on the FWY and it snapped the output on his tranny. The replacement one is having problems staying gear. It keeps popping out.
http://www.northwestfab.com/blackbox.html
The black box is a nice unit. But it lacks a 4:1 option for gears. It's only avail in 2:72 plus it's about 3/4 of an inch longer than the Klune. I do like the Bronco D20. I have had great luck with it! It's a small case but it's fairly strong.
IMO if you run a doubler you should have a fair size split between gear ratio's. The 2:72 and 2:46 is not a wide enough split. I thought about putting in a set of 3:15 gears since the 2.46 are not very good with the small motors we run.
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I do like the Bronco D20. I have had great luck with it! It's a small case but it's fairly strong.
when i was researching and contemplating which t-case to go with it came down to D300 or D20 Bronco (not as easy to find at least at the wreckers i've been to) - anyway, found a D300 and a Bronco with a D20 on it at the same wrecker, i went with D300 even though from what i read the D20 didn't need to be flipped but what was said in a couple of articles was that the D20 had straight cut gears as opposed to the D300 which are helical and that makes it noisy - do you find it noisy at all? i have a hard time imagining how that can cover the noise from the tires and in my case the soft top - i went with the 300 just 'cause i new the case better and i already had rebuild instructions (and the writeups on upgrading the transmission to AX15/NV3550 that i read had a 300 mated to it but from what you say it makes it a nice setup since is already a driver drop). You should post a little writeup on how you did it so it maybe helps the guys deciding which case to buy - i for one would have given it more thought as getting my shifters right took forever.
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http://www.northwestfab.com/blackbox.html
yeah, that's nice and clean.
Couple of things though, they went with only one gear ratio option (2.72:1) so that doesn't really give you a 4 speed setup. And I think is somewhat the same as mad rooster's or dd machine np231 crawler box kit in the end, not sure if these are still available, but if you find one + a 4:1 kit for np231 (i think you can get these) would make it a better setup imho for probably the same money (in case you have a 231 at hand) - with more work however. In my case would bring the driveshaft to about 13'' distance between yokes though, not sure how steep that would make the angle even with the use of CV joint might be a bit messy to setup - any of running short d/s in the rear?
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when i was researching and contemplating which t-case to go with it came down to D300 or D20 Bronco (not as easy to find at least at the wreckers i've been to) - anyway, found a D300 and a Bronco with a D20 on it at the same wrecker, i went with D300 even though from what i read the D20 didn't need to be flipped but what was said in a couple of articles was that the D20 had straight cut gears as opposed to the D300 which are helical and that makes it noisy - do you find it noisy at all? i have a hard time imagining how that can cover the noise from the tires and in my case the soft top - i went with the 300 just 'cause i new the case better and i already had rebuild instructions (and the writeups on upgrading the transmission to AX15/NV3550 that i read had a 300 mated to it but from what you say it makes it a nice setup since is already a driver drop). You should post a little writeup on how you did it so it maybe helps the guys deciding which case to buy - i for one would have given it more thought as getting my shifters right took forever.
I don't find the D20 noisy at all. On the street or trail. In Lo you can hear it but it's not loud. The Klune on the other hand is noisy. The planetaries are loud, just like with the Tera 4:1 231 gears. When the RPM's get around 2K it starts to scream. Anytime you get alot of gear reduction you will get noise. It's normal. The biggest weak link for the D20 is the rear output shaft. It's a 10 spline. There is a couple of upgrades for it. I have not had any problems with mine and have a spare with tailcone incase it breaks.
I did not do the install. I had Four X Doctor in Burbank do it. They also move the drivetrain forward 4 inches. I could of left it in the stock position but since there is room to do it I had it done. I know they took about a day to get the twin stick set up working right. In my build up thread there is some PICS.
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yeah, that's nice and clean.
Couple of things though, they went with only one gear ratio option (2.72:1) so that doesn't really give you a 4 speed setup. And I think is somewhat the same as mad rooster's or dd machine np231 crawler box kit in the end, not sure if these are still available, but if you find one + a 4:1 kit for np231 (i think you can get these) would make it a better setup imho for probably the same money (in case you have a 231 at hand) - with more work however. In my case would bring the driveshaft to about 13'' distance between yokes though, not sure how steep that would make the angle even with the use of CV joint might be a bit messy to setup - any of running short d/s in the rear?
The DD and MR seem to be hit or miss for inventory. They are kinda long I forget the measurement. I would think a XJ/MJ would be A better fit.
The 231 does have a 4:1 avail thru Tera.
IMO leave the stock 2:72 gears in the 231 and add a Klune 4:1. In my club we have seen alot of failures of the Tera 4:1 gear sets. Not sure if its just bad luck or what but there have been about 4-5 people that have had the gears eat themselves due to the welds that hold the planetaries inplace.
Infact my buddy who runs a Klune in front of his 231 took out the Tera stuff and put back the stock stuff when he added the Klune. He has been running this set up for about 5-6 years. It's held up great.
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You will need to cut a new hole in the floor under the dash and then you can cut and extend the shifter so it comes back to the stock location.
That would work with my YJ, but I've already swapped out the 4.0 for a 5.0 and automatic. On my 4-cyl TJ I'd like to keep the stock center console and have the shifter pop up through the stock boot location.
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The DD and MR seem to be hit or miss for inventory. They are kinda long I forget the measurement. I would think a XJ/MJ would be A better fit.
A 231/300 is about the same length as a stock 231, correct?
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A 231/300 is about the same length as a stock 231, correct?
According to Duffy it's + or - 1/4 inch of a stock 231 with slip yoke. I would imagine that the MR is the same since Duffy copied the design.
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Here is an analysis of the Atlas 4sp with 3.8/2.72 ratios that will surprise you:
The lines show the gear ratios you get with 4.56 axle gears and a stock AX5. Line 1 shows the ratios with the Atlas in LO LO (10.34:1), line 2 shows the ratios with the Atlas in 3.8:1, and line 3 shows that ratios with the Atlas in 2.72:1 (like a stock 231). Line 4 shows the ratios with the Atlas in HI HI (1:1). Line 5 shows the ratios you get with a 5:1 Atlas and line 6 shows the ratios you get with a 4:1 LO.
The surprising thing is that even though it seems you will get a lot of forward gearing options (4 Atlas speeds X 4 Tranny speeds = 16) you really only get 11 that are truly distinct (differ by more than 2, e.g. 47:1 and 49:1 are considered the same here). This is being pretty lenient because the ranges overlap quite a bit. To sum it up, it looks like an Atlas 4sp actually only gets you 3 gear ratios lower than the stock setup (68:1, 110:1, and 185:1). The well known ratios like 80:1 and 100:1 are also missing. All in all, it is kind of disappointing although the 3 lower gears may be worth the $ in any case. The 5:1 gets you the 90:1 and some ratios very close to the stock 231 ratios. The 5:1 looks pretty good for the $ difference as long as you don't need even lower gearing than 90:1, and with 4.88 axle gears it would give 96:1 which is pretty close to the 100:1 that is often recommended for serious rock crawling.
(http://i138.photobucket.com/albums/q277/neale_rs/Presentation1.jpg)
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Good points. But I look at it this way. With the 5.0 you get lines 4 and 5. With the 4speed you get lines 1,2,3,and 4. It costs more but you get more. You bring up a good question as to wheather you need the 185:1 or the 110:1. It all depends on what kind of wheeling you do. I know I have never beenable to stall the motor when I was at 188:1. Even on dry pavement in 2LOLO with the brakes on so hard the front tires where skidding. I have stalled on the trail in 2nd gear 4LOLO which was around 115:1.
There is some overlap between the gear choices. But it comes in handy so you don't need to take one box out or put one in to get the ratio you want. To be honest I use the 4:1 the most. When I need more I kick in the 2:46. That combo comes in real handy for alot of things. Once I had it I can't imagine being without.
Personally I think the 4speed would be better with a set of 4.3 and 2.7 gears. I don't know why they don't have that option.
Just a FYI I saw a write up in JP where they put in a 4speed, I think it was a TJ anyway they used the stock front D-shaft (fit just fine without mods) and the rear shaft was in the 17 inch range. The rear one needed to be adjusted.
As far as the $$ the Klune is still a cheaper option. Even if you take off your SYE and get a SS-SYE.
Or just the Tera 4:1 still have some deep gears with that choice.
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That's true, you have to factor in the convenience and strength too. Thanks.
Here is a chart for your setup: 5.38 gears, 4:1 Klune and 2.46 TC. I hope I got those three ratios right.
(http://i138.photobucket.com/albums/q277/neale_rs/FourbangerYJ.jpg)
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That's true, you have to factor in the convenience and strength too. Thanks.
Here is a chart for your setup: 5.38 gears, 4:1 Klune and 2.46 TC. I hope I got those three ratios right.
(http://i138.photobucket.com/albums/q277/neale_rs/FourbangerYJ.jpg)
Ya, you got them right! :thumb:
Help me with this.
1. Both boxes in low
2. Just the 4:1
3. Just the 2.46
4. Both in 1:1
5. ?
6. ?
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5 and 6 are a 5:1 and a 4:1, respectively.
If anybody else wants one I have the spreadsheet ready to go.
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The four speed would be about $600 more for my application (the prices depend on several options). Depending on the gearing option (10.34 low or 5.44), the crawl ratio would be either 185:1 or 97:1. One thing to consider is the driveshaft work that might be required. The 2sp Atlas would require a lengthening the rear DS several inches but the 4sp, depending on the rear output option, could end up either 1 inch shorter or 1 inch longer than what is in the Jeep now. It might be possible to select one or the other and avoid a DS modification, making the actual cost difference a bit less. Lots of variables to consider...
Actually, even with a 2-speed Atlas, you're not assured that the driveshafts will still work either.
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With the 2 speed they would definitely not work. With the 4sp there is a chance but I would have to check the current spline engagement. It sort of looks like it is more in than out so I would go for the short output option and hope for the best. If DS work is needed, it would just have to get done, even if I wouldn't be able to pay the mortgage that month!