Baystate Jeepers

Changed my front diff lube and had flakes in front diff lube, jeep has 120k miles and I have no clue when the fluid was changed. Is this a bad sign? Going to go a couple weeks and recheck to inspect.

Did you pull the cover when you changed fluid? Lots of flakes or just a few flecks?

Yes , pulled the cover. Well what would be a lot of flakes? When I wiped the inside down with a blue towel, you could see the flakes.

I also mention this because Chris at Lou's could not get the preload to 30in lbs, which could be a bad sign, I was told.

That would be in the lot of flakes category.

Sounds like best case, you have worn out bearings somewhere in there. Worst case the bearing caps have spun out and chewed the housing. With a worn ring/pinion or carrier being the middle case.

johnsxj wrote: Sounds like best case, you have worn out bearings somewhere in there. Worst case the bearing caps have spun out and chewed the housing. With a worn ring/pinion or carrier being the middle case.

ouch.......

Chris wrote: I also mention this because Chris at Lou's could not get the preload to 30in lbs, which could be a bad sign, I was told.

why were they setting the preload? What other work were you having done?

Most pinion preload is around 20 " pounds. John was on the right trac, You should pull the bearing caps to see if the bearings have spun in the caps. Mark the caps , Rt. top , Lft top , so they go back in the same direction and same side. There are factory punch marks on each bearing cap but if you arent familiar with them you might as well mark them so you will be certain. Is there a bazillion miles on this diff ? Any noises,whirring,grinding . GITERDONE !FjR68

Ok so the reason why Lou was setting the preload is because the shop that did my pinion seal f'ed up big time, according to Lou. The shop did not use a new pinion nut, no red loctight and used an impact wrench to set the nut. So Chris showed me the play in the pinion (up/down motion) which according to chris, preload was not established. Well at the same time chris checked the diff fluid and the fluid contained flakes. Since then I changed the fluid and put ~300 miles on the jeep. I will pull the cover again tomorrow to inspect the damage, if any.

Frank - this is the original D30 and has only been off road since I bought the jeep last year.

How common is it for the bearing caps to wear? How much is it to replace bearings?

Chris wrote:The shop did not use a new pinion nut, no red loctight and used an impact wrench to set the nut.

what a-holes. Service manual (yeah, I read tech manuals. But that doesn't mean I'm turning in my man card!) calls for a new pinion nut and goes over the torque specs. And in bold letters says Do not over-tighten If a dweeb like me understands that, why can't a mechanic? Just takes a few more minutes to do it right instead of half-azzed

The shop was Keene Drivelines, just wish I had some sort of recourse. They also marked the nut/shaft using a cut off wheel, so he knew how tight the nut should be when re-assembled. The problem with that theory, he installed a completely new shaft.

Chris wrote:The shop was Keene Drivelines, just wish I had some sort of recourse. They also marked the nut/shaft using a cut off wheel, so he knew how tight the nut should be when re-assembled. The problem with that theory, he installed a completely new shaft.

There should be some recourse, though you may not get much... First, contact the shop which did the work and explain the issue (if you haven't already). If they don't offer to make it right then, if you paid w/ a credit card call the card company up and talk to them about it and say that you want to dispute the payment. You may need to get another shop (e.g. Lou) to writeup something, but I bet you can get something.

I was able to do this with a wrecking yard that gave me a junk part and get my $ back even though they said "no refunds" once I got the credit card company involved.

JW

Last Friday I removed the diff cover and changed the fluid. This weekend I put ~300 miles on the jeep and today I drained the new fluid. I did see the metallic looking flakes (very very small flakes), but not as many. Perhaps the fluid was never changed prior to me owning the jeep, however I would think the flakes would of been much smaller (powder like).

This time I snapped a couple photos.











All 24 photos can be seen here...
http://s31.photobucket.com/albums/c388/ ... kesindiff/

This is your D30 up front and you weren't in 4wd for all that mileage you put on, right? I think the D30 uses crush collar to set the pre-load. Is that why Lou wants to set it to 30 in-lb (assume pre-load was at 20 + 5 for re-crushing + 5 for new seal) Hard to tell what the pre-load was since the guy never measured it.

norstar wrote:This is your D30 up front and you weren't in 4wd for all that mileage you put on, right?

Yes, Lou stated that it did not matter if I was in 4wd, just needed to change the fluid and re-check.

norstar wrote:I think the D30 uses crush collar to set the pre-load. Is that why Lou wants to set it to 30 in-lb (assume pre-load was at 20 + 5 for re-crushing + 5 for new seal) Hard to tell what the pre-load was since the guy never measured it.

The person that changed the seal, marked the nut and shaft and re-tighten to that mark. However they installed a new yoke, which I believe throws off their measurement.

I have read several threads now where some folks just mark the pinion shaft & nut, some that measure the preload with tires /breaks removed and some that re torque to 165ft lbs. All 3 appear to have a good success rate.

FWIW - I prefer, if posible to work on my own jeep only b/c I know what exactly has been done. Right now I don't know if I am just being paranoid.

Chris wrote: ...installed a new yoke, which I believe throws off their measurement.

Wouldn't be such a pita if he measured the pre-load...
So are you going to take everything ( i mean axle, carrier and pinion) out and get a new crush collar to reset everything back to spec?

norstar wrote:Wouldn't be such a pita if he measured the pre-load...
So are you going to take everything ( i mean axle, carrier and pinion) out and get a new crush collar to reset everything back to spec?

If I was just installing a new crush collar, do I have to completely re-shim? I am thinking it might be a good idea to check the pattern while the cover is off.