Rear fluid...evaporates?

Topic: Rear fluid...evaporates? (Read 1106 times) previous topic - next topic

Rear fluid...evaporates?

January 09, 2006, 11:07:16 PM

As the topic points out, I'm wondering if the gear oil....well evaporates?

Reason for asking, it turns out looking at my cars records, supplied by original owner, that it has never had rear service. It's had 3 or 4 exhaust replacements, and various other routine things, but no rear end service. Being a trak lock and all, I'd think service is rather important, especially for someone like the original owner of my car. His reason for selling it was just, too old. So I got it for a steal at $200.

So recently it occured to me that my car is making a nice chatter on decel. I haven't bothered taking it apart to look since it is getting replaced in the future, so why bother if the car is parked. It has survived my 4 year rampage of 100 mph highway runs, line lock shows, and powerslides galore. 1 of those years has a stout 5.0 under the hood....same rear.

So why all of a sudden a noise? Loss of fluid? Or just 107,000 miles of same old fluid wear?

Rear fluid...evaporates?

Reply #1 – January 09, 2006, 11:30:19 PM

The rear end is probably the most neglected fluid in a car - I would bet my 300,000 mile Dakota still has the original fluid in its differentials, and I would bet that the majority of cars on this website have their original fluid as well.

That being said, rear end fluid does not evapourate. It stinks, yes, which would indicate that it is giving off vapours, but it doesn't evapourate at any appreciable rate. It does break down, as with any lubricant, but I don't think 107k miles would break it down enough to cause damage (under normal use, of course).

With a chatter on decel I'd look at the pinion bearings (and even the pinion nut - it came loose in an old Toyota truck I had and chattered like hell when i lifted off the gas). I'd also check out the U-joints, which, come to think of it, is the more likely problem.

Rear fluid...evaporates?

Reply #2 – January 09, 2006, 11:59:47 PM

Hmm...never thought of the U-joints...I will be sure to get some new ones before I slap everything together after the engine and 5-speed swap.

Rear fluid...evaporates?

Reply #3 – January 12, 2006, 03:08:18 AM

I would change the fluid. just for peice of mind. then inspect the inside of the differintail for wear.