1999 TJ broken rear pinion gear, re-gear or not

[Deathviper]

Mostly a lurker

I'd been hearing a clunk when putting jeep in gear and I hadn't been able to track it down until now. It appears my rear pinion gear is going out, putting it gear you can see seize and release along with the clunk.

From what I have read and been told (by a mechanic friend) I'm the last person that should attempt changing out gears, he said I would probably be fine up to the point where I need to get the gears matched up.

1999 Jeep TJ Sahara
4.0 - Automatic 150k miles
27 spline 3.07 gear
Tires: 33x10.5
3.5 inch lift
Dana 35 rear, 30 front

I'm mostly driving on the highway to and from work 18 miles each way pretty flat. A little in town here and there. I don't hunt or fish as much anymore and even then it was really abusing it over rocks even then.

Questions:

1) Stay on 27 spline or go to 30? I don't think I'm very hard on it, but its nice to know if I take a trail hunting or fishing I can
2) I don't think I have a need to go the lockers route, I've had her for 25 years without
3) What gears should I go with, mostly highway? I was thinking 4.10 but I'm no expert and would like to be a little educated before I call a shop
4) Is there a better brand to go with for the gears, probably don't need the most expensive but would like quality, assuming a shop would go with what you preferred...
5) How many shop hours should I plan on them charging me for? Just looking for a roundabout number just in case they throw out a ridiculous number

Hopefully that covers it but if I'm overlooking something let me know... I appreciate any feedback!

 

[tworley]

For your use, I think sticking with 27 is fine.

4.10s would put your RPMs roughly at 3k at 70 mph if you stick with 33s. 4.56 wouldn't be bad either. You could try to go cheap and get a set of axles from a 4 cylinder.

I've ran Revolution Gear and Axle, G2 and Yukon with no issues. The RG&A set up easily from my experience. Any set with SKF or Timken bearings would be advisable.

Not sure on shop hours. Anywhere from 8-16 hours for both axles maybe?

 

[Strizzo]

Since you're currently 3.07 and running 33s, it would be a good idea to regear since you're already going to be in the rear axle. You could try to find a used dana 44 so you are getting a better rear axle in the end, but depends on your budget.

I paid around $2,300 for labor to install and set up 5.13s and eaton e lockers in the Dana 44/Dana 30 on mine. This was with me sourcing the gears and lockers myself, and the labor included drilling the housings for the locker wiring, and setting up/installing new chromoly axles, so there was a little extra for dealing with that stuff since I wasn't reusing the old axle shafts.

 

[Deathviper]

Thanks for both of your feedback!

 

[Hopper]

Thanks for both of your feedback!

You have the 32rh transmission in that 99 correct. The 32 does better with the 3.07s than the 42rh. What rear do you have Dana 35 or Dana 44?
I did revolution 4.10s on my 99 sport. Mine was a 35 so I did the super 35 kit with a detroit auto locker.

 

[Woodrow]

...if I'm overlooking something let me know...

One thing. If you can find a stock TJ Dana 35 with 3.07 gears as a take out or junkyard axle, it should be dirt cheap and would be a simple solution since it sounds like your current set up has worked for a long time.

 

[Ashim]

One thing. If you can find a stock TJ Dana 35 with 3.07 gears as a take out or junkyard axle, it should be dirt cheap and would be a simple solution since it sounds like your current set up has worked for a long time.

X2. Just saw one listed on Ohio Jeep Parts FB group the other day for $150. Easy bolt-in and you're back on the road.

 

[Deathviper]

32rh transmission - Yes
Dana 35 - 3.07

I've had it for 24 years or so, I put 33x10.5 tires on it now to long after I got it and a 3.5 lift

I don't really have a problem with the 3.07 but it would be nice to get a little more oomph in it, my reasoning for changing to 4.10 I used to hunt and fish in it, now a days its mostly my daily driver. All the data from everyone is appreciated and gives me some stuff to think about.

 

[hear]

32rh transmission - Yes
Dana 35 - 3.07

I've had it for 24 years or so, I put 33x10.5 tires on it now to long after I got it and a 3.5 lift

I don't really have a problem with the 3.07 but it would be nice to get a little more oomph in it, my reasoning for changing to 4.10 I used to hunt and fish in it, now a days its mostly my daily driver. All the data from everyone is appreciated and gives me some stuff to think about.

I have a 97 auto with 3.55's on 33's, and an 02 5-speed with 4.56's on 33's. Obviously the gearing of the transmssions is different, but not so different that we can't draw a qualitative conclusion. The 4.56 ratio is sooooooooo much more performant than the 3.55. The 3.55 auto combo is a bit of a dog, but if you didn't know any better you'd just think it's how jeeps perform. But if you've ever been in one that is geared better, you quickly realize that better performance is in there somewhere.

The conventional wisdom here is that if you want to run 33's with the auto, 4.10 is probably the best answer. If you think 35's is in your future then 4.56 might be advisable. I'm collecting parts to re-gear my 3.55, and I'm probably going to 35's at some point so I'm planning to do 4.56. Maybe this summer even. Most weeks you can't swing a dead cat without finding a thread on "what ratio should I run?" Read up, check out grimm jeeper's ratio calculator, make an educated decision.

 

[tr21triton]

Have you taken the cover off to confirm its your ring gear ? The spider gears have been known to break. I had to replace mine

 

[MBDIAGMAN]

Triton is right. With mechanical stuff like engines and gear boxes you can do some diagnosis from the outside, but you have to tear down before you accurately know what you’re faced with.

Gearing it for your tire size giving you the same rpm as your original tire size sounds like it would meet your needs.

If you’re still going to trail for outdoor sports, you might consider chromoly axles in front and if the front differential needs replacing use a locker of some sort. In the back, it might be worth an e locker, but definitely a locker in the back.