Good morning everyone,

I have a quick question regarding my Jeep’s differential. It’s a 2016 JKU 75th Anniversary Edition with a 5 speed automatic transmission. I’m running 33’s with the 3.21 gear ratio. It’s not an absolute dog around town on relatively level ground, but if you hit a hill of any size it certainly takes the wind out of its sails. If I’m pulling my utility trailer ever more so, plus a lot off down shifting. It has been recalibrated for the change in tire size. So, to remedy this I ordered a 4.56 gear set. I do 80% of my driving in town and most trips out of town are less than 75-125 miles round trip. I really was planning to go 4.11, but after a LOT of forum research decided on the 4.56’s. My next tires will probably be 305 or 315, not sure yet. Anyway, to my question. I am thinking about going ahead and putting a TruTrack in while it’s opened up. I have the dreaded popping occasionally from a start and the dealership says nothing is wrong. From my research it appears that the LSD is likely the culprit. (Everything underneath is torqued to spec.) I hate to spend the extra money, but I am just worn down with this popping sound! Is installing the TT a simple matter of replacing the old LSD with the TT since the old LSD will already be out? I don’t do anything like what most of you guys do with your Jeep’s. Mine is a DD and I only put about 3500 miles a year on it so the TT May be overkill.
Any advice would be greatly appreciated!

 

Yes, the current LSD is the actual carrier that the ring gear is bolted to. The new TT would simply become the new carrier and since you are regearing anyhow it is no extra work using the new TT vs the old.

 

Thanks reshape! That’s what I was hoping to hear!

DJ

 

If you are going 35's I would suggest a rethink of the gear ratio to 4.88.

 

Could you provide a little more info on the popping? Just a sound, or is it felt as well? I am curious what the folks you read posts from have said is actually causing it (which part of the LSD do they indicate is making the noise). Have you (or did the dealership) opened up the diff and actually looked inside to verify that the unit is intact with no loose bolts or anything sitting at the bottom? Not sure how the clutches are put together, but maybe something to do with that?

Are you putting a truetrac up front also? That D30 will need a new open carrier ($125-ish last I looked) when swapping to any ratio beyond the current 3.21, so maybe it's worth considering the options. See how easy it is for us to spend your money for you...

 

Well, it only happens when I accelerate. Just this past Friday we took a trip out of town and for the first 30 miles or so not a sound. Then, I stopped at an intersection and as I pull away, there it was...POP, sometimes it’s two, never more.
Its been to the dealer twice. The first time they drove it the tech said that he couldn’t hear anything and, to his credit he ask me to drive him around to see if we could replicate the noise. I got in, put it in reverse and backed out of the parking space. I put it in Drive and as we rolled forward, not 10 feet, there it was. The tech said that it was “definitely in the rear end”. The service manager told me that they would have to reschedule it since it could be with them a while. When I took it back they opened the rear end and said that everything looked fine, that they could not replicate the noise. Nothing was in the rear fluid, no chunks, gear teeth or the like. It was there a solid week. I like the folks at the dealership, but I just don’t know what to think about the service department now. When all this was going on I was under warranty it has since expired. I did a lot of research here and on the Wrangler forum and it seems that everyone who had the same issue, and there were many, that replacing the LSD solved the issue. I’m taking it to an independent shop for a regear on the 11th. I’m going to talk to the shop tomorrow about replacing the LSD when they regear it. Oh, and I’ve never heard it traveling. It’s always as I pull off from a dead stop and it seems more noticeable when several miles have been driven. My Jeep only has about 43,000 on it, so I wouldn’t think the LSD clutches would be worn out. That said, I did not purchase it new but it obviously had not been abused. It was a lease that had been turned in and every service was done by the dealership that sold it. This is all documented.
Hope this helps. I just know I’m tired of trying to figure it out!

 

I can't tell you the sound is or isn't the LSD, but I've seen more than 1 or 2 people report their factory clutch packs were kaput before 50k miles believe it or not.

 

Yes, I've heard that too. That's why I was considering changing to a TrueTrac or Dura Grip while it was in the shop. I hate to spend the money to rebuild the old unit if its going to be shot in less than 50,000 miles.

 

Jeep’s in the shop now! I decided to go with the 4.56’s and Detroit TrueTrac. Can’t wait to get it back and drive it, especially with the trailer behind it.

 

Picked up my Jeep from the shop Thursday afternoon and I am loving the 4.56’s! I’m going through the gear break in phase now, following Yukon’s directions to the letter! The TrueTrac is super quiet. As I said, I’m in the break in period for the gears so I’m not doing anything aggressive, but the difference in the response is amazing! I have a trip next weekend that will include some interstate driving and that should get my break in miles behind me, plus it will give me an opportunity to check the impact on my MPG’s.