Dino or Synthetic in Differentials

Status
Not open for further replies.
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne
 
Originally Posted By: wtd
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne


Just wondering, did you ever change the fluid again from the time it was new to the 75K mark?
 
Originally Posted By: Hootbro
Originally Posted By: wtd
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne
A GM problem.

Just wondering, did you ever change the fluid again from the time it was new to the 75K mark?
 
Originally Posted By: kschachn
Originally Posted By: Sunnyinhollister
On the Jeep boards it is taken as gospel that synthetic gear lube has LESS thermal conductance than mineral oil and the gears run hotter. Currie will actually void your warranty if you run a synthetic gear oil. Apparently there was a rash of failures and synthetic was blamed.


Stuff is always blamed for things when in reality there is no demonstrated correlation. And, a lot of things are "taken as gospel" when there is no supporting evidence either.


Very common.
 
Originally Posted By: wtd
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne


What fluid did you replace the M1 fluid with?
 
Chevy specs synthetics for our truck based Tahoe, but they are quite specific about using their special lube.
 
Originally Posted By: wtd
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne


Might not be fair to blame the lube.
We had a Jeep Grand Cherokee that had 3 differentials in it within 40,000 miles before we dumped it; just a plain old bad design. They (differentials) kept working the bearings and developed very loud whines. Our Last Chrysler product.

Our Tahoe has a mild whine and has the original lube. Maybe it's just a symptom of the beast.
 
Last edited:
I agree that synthetics are prime for use up here. Its why I use them. Cant argue with cold flow properties. As well certain manufacturers will extend warranty with synthetics. Must be onto something.....
 
Originally Posted By: Beem
Originally Posted By: wtd
I no longer use synthetic diff fluid in my 98 chevy Z71 truck. It may be a coincidence but when the truck was fairly new, I changed both diffs over to Mobil 1 diff fluid. At around 55,000 miles, I began to notice some rear end whine. I finally had it looked at at about 75,000 miles when the noise was getting pretty loud.

Shop tore it down and the pinion and carrier bearings were shot. This was on a truck that hardly ever pulled or hauled anything. I had it fixed and now at 130,000 miles, everything is still quiet.

Wayne


Might not be fair to blame the lube.

I agree. Bearings fail for many reasons... e.g., debris denting, inclusion spalling, improper preload, etc. It's not fair to blame the fluid without reading the failure pattern on the bearing.
 
Status
Not open for further replies.
Back
Top