Questions about re-gearing and adding LSD

[olysan]

Good Morning,

I have a 2000 TJ Sahara with the 4.0, 32RH transmission, Dana 30/35 and 3.07 gear ratio. I have added 33" tires and I want to regear to 4.10, and add a LSD in the rear at the same time. This jeep will be used on road 99% of the time and the reason for the LSD is to improve snow/bad weather performance. I've been searching this forum for a while but can't seem to get answers to a few specific questions so here goes:

1. I have access to a set of 4.10 gear axles out of a 2.5L TJ. They look good internally but are very rough externally with rusted and broken brackets. Can I have a shop pull the pinion and carrier from them and install those in my existing axles, or do I need to swap the entire axle? The 2.5L axles would need a lot of reconditioning but if i swapped the entire axle I could do that in the garage.
2. Can I add a Limited Slip type differential in the rear only? Something like a Detroit Truetrac?
3. If i do go to an LSD, does that also include the new gearing or do I have to add something else? Looks like i will still need the correct ring and pinion.

Thanks for your help!
Mike

 

[IAmTodd]

I put a TruTrac in mine when I regeared. So far it seems to work good but I haven't really been on a low traction surface.

 

[Steel City 06]

You can do an LSD in the rear only. A lot of basic 4WD cars include an LSD in the rear and an open differential in the front.

The LSD would be a carrier only, and you will need a ring and pinion of the appropriate ratio for the LSD. Note the carrier break for the Truetrac or other LSD. You will need the one for 3.55 and up.

For the front, you'll either need a new carrier with the gears or "thick" gears, which are designed to work with the standard carriers.

 

[olysan]

Steel City - Thanks! that is exactly the kind of clarity I was looking for.

 

[Brian83]

You can move the gears over but its not recommended. Its not plug and play.They still have to be set up and used gears are harder to set up and most shops wont do it. I would just do new gears and the LSD at the same time in your current axles. And at the point I would look at 4.56 gears and see what the difference in RPMs would be. It may be a better option than 4.10s

 

[BugoutJeep]

If you're swapping an entire axle, I wouldn't worry about using old gears, but I would NOT pull used gears from an axle and use them in a different axle. In industrial applications, I've seen gears swapped around often, but typically just in emergencies and most of the time it's a non-issue, but all of the stuff I see tends to be much slower than automotive applications however they are often used at very high pressures and often see a bit of shock.

4.56 gears would be nicer and honestly with all the work it's not a massive step to just regear, but I've found regearing quotes to be much more than I'd want to pay. If you go with a complete axle, you don't have to change the shims on the pinion and so you only have to get your backlash where it was before (Always confirm backlash and mesh pattern though I've skipped that and still been ok when swapping carriers). You would probably spend some time on the axle before the swap, clean up the rust and weld up the broken stuff, look for a spun tube. I would also do new seals and bearings and probably bushings ie basic maintenance you find.

I like to replace brake lines too and I have been going with stainless lines, but maybe there's some better options around.

If you've got a loose axle in your garage, get some saw horse stands and do everything on your own schedule (unless you've done a lot of reading and watching YouTube, I'd hold off on setting up new gears), then get a hand to swap the axle and you can save some significant money. Axles are pretty easy to deal with and with YouTube, replacing carriers and bearings and seals isn't that difficult, though you almost have to have a few tools to confirm everything is right. I've never done a Dana 30/35 though, but will soon. I think the Dana 44 is similar.

 

[Hopper]

I'm no expert but I would consider new gears. I had same set up 30/35 3:07 and 32rh. I was going to do an auto locker up front and true track in back, but decided to super 35 the rear and auto lock front and rear.
I had rather have a locker up front vs a no slip in the rear if I had to choose. I did 4:10 gears by the way.

 

[olysan]

Thanks guys. You've really helped. I don't ever plan to go above 33" tires. I'm leaning towards 4.1 gears because it keeps my highway RPMs a bit lower and my biggest concern is on-road performance.
I'm starting to think that refurbishing the "extra" axles that I have might be the way to go. I can work on them in the garage at my own pace and maybe save a little money. I am going to reach out to a couple of shops about re-gearing. I think my number is about $1500. If I can get it done for that great, if not I'll probably start working on the "extra" axles.