Diff fluid question..

[Phat3800]

How often should rear diff fluid be changed?? My car has just under 37 grand on the clock, so I'm wondering if I should get that done..

[Morgan]

If the vehicle sees a fair amount of track time or is driven hard I like a 7500 mile interval. All I've done to the rear end of the black car is change the fluid & posi additive every 7500, and it has lived almost 160,000 miles yet still puts up with 60-foot times in the high 1.40s at the track.

Hope this helps,
Morgan

[ March 14, 2003: Message edited by: Morgan ]</p>

[nikon]

GM recommends you to it, or get it done after 24,000 It had totally slipped my mind, I do it every 10000, my car doesnt use the posi "much" anymore...the harder you use that diff the morefrequently you should change it ;)

[MustangEater8251]

yep change it...

I plan on doing mine soon.

[Bliggida]

Not to be rude, but I see this all the time, and when I do it amazes me.

People will buy a hair-dryer for $19.95 and refuse to turn it on until reading the manual for it, throughly and completely...when you figure out which side is the english version.

But that same person will purchase a $20,000.00 vehicle, take it off the lot and drive it for years without ever reading the owners manual. I don't understand that???

There is a lot of helpful info that GM took a long time to gather and print for you to help you maintain your GM car and make it perform its very best.
It even tells you how to put your seatbelt on correctly. If I remember correctly that took up 5 pages. But hey - theres a lot of detail that goes into "ZZZZZ-KA-Click!" :rolleyes:

Anyway, check your service manual, it has a comprehensive maintainence guide, and it even provides you with a 'notes' page(s) to mark down where, when, what, and who maintained your vehicle.

[chas]

its hazy, but i believe the suggested service interval is 30,000 miles (about every 2 years, at 15,000 a year). same the as the transmission fluid if i remember right.

[strobhen]

Bliggida...

Makes me think you have not read YOUR manual.

I have a 2001 firebird and NOWHERE in the manual does it say anything about the differential fluid change intervals.

It refers you to the scheduled maintenance section in the back which makes no mention of it in over 150k miles of scheduled maintenance.

So get off it and lose the attitude.

[sped214]

I don't want to sound stupid, but here goes. How do I change the diff fluid? Is there a drain/fill plug, or do I need to remove the cover. If so, how do I fill it? Any help would be appreciated. Thanks. (Mine's never been changed since I bought the car, and I've had it for about 60k miles.)

[RamAir95TA]

<blockquote>quote:</font><hr>Originally posted by sped214:
I don't want to sound stupid, but here goes. How do I change the diff fluid? Is there a drain/fill plug, or do I need to remove the cover. If so, how do I fill it? Any help would be appreciated. Thanks. (Mine's never been changed since I bought the car, and I've had it for about 60k miles.)<hr></blockquote>

You'll need to remove the cover. There's no drain plug.

Remove the cover and drain the fluid. Clean out the excess fluid with a clean rag. Use a new gasket (or RTV) and reinstall the cover. There's a plug on the passenger side top of the differential housing that's designated the fill plug. Fill it up with 75w90 Mobil 1 synthetic gear oil and one bottle of GM limited slip additive.

Pretty simple process actually. [img]tongue.gif[/img]

[sped214]

Cool. Thanks. I'm assuming I can get to the fill hole without having to drop the rear end?

[RamAir95TA]

That's correct. It's on the passenger side just above the axle tube.

[Dominic]

I change mine initially at 10K, then at 30K, and then every 30K from then on. I do the major tuneups at 30K, its a good interval for my driving style.

On a truck that tows, 15,000 is best. The rear gear oil holds up well, you are really pouring good fluid down the drain if you do it sooner than 30K if you run a good synthetic.