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Unread 10-09-2012, 08:17 AM   #1
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1997 TJ Wrangler 
Join Date: Dec 2010
Location: Las Cruces, NM
Posts: 54
3 speed auto, 5.29's and 37's

Did a search last night but nothing really came up. Most of rhe info was manual tranny. Who is running kevlor 37's with 5.29 or 5.38 wih a 3 speed auto? Trying to see what they think of it? Rpms and how it does on higher speeds. Also how safe is it to be in the higher rpms? i have 4.88 and just dosent seem like it has that get up and go. Im running currie hi p-9 and its either 4.88 or 5.29's. 5.13's would of been nice but no go with currie. Thanks for the input.


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Unread 10-09-2012, 08:35 AM   #2
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2004 TJ Wrangler 
Join Date: Feb 2008
Location: Indianapolis
Posts: 19,258
With 4.88's now, you're at about 2900 RPM @ 65mph. With 5.29 gears, you'll be at about 3100. You can easily determine this using any one of the many gear/tire charts available online or simply using what you know:

5.29-4.88 = .41
.41/4.88 = .084 or 8.4%
2900 x 1.084 = 3144 RPM

I'd stick with 4.88's. If you want a slower crawl speed, address the t-case. If you want a peppier Jeep, you'll have to ditch that lethargic 32rh. Your best bet is swapping in an AW4....the OD will allow you to run lower diff gearing (like 5.29 or 5.38) while spinning nice RPM's on the highway, you'll gain a slower crawl speed, and that auto isn't a power-robbing slushbox.
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Unread 10-09-2012, 02:01 PM   #3
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1997 TJ Wrangler 
Join Date: Dec 2010
Location: Las Cruces, NM
Posts: 54
The was the plan, the aw4 I found fell threw. When I bought the front it had 5.29's in it. The rear had 4.88's, I figured I could swap to a aw4 now that my 32rh blew but I'm getting it rebuilt for a run in 2 weeks then sell it when I find a low mile aw4. If any one has on pm please. Hate the way the jeep runs withs the 4.88's. Thanks for the heads up my man!
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