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4.88, 4-1 T-case, and AW4....Too low????

D

Deadman 94 xj

NAXJA Forum User
Location
Pittsburgh, PA
Just trying to figure out my transfer case options. 4.88's and an auto would be a bit of overkill with a 4-1 t-case would it not?

33-35" tires btw.

Thanks for any help
 
If the axles can handle the increased torque and you prefer rockcrawling, it'll be fine. If the axles are stock, you might want to upgrade them. For general wheeling and mud, that's an awful lot of crawl ratio. You'll be winding your engine rpm up something fierce to spin those in the mud.
 
Axles are an 8.8 rear with a detroit and a beefed up D30(lol) open. Nothing extreme. I like to hit hill climbs and rocks. I try to avoid mud as much as I can.

also, they're both trussed if it matters much.
 
Last edited:
That is actually a decent crawl ratio. 4.88 AW-4 and 4:1 puts you in the 55:1 range. It will be too low for the fire roads and the easy blue level trails, might make you the slow guy, but for higher blues and blacks it will be good. If you are open in the front, shouldn't bother the D30 too much either.
The 8.8 will handle it fine.


I run 57:1 for most all trails and run 1:1 (tcase) for the fire roads and green trails.

For the technical trails and high black & reds I use all the gears available.
 
I put an atlas 4.3 into a buddy's XJ with 4.56's and 33's - and it was about perfect... Pleanty of ratio, but not so much that you couldnt drive out of anything...

when I sell my teralow, im going to sell it to a friend with 4.88's, aw4, d30/d44... he is already planning on having it... :D

I love my teralow, and do NOT think it would gear you 'too low' :D
 
Thanks for the replies. From what I was able to research, 55:1 does seem like a good ratio.

If I were ever able to aford the Atlas, I know they have a few different ratios as well.
Is there a good online calculator to figure out crawl ratio?
 
Last edited:
Tranny gear ratio X T-case ratio x ring and Pinion ratio.

AW-4 first gear = 2.82
T-Case = 4:1
R&P = 4.88

2.82x4x4.88 = 55.05:1
 
Deadman 94 xj said:
Thanks for the replies. From what I was able to research, 55:1 does seem like a good ratio.

If I were ever able to aford the Atlas, I know they have a few different ratios as well.
Is there a good online calculator to figure out crawl ratio?
Click to expand...

have MS Excell?

crawl ratio is just "Tranny first gear" X "transfercase low" X "diff gears"

some argue that the torque converter can be multiplied in at 1.5 because of the reduction it offers before stall...

My crawl ratio is:
AX-15 - 3.8
Teralow - 4
Diffs - 5.13

3.8*4*5.13=~78:1

Im going to get an atlas 5:1 eventually -
3.8*5*5.13=~97.5:1

the best part about gearing low - is that all you have to do when you think *damn, i geared too low* is pull your head outta your ass, and shift up a gear :D
 
As an aside, have you thought about the Teralow kit? It's an easy way to maximize your crawl ratio and to help minimize stress on other components. The way I like to think of it is if you go slower, you can keep your rig under control and reduce the risk of breakage... which is inevitable
 
The thing with automatic is, with the torque converter slipping, the gear ratio is actually lower than 2.82 because the TCC is not locked up when you're crawling along. I don't know how you could ever determine the ratio tho, its always changing with the rpm.
 
Deadman 94 xj said:
Just trying to figure out my transfer case options. 4.88's and an auto would be a bit of overkill with a 4-1 t-case would it not?

33-35" tires btw.

Thanks for any help
Click to expand...

Thats what I run with 35"s. Its great.
 
XJ_ranger said:
the best part about gearing low - is that all you have to do when you think *damn, i geared too low* is pull your head outta your ass, and shift up a gear :D
Click to expand...

Exactly. Just shift up to 3.

I run 5.13 gears, AW4, and 4:1 tcase, with 37's. I run the auto in 3 most of the time, drop down to 1 when I need to crawl over an obstacle. Works just fine.
 
igotanxj said:
The thing with automatic is, with the torque converter slipping, the gear ratio is actually lower than 2.82 because the TCC is not locked up when you're crawling along. I don't know how you could ever determine the ratio tho, its always changing with the rpm.
Click to expand...

AWshifting.com???
 
DaffyXJ said:
Tranny gear ratio X T-case ratio x ring and Pinion ratio.

AW-4 first gear = 2.82
T-Case = 4:1
R&P = 4.88

2.82x4x4.88 = 55.05:1
Click to expand...
not tring to start no bull DaffyXJ but this is what I found out on the AW4 tranny AW4 - 2.804 1.531 1.000 0.753(OD) 2.393(rev)
 
JabosXJ said:
not tring to start no bull DaffyXJ but this is what I found out on the AW4 tranny AW4 - 2.804 1.531 1.000 0.753(OD) 2.393(rev)
Click to expand...

Yeah, I found 2.80; 2.804 and 2.802 on the web as well. All reasulting in a worst case difference of .31232 difference in the computed crawl ratio.

ooppps!! My Bad.
 
Atlas 3.8
4.88
AW4
35 MTR
This is what I run and seems perfect for me.
 
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