Topic: 31 MTs with stock gearing

[Jeffy]

I drove a friends Jeep with 31's and stock gears and this was after driving mine with 32's and stock gears.  His felt downright peppy while mine felt slow and slug-ish.  Then we swapped mine to 4.56's and it was damn quick compared to his.

I think 31's are good on a 2.5L with stock gears.  Actually I think it's better then good as you should be able to do most trails with this setup.  The only other consideration would be to go with 33x9.5 or 33x10.5's if you wanted larger without having the increase in weight and rolling resistance.

[aka-justin]

Why does it say when I try to send someone a PM by clicking on their name that "many apologies, but you cant view just and profile"
What the hell is that about? Since when?
Anyway, I was wondering how you got a bigger (I'm assuming you got the 4.0 TB) throttle body for 20 bucks 1995yj? Sorry if this is off topic, I tried to PM you but the above happened.

Craigslist baby. $20 for a TJ 4.0L Throttle Body and the guy threw in his Air Cleaner and Stock tube.  I was like  "Sure.  Thanks!"

Looks like this kinda, minus the K&N

BTW, I have some better low end power when I said hill climbing and mud.  Didn't mean crawling in the mud.   That's what you do when you attempt to go slow or too stupid in it.  Been there, crawled on my hands and knees out of that. (Not yet in my jeep, but there's always a first for everything I guess.) 

[jcsanders79]

I'm not saying that it won't take some abuse. but it could also be luck. plus if it's not rated that heavy your risking breakdown. and if your like me and run miles back in the bush for a run you don't want to blow a axle. or even risk it. I have lots of buddy here with stock axles running 35's to 38's. and I have seen them shear mounting brackets completely off and do gear and axle damage shear spines or even split cases . if your willing to pay the tow bill vs just building it stronger or not exceeding the max suggesting your running the risk of failure components.

I wouldn't feel too safe with 33's and the D-35.  Having the 4 banger helps be easy on it but 33's are notorious for assiting in the snapping of D-35 axle shafts.  I had always heard up to 35" tires for the D-30 though?  Either way it is WAY tougher than the D-35.

[Torch_Ind]

I wouldn't feel too safe with 33's and the D-35.  Having the 4 banger helps be easy on it but 33's are notorious for assiting in the snapping of D-35 axle shafts.  I had always heard up to 35" tires for the D-30 though?  Either way it is WAY tougher than the D-35.

http://www.greatlakes4x4.com/showthread.php?t=57

[Torch_Ind]

Axle Style                Maximum Tire Diameter
Chrysler 8.25            33 inches
Dana 30                  32 inches
Dana M35                33 inches
Dana M20                35 inches
Dana 44                  34 inches
Ford 8.8                  35 inches
GM 8.5                    35 inches
Toyota 8                  34 inches

this came off my installation instructions of my 4.88's yukon gears I just bought!!

[aw12345]

The dana 30 in a TJ does pretty darn well with 35" tires lot of peeps here in So Cali run that way on rocks and do quite well with it

[Torch_Ind]

ya well I'm not saying it's not going to work. I'm just saying your drastically reducing it's life span.  TJ's aren't very old yet give it till it's the age of a YJ & CJ.

[Torch_Ind]

also want to add TJ have a optional axles Dana 44's with/without lockers

[Torch_Ind]

if you want fully dependable axles with over 33's. I would recommend finding full floating axles

[aw12345]

Chris the weakest part on a YJ dana 30 is the 2 piece axle shaft and the smaller u joints.
swap those for some TJ shafts with spicer 760 u joints and wheel it. Granted it still will not acommodate 5.13 gears but other than that lots of people using a Dana 30 hard in YJ's as well as TJ's

[Torch_Ind]

sorry I think the topic has gotten off topic lol. 31x10.5's or narrower. with stock gearing as long as your diff came 4.11 with the 4cld. any bigger your going to want to re-gear. any bigger then 33's I personally recommend at least going to dana 44's .

hope that helps

[jcsanders79]

I run 33X10.50's got a D-44 rear and D-30 front (currently collecting parts to put in a D-44) with 4.88's and Aussie F&R and it's a great improvement over stock.  However, I'm planning on putting the D-44 up front so 1) I won't be wasting $ on an OX locker if I ever want to go bigger on the engine 2) 4WD HIGH needs a little more umph (got a Tera Low 4:1) it does ok but when it getts slick (expecially on a hill climb) the gearing is not low enough in HIGH and to low in LOW.  5.13 or 5.38 would be my optimal gearing.

If you think the D-35 is ok for 35" tires and the D-30 is not you should look into the # of D-35 breaks vs. D-30 breaks.

[Torch_Ind]

I run 33X10.50's got a D-44 rear and D-30 front (currently collecting parts to put in a D-44) with 4.88's and Aussie F&R and it's a great improvement over stock.  However, I'm planning on putting the D-44 up front so 1) I won't be wasting $ on an OX locker if I ever want to go bigger on the engine 2) 4WD HIGH needs a little more umph (got a Tera Low 4:1) it does ok but when it getts slick (expecially on a hill climb) the gearing is not low enough in HIGH and to low in LOW.  5.13 or 5.38 would be my optimal gearing.

If you think the D-35 is ok for 35" tires and the D-30 is not you should look into the # of D-35 breaks vs. D-30 breaks.

you can't get gearing in the d30 bigger then 4.88's & it's I don't see many rear diff's being d30's and to compare d35's breaking when there the diff most used being in the rear vs the d30 that's only used in 4x4. that's a unfair comparison.  the d30 is tested and rated lower then the d35 how is that not enough to go by?

[aw12345]

D30 will still be going when the D35 spit parts all over the trail. A bunck of us run rocky trails almost every weekend most of us use 35's most of them have a d44 in the rear and a d30 up front works just fine for pretty hard wheeling. Love my Terralow but agree that the step between low and high is to big. A 3 speed atlas or stack would be the ticket

[jcsanders79]

Your CHART is wrong.  Google it.  The D-35 WILL break well before the D-30.  If you've spent any time on difficult trails with Jeeps that have a D-35 you'd know that.  As for the rear only giving out in when in 4x4 see previous sentence (ie if its difficult you'd be in 4x4).  Maybe you've got the the number associated to the axle confused with axle size?  D-35 doesn't stand for 35" tire.  Obviously not done much research on the D-35.  Oh, I know that the D-30 is capped at 4.88 thats why I mentioned collecting parts for the D-44?  To have done as much mechanical work as you claim in other posts your laggin!