Blown front locker!

[Jordan345]

Well I didn't think this could happen, especially for a locked front diff. I had just finished doing the switch mod to operate my lockers and took the cruiser out to test if they did in fact work independently; I was driving on a gravel road, covered with light snow - pressed on the gas to get a little spin going and dreaded grinding ensued. I was about 200 meters home and limbed back (Center diff was locked) at 2 kmh. It was -20 and my tools were on my shop floor.

Got home and pulled the front driveshaft and the splines, and toon it down to my friends with a hoist. No apparent damage below, but pulled the drain bolt and drained the diff fluid. Magnet was covered in shavings. I will be opening the diff later today.

Locker was just installed a month ago. I did not regear.

Very disappointed and unsure if manufacturer problem, install problem or else. This is a tjm pro locker, purchased at just differentials.

Anybody else have this or heard of this problem?


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[jgray]

Who installed the new locker? Did you just move the old ring gear from your old diff to the new TJM carrier? Have you pulled the diff inspection cover yet? Based on your driving condition description it sounds unlikely you would damage a brand new locker that way. Who set everything up for you? I'm leaning towards install problem if in fact it is the diff...

 

[ENGINE er]

Sounds like an install issue, not a locker issue.

 

[Jordan345]

Photos show shock loading of ring and pinion. Causes- well, was the backlash set correctly? I don't know. Environmental conditions were extreme cold and resulting gear oil likely not warm ( thick). Front locker may not have engaged all the way, if that is possible.

Locker was in great shape! Just ring and pinion were buggered. Called just differentials and they have a replacement in the mail already.


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[spressomon]

Just a guess but...maybe carrier bearing preload was too light?

 

[bamabrock]

I think 35" tires on a vehicle this heavy is pushing the limits for the front gears, assuming they were properly installed. I guess you could try to have the set chryoed to increase strength.

 

[Jordan345]

We'll go over preload and back lashing to get the next set in right. I appreciate the ideas.

I also see no correlation to 35's, mass and limits to front gearing. The cruiser isn't that heavy - 6000 lbs. lots of heavier rigs out there with similar setups. I think for a 100, I am a fairly light 'loaded' rig. I am no expert on driveline setups, so you may have a point. I just have never heard of another 100 with this problem.


Out of curiosity, I have been told contradictory points- does the cruiser have to be stationary before locking air lockers or can it be moving ? I have always stopped it, but would like to get some fact.


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[sleeoffroad]

If I read your first post right, you modified the wiring to be able to lock the front only?

If so, I would never recommend or even suggest someone do that on a 100 with an already small vulnerable diff.

 

[yotasavg]

Sorry to hear about the damage Jordan, glad it's getting fixed up though.

Christo, why would having the rear diff locked as well make any difference in the front diff being locked? I could see in a technical situation how the rear would take stress off the front, but in Jordan's description he wasn't even doing anything but rolling. Your post seems to suggest that if the rear was also locked he would not have experienced this outcome.

 

[sleeoffroad]

In this case it probably did not. However in an off-road situation you would rather have the rear diff "push" the truck than the front diff "pull" the truck out of a situation.

 

[yotasavg]

In this case it probably did not. However in an off-road situation you would rather have the rear diff "push" the truck than the front diff "pull" the truck out of a situation.

Thanks for confirming! I wasn't sure if you were getting at something else, I completely agree though.

 

[paflytyer]

Sorry to see this Jordan. Did you set the gears/locker up yourself?

 

[Jordan345]

If I read your first post right, you modified the wiring to be able to lock the front only?

If so, I would never recommend or even suggest someone do that on a 100 with an already small vulnerable diff.

No Christo, I modified the wiring harness to allow independent operation of both lockers. The stock installation only allowed the rear to lock if the front was locked. I could lock the front, both, but not the rear independently. The mod allowed me to have only rear locked in many cases with the open front end. I followed the instructions for the mod which are fairly well known.

I was surprised that the stock wiring was configured the way it was. To me it was backwards but I followed the instructions to a 't'.




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[Jordan345]

Sorry to see this Jordan. Did you set the gears/locker up yourself?

I didn't set the gears or do the install, rather a custom off-road fabricator/mechanic local did the work.


I still haven't seen anyone comment on needing to stop completely to engage diff locks. What's the verdict?

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[Fast Eddy]

I still haven't seen anyone comment on needing to stop completely to engage diff locks. What's the verdict?

The only time you'd want to "stop" is if you were stuck and only one side was spinning. It's also not a great idea to do it in a tight turn. Normally when you're driving, you could lock the lockers almost any time as both sides are turning about the same speed.

 

[spressomon]

I normally lock the ARB under 10-15mph and with very light accelerator if any; locks/unlocks very quickly on mine...

Although I haven't purposely tried to destroy the front diff...I haven't babied it either; most often used front only. I've had it and used it in some fairly tough condition/trails/ledges/rock piles...since installing it in 2006 I've put on +120k miles without issue.

Hopefully I didn't just jinx myself

 

[paflytyer]

I also routinely engage the front while moving forward slowly. I bet less than 10mph every time.

 

[r2m]

I have the same TJM locker that I purchased from Carl at Just Diff's, I do run 35" (BFG M/T's) also. The difference may be that when I installed the front locker, I also re-geared the front and rear diff's and re-geared the transfer case (Marlin Crawler gear set) and I had it installed locally.
I have not had the time to do any difficult wheeling because of time and I haven't any armor on it yet (read: no front or rear bumper or sliders) so I'm real careful where I try out the lockers. When I have, everything has worked like a charm. I installed the ARB compressor, wiring myself using the factory 80 series front/rear locker dial switch to replace my factory rear e-locker dial switch (I have a 98 LC). I had professionals do the front locker and just plug the hose into the compressor manifold and do all the other gearing.

As a note, when I received by LC back, I was told to be easy on it for a 1000 miles, not go over 65mph or any hot rod starts so as to work the gears in. Maybe you should have done that. Just a suggestion...

But as you noted, it could have been the extreme cold. Down here in sunny So Cal, I don't think I'd ever have an issues of having to warm up my fluids before stepping on it.

 

[SanDiegoCruiser]

I just went through the break in period for my ARB diff & regear. 500 miles of easy driving. Then both diffs were drained and replaced with new fluid. The only thing I noticed is the steering is a little stiffer/tighter than before the regear. Is this normal? When I mKe a sharp turn, I can let the wheel release and it will spin back to center...

 

[paflytyer]

I just went through the break in period for my ARB diff & regear. 500 miles of easy driving. Then both diffs were drained and replaced with new fluid. The only thing I noticed is the steering is a little stiffer/tighter than before the regear. Is this normal? When I mKe a sharp turn, I can let the wheel release and it will spin back to center...

If you mean when the front is locked, that's very normal. It should be almost hard to steer as the wheels both want to run straight. There is no mistaking when the locker is engaged.

If you mean unlocked, than I never noticed a difference.