Just had 4.88 gears installed

0

04RubiOR

TJ Enthusiast
Supporting Member
Joined
Jul 4, 2018
Messages
140
Location
Redmond, OR 97756, USA
Hey Guys,

So I recently bought a 2004 rubicon with a 5 speed. It has 33" tires so I decided to have it re-geared with 4.88's. Picked it up after work and drove it home. About 30 minute drive. When I got close to home, going around a corner I heard the rear end "pop". Drove around to try and reproduce problem. I was in a parking lot doing figure eights at a low speed. It popped 2 more times while turning right. I was going super slow at one point and the rear driver tire started to "slip". Lost traction on asphalt for a second.

Of course the shop was closed when I called to report issue. What could cause this? Back in the early 2000's I had a 91 YJ and I destroyed the spider gears in the rear. That made a similar "pop" to what I'm experiencing on my rubicon. But, with the YJ it made the noise every time I made a right turn and it sounded a lot worse. Any insight would be appreciated. Thanks.
 
How many miles was 30 minutes? When I had my gears done, the shop was adamant about stopping every ten miles to let the new gears cool. I told them my work was only 12 miles from home, and they said to stop at the ten mile mark, and then go.
 
Andy5150 said:
How many miles was 30 minutes? When I had my gears done, the shop was adamant about stopping every ten miles to let the new gears cool. I told them my work was only 12 miles from home, and they said to stop at the ten mile mark, and then go.
Click to expand...
It was 16 miles. The guy said 20 to 30 miles and then let sit for a couple hours. I have the stock rubicon lockers in both diffs.
 
I don't remember if it's a problem on the tj rubi locker but on the JK one, when you reinstall you have to be extra careful of the sensor plunger. If not it gets caught and jams the locker on. Could be something like that.

—
There must have been a time
when we could have said no.
 
  • Like
Reactions: jjvw and 04RubiOR
04RubiOR said:
It was 16 miles. The guy said 20 to 30 miles and then let sit for a couple hours. I have the stock rubicon lockers in both diffs.
Click to expand...
If you have electronic/ pneumatic lockers i dont think you have standard spidergears. I could be really wrong.
 
So after letting it cool down for a couple hours I took it out again and could not replicate the issue. Like before, I just drove it in a church parking lot down the street. It did fine. Could it of just over heated a little bit on the drive home from work?

As far as the spider gear, I was just trying to describe the noise. It reminded me of destroying the spider gears in my yj when I was a 17 year old kid. I'll never forget that noise. And how nervous I was to tell my old man about it. (I was doing something stupid when they grenaded)
 
  • Like
Reactions: Jon Wildes and JMT
I hope you’re good to go! Wish I knew what could have caused that.
 
I would still take it back to the shop and have them reopen it. Just to be sure you didn't chip/break a tooth. Itd better to be safe than sorry. You never know if the guy doing the gears didn't have an off day.
 
Just for clarification, the factory TJ Rubicon rear locker does not use spider gears. It has a Torsen style gear driven limited slip differential, which uses several helical gears in a way I don't fully grasp. These are known to strip and there is no way to repair them.

Hopefully it is just the new ring and pinion.
 
I think I may know what happened, I'll post a photo tomorrow or you can look in my 5.38 gearing thread here in this forum to see what I'm thinking.

There's a pin sensor in the diff housing that detects if the locker is engaged or not. If the installer did know to wedge the sensor open further than normal, the button head of the pin sensor would be wedged on the wrong side of the locker actuator which would push on the locker actuator to partially engage the locker which would make the clunking sound you're hearing.

Look for my photo in the thread that shows a short piece of a red toothpick holding the sensor pin out further than normal so it can slip past the locker's actuator plate to reside on the correct side of the locker actuator when the carrier is inserted. The piece of toothpick has a short length of string or fishing line tied onto it so it can be pulled out once the carrier is in place with the sensor in the correct position.

That's a trick that pretty much has to be used when regearing Rubicon lockers. A regearing tech wouldn't normally know about it unless he asks about it or did a bunch of research on it.

I didn't know about it either until figuring out why the locker was partially engaged after my December regear. Googling the problem/how to regear a Rubicon gave me a clue, my contact at Revolution Gear gave the details on the problem and the toothpick technique they used too.

Look for the thread here, I'll post some pics Friday if they're still needed by the time I can get to it.

Here's one pic showing the sensor with the red toothpick stub holding it fully extended so it can be on the proper side of the locker actuator rim once the carrier is reinstalled. You can see the fishing line I tied to it if you look close.

wvai3ou.jpg


The bottom line is, if I'm correct, your problem was caused by the installer not knowing of the special techniques needed to regear a TJ Rubicon.
 
Last edited:
  • Like
Reactions: 04RubiOR, Chris, Daryl and 1 other person
Thanks for the responses guys. I believe Jerry Drizit are on the right track. One thing i did notice, and forgot to mention, was that i saw the "Rear Axle" light flash on a couple of times like the locker was trying to engage. I suppose that would fall in line with the theory that the installer didn't set the pin sensor correctly. Im just waiting for the shop to open up so i can speak with the installer. Thanks again guys.
 
The sensor button's bottom edge, the part the wooden toothpick is pushing outward in the last photo, is supposed to be behind the ring on the actuator, the ring being the largest diameter part at the very top of this photo.

Carrier-Closeup.jpg

Toothpick-in-Sensor.jpg


I just found the drawing I was looking for that shows its proper position.

When the button is on the wrong side, which it will be if that toothpick technique is not used, the locker will be partially engaged by the sensor pushing against the locker actuator.
Rubicon locker sensor drawing by danb303.jpg
 
  • Like
Reactions: 04RubiOR
I'm dropping it off Tuesday for him to look at it. Talking to him on the phone he seemed perplexed because he installed the gears himself. This shop is supposed to be the bee's knee's when it comes to Jeeps and pretty much anything 4WD, but I'm starting to lose confidence in them.
 
Jerry Bransford said:
The sensor button's bottom edge, the part the wooden toothpick is pushing outward in the last photo, is supposed to be behind the ring on the actuator, the ring being the largest diameter part at the very top of this photo.

View attachment 47268
View attachment 47269

I just found the drawing I was looking for that shows its proper position.

When the button is on the wrong side, which it will be if that toothpick technique is not used, the locker will be partially engaged by the sensor pushing against the locker actuator.
View attachment 47270
Click to expand...
Thanks for that Jerry. Makes perfect since with that drawing.
 
Jerry Bransford said:
The sensor button's bottom edge, the part the wooden toothpick is pushing outward in the last photo, is supposed to be behind the ring on the actuator, the ring being the largest diameter part at the very top of this photo.

View attachment 47268
View attachment 47269

I just found the drawing I was looking for that shows its proper position.

When the button is on the wrong side, which it will be if that toothpick technique is not used, the locker will be partially engaged by the sensor pushing against the locker actuator.
View attachment 47270
Click to expand...
Nice pictures Jerry, that's exactly what I was getting at. I knew the jk rubi locker had that issue I just wasn't sure if the tj one did.

Now that you mentioned the light going on I'd bet good money this is exactly what happened.

—
There must have been a time
when we could have said no.
 
Top Bottom
Back