93 YJ with 3:54 front diff and 4:11:1 rear

[J Shafer]

I bought a 93 YJ, Six Cylinder, Std shift, couldn't text the 4WD at the time, engine not running. After getting engine running I tried the 4WD and it bound up. I took the diff covers off and found 3.54s in the front and 4.11.1 in the rear. Questions: 1) What should be in the vehicle? 2) What my best course of action? Thanks, Jeff

Jeff

[Moses Ludel]

J Shafer...The 3.54s (Dana 30 front) were more likely OEM with 3.55 at the rear (Dana 35).  In your vintage YJ, 4.11/4.10 are ratios Jeep used with the 4-cylinder models and a manual transmission. 

If you have oversized tires from 31" to 33", I would go with the 4.10/4.11 range.  Even with stock tire diameters, 3.54:1 is tall gearing.  You have the overdrive 5th gear.  You'll get decent mileage with 4.10s in overdrive and good high range performance.  Off-pavement in low range, the 4.10/4.11 gearing provides a better crawl ratio.  

31" tires and 4.10/4.11 is a good combination.  33" to 35" diameter tires, I'd be considering 4.56:1 at both ends.  What is your planned tire diameter?

Moses

[J Shafer]

Thanks for all the advice, I ordered 3.55 pinon and ring gears, I notice the cluster are shot too, I've never set up a rear end before but I've seen some good dyi videos on YouTube. I have to go find some tools to set the pinon and measure the gear lash.

[Moses Ludel]

You have the Dana 35 rear axle, it's a straightforward build.  A concern when you change ratios with a Dana 35 axle housing is use of the right differential case.  The flange position varies for the difference ring gear thicknesses.  There is usually a break point (ratio wise) that determines which carrier your new 3.55 gear set requires.  Be sure your current carrier will accept the new ring and pinion gears.  Since you have a "hybrid" axle ratio, you need to determine the model year of the axle housing and the correct carrier type for the 3.55 gears.

Pinion depth/height is the primary concern when setting up the axle.  The rest is bearing preloads and ring-and-pinion backlash.  Use a new crush sleeve on the pinion and do not overtighten the preload.  You cannot "back the pinion nut off" to reduce preload.  If you crush the sleeve too much, you must install a new crush sleeve. 

Use a Mopar shop manual as a backup!  You can get a copy (CD or download PDF) of the OEM Mopar Jeep YJ Wrangler Service Manual from a licensed source like Bishko at eBay.  The manual will serve your needs many times over.  I do this kind of work by the book. 

For pinion depth, given that there is a 4.10 or 4.11 gear set in place, installed by who knows, you may need to use a gauge to verify the pinion depth and not guess.  I would run a tooth contact pattern with the current gears before removing them.  If the pattern looks good, the depth markings on the pinion head will be close to specification.  This can make setting up the new pinion gear depth much easier—using the shop manual and pinion markings chart.

Moses

 

 

[J Shafer]

Moses,

Thanks for the advice, very informative and helpful.

Jeff

[Moses Ludel]

You're welcome...You need all the piece necessary for the installation, J Shafer...Keep us posted!

Moses

[J Shafer]

Well I've reached a snag, the lock screw that holds the pinion mate shaft in has a head on it that doesn't fit any tool that I have been able to find. It's round and has a head similar to a star but there are dozens of teeth. Is there a special tool for this? I have an old 35 rear end and I try box wrench, small vice grips, etc. nothing will grab it. 

Jeff

[Moses Ludel]

J Shafer...This should be a male head.  A 12-point box end wrench or 12-point socket of the right size should work.  (The Mopar workshop manual shows the use of a 12-point box end wrench.)  12-point U.S. and metric sockets and box ended wrenches are readily available.

If this is a socket head screw (female like an Allen or hex) and 12-point, that's XZN (German) like my VW Jetta uses.  XZN is triple square or 12-point metric sizing...If you need XZN sockets, I bought a quality Lexivon XZN socket set at Amazon:  https://www.amazon.com/LEXIVON-Triple-Premium-10-Piece-European/dp/B07M6884DY.  Harbor Freight offers this upscale Icon impact socket set:  https://www.harborfreight.com/38-in-drive-professional-triple-square-impact-bit-socket-set-9-piece-59803.html.

Moses