Topic: Atlas Dilemma

[Jeffy]

2'' is massive if you put that in perspective with an 18 or 20'' driveshaft, but without a doubler is really not necessary (i would love a super short output but the Novak with VSS is like $6 or 700).

Well to put that into perspective if they could put the yoke flush with the case like on the front I think you could gain another 2".

[sharpxmen]

Well to put that into perspective if they could put the yoke flush with the case like on the front I think you could gain another 2".

you can get a flat yoke but the CV would be that much longer so really no gain there

[sharpxmen]

now that i think about it - there is a CV super short yoke you can get for the large output shaft, i think from JB or novak, you're right, the regular ones are probably 1'' longer than the short one.

[aw12345]

CV with a drive flange would give a bit more room doesn't it? Also they allow steeper driveline angle. Supershort SYE on the Atlas and the converter box for the speedo ought to do the trick also. Also pretty sure the Atlas is shorter than a NP231

[neale_rs]

With the 2 speed atlas you will gain a lot of rear driveshaft length, no need to do anything special.  The front driveshaft will be several inches shorter.  With the 4 speed atlas you lose about 2 inches of rear driveshaft and the front changes only a bit (not sure which way though).  It works fine though in practice.

[VA_YJ]

Here's a TC length chart that I put together when making my decision:

Atlas 2 Short Tail      11.8
Dana 300 (stock)      12
Atlas 2 Long Tail      13.8
Atlas 4 Short Tail      15
NP 241 OR (stock)      15.25
NP 231J SYE      16 to 17
Atlas 4 Long      17
NP 231J (stock)      20.5 to 21

All dimensions in inches.  I don't have the GM VSS options listed.  The Atlas 4 speed with the long tail is about the same as a 231J with an SYE.

[sharpxmen]

CV with a drive flange would give a bit more room doesn't it?

i thought it comes to the same length or very close (maybe 1/2'' diff to the center of the first u-joint on the CV) - i didn't measure as i never had a flange type CV but this is from looking at pics when i was researching for the increase length with the crawl box - seems that whatever you gain with the flat one is actually needed on the CV side to hold the u-joint.

[neale_rs]

Here's a TC length chart that I put together when making my decision:

Atlas 2 Short Tail      11.8
Dana 300 (stock)      12
Atlas 2 Long Tail      13.8
Atlas 4 Short Tail      15
NP 241 OR (stock)      15.25
NP 231J SYE      16 to 17
Atlas 4 Long      17
NP 231J (stock)      20.5 to 21

All dimensions in inches.  I don't have the GM VSS options listed.  The Atlas 4 speed with the long tail is about the same as a 231J with an SYE.

For the Atlas 4 speed, those dimensions are from before the redesign, it is longer now by about 2 inches.

[stan98tj]

Are you set in buying an Atlas?
I was on the phone wih them when I was considering t-case options and when I got off the phone, I felt like it was just too much, a bit overkill. When I asked them for the pros to running one, the reliability/durability was def a plus, given it is gear driven. However, when I asked him what the advantages were and the typical uses off road, the image I kept getting was of buggies on 40s with spool lockers using the selectability of the axles in order to dig around or swing around tight spots. I'm not sure what your end plan is for  the Jeep, but I felt that the Atlas was a bit overkill for most wheelers.

[Jeffy]

Are you set in buying an Atlas?
I was on the phone wih them when I was considering t-case options and when I got off the phone, I felt like it was just too much, a bit overkill. When I asked them for the pros to running one, the reliability/durability was def a plus, given it is gear driven. However, when I asked him what the advantages were and the typical uses off road, the image I kept getting was of buggies on 40s with spool lockers using the selectability of the axles in order to dig around or swing around tight spots. I'm not sure what your end plan is for  the Jeep, but I felt that the Atlas was a bit overkill for most wheelers.

I've been down the road of incremental upgrades and after a while you would rather spend the money once and go overkill and never had to worry about it again.  Like I've mentioned many times before I've held off on spending any money on the NP231 (it was NP before they changed it to NVG).  I've had the Jeep for 21 years so it's going to be a good investment.

I'm pretty much set on the Atlas II at this point.  Just need to gather the funds and order which will hopefully be later this year.

[sharpxmen]

Dana 300 4:1 is also a good choice but unless you find one second hand with the cost of the gears and rebuild kit would get expensive as well. The advantage with the Atlas offroad (and that's to also answer a question that was posted) is that it has syncros so you can shift on the fly, not the same with the D300 and that is a big plus not having to stop to change from low to high or high to low. there's also the twin stick matter which gives you the 2wd low and front digs (although that can damage the front axles but it's there if you're in a bind).

[jfrabat]

The advantage with the Atlas offroad (and that's to also answer a question that was posted) is that it has syncros so you can shift on the fly, not the same with the D300 and that is a big plus not having to stop to change from low to high or high to low.

That I did not know, but I wonder how usefull that REALLY is.  I mean, assuming you went with low gearing to have 10 disctinct gears, when you hit 5th low, you need to step on the clutch, and go to 1st and shift also to low (two shifts at once), so that would make it a bit too complicated to be useful (at least for me, and my style of wheeling, anyway)

[sharpxmen]

is not to shift 10 speeds in sequence, is for example you come out of a hillclimb and need to resume speed at least in 2nd or 3rd with no reason to have the engine screaming or 5th and low you can go back to 2nd and hi without having to come to a complete stop, same with approaching a steep climb.
also, imagine this, you come up to an unexpected downhill, would be nice to use engine brake in lo (being able to shift into it), sometimes it's dangerous to attempt to get to a full stop

[neale_rs]

It's true you don't have to come to a complete stop but the synchros are hard and only allow the down shift when going really slow (probably slower the lower geared it is, 5:1 slower than 3.8:1).  You put in the clutch and then hold the lever there as the vehicle loses speed.  Then at some point you are going slow enough and it just slides into gear, at higher speeds it is almost impossible to shift (which is good because shifting into low at speed could snap something or eject passengers out the front window).  It is very nice though that it doesn't grind the gears.

[sharpxmen]

yeah, can't do that with my D300, you can shift at very low speed or if you're skilled enough to match the speeds but always grinds.