I just changed the rear diff at 17500. Besides being scared cause I used 75-140 AMSOIL 2000 series and it looks like maybe I should have used 70-90 I have come across some very interesting wear patterns. Please let me know if anyone else thinks this looks a little weird. I am getting ready to haul the old TT up some major grades and feel a little concern....

What do you all think!

Tom

 

That is intresting. You should be fine though. I wouldn't worry to much.

 

Did you find out what it is? How long did you run the 75-140 for?

 

I took the pics into my local five star and they said, "Oh, there fine." I asked if they would sign a piece of paper stating that and boy they ran like their house was on fire. There's no mating marks on the ring so we'll see what happens.

I still have the 75-140 in the diff. As hot as it gets here and with a big tow in her near future, she'll be fine! I must have seen something about this weight oil or I wouldn't have put it in. I'll be through 15K more miles in no time, we'll revisit lube weight at that time.

 

If those lines I see in the picture is what your talking about next time I open it up I would check the back lash and do a lift check on the pinion just to be sure the bearings are OK. I haven't took a lot of differantials apart but your right it don't look too good!

 

Why did you have to change the rear diff at 17500? Or was that diff lube at 17500? What was scary about Amsoil 75-140? The Dana's called for this weight of lube; the AAM's call for the lighter stuff.

If the diff isn't making any noise, I wouldn't worry about it. That Amsoil won't hurt it either.

 

BTW, did you happen to take the time and look at each tooth on the ring and pinion gears?

 

The reason I worried was my 03 service manual calls for the lighter weight oil. I looked at every tooth I could see without jacking up the rearend so I could spin the gears. No noise from the gear-end before or after lube change, so I aint worring about it...

Sorry 'bout the syntax, the diff lube was 17500 miles old. The gears are now 18000 miles old (They stayed) My typing always makes sense to me no matter how many times I proof read it, it takes someone pointing out my mistake to realize it....

 

Tfeore,

How deep are those marks? Can you catch a fingernail on them, or are they smooth?

The way those lines are so uniform, it almost looks like they could have been applied deliberately, but I didn't notice anything like that when I did mine at about 13,000 miles.

Also, my dealer recommended Redline 75-140, and said they now suggest the heavier weight for folks who tow, and it would not void warranty.

 

I touched the marks with a scribe and couldn't really feel anything. I may over pay the dealer to do the next change so they can check B.L. and rotate through the gears...make sure it's all good.

As far as I can tell, if the dealership I go to even finds something shy of OEM spec's they just change it out. Must like DC money...