Yeah. i have had my car for 2 years and never even added to the diff. how often should i take off the plate and put new stuff in. also will i need a new gasket, and what kind of sealant. thanks
Rick

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Rick
90 Camaro RS 305 TBI
400 small block, Hooker 1 3/4 LTs, Random Tech Cat, Hooker aero chamber cat back on the way!!
TH700-R4 with Trans-Go shift kit (corvette servo here...but not installed yet)
MacEwen Motorsports White Gauge Overlays
14" K&N X-Stream Open Element
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window
http://www.geocities.com/esvalenz

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

"Just because I've done it, doesn't mean I knew what I was doing!" - Me

 

Unless you drive like a jackass or you have a leak or something (or get water in the gear oil), change it about every 20-30K miles and it will be around for a long time. You'll need a couple quarts of Mobil 1 75W-90 synthetic diff fluid and some limited slip additive (GM) if your car is so equipped. Grab a fel-pro gasket at autozone or napa or wherever you want to, and you may want to run a light bead of Permatex to make sure it doesn't leak (just remember the better you seal it up the more time you'll spend with a scraper the next time you do it). Hope this helps.

 

I think 7500 miles is the recommended interval...I just did this and unless you're really careful plan to smell like rotten hard boiled eggs for awhile!

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Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: GMPP 8MM wires, Accel cap&rotor, AC Plugs
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, flow tech headers on the way,
engine swap and 4th gen seats in the works...

 

BB,

GM service intervals say 7,500 miles for severe duty or trailering, never for "normal" conditions. Since most drivers DON'T operate their vehicles in a manner that would qualify for their definition of "normal", changing is a good idea. If you load it heavily and frequently (burnouts, lots of racing and hard accelleration) you should change the oil, and add the limited-slip additive if you have anything but an open differential. Even the ZT axles are supposed to get the additive, according to GM (check the archives for that thread - I learned something that day, too).

Since I fall somewhere between "severe" and "normal", I change mine evert 15,000 miles or so. It can be a little messy, but a large diameter drain pan works well to contain the mess. If you have a Saginaw (now known as American Axle) 10-bolt differential, be very careful about what gasket you use. Since the late 1980s, the stock GM gasket doesn't have the necessary oil holes to feed the outer wheel/axle bearings, whereas the FelPro replacements have the slots/holes.

Inspect the differential cover. You will notice an indentations on each side in line with the axle tubes. These indentations are to allow the flow of oil through two holes in the differential case. The oil flows out the axle tubes to lubricate the axles and the outer bearings. These holes actually have two purposes, one is to be used by a case spreader to reinforce the case during factory assembly (pressing in the axle tubes). The other important function of the holes is to allow some additional lubricant to feed the outer axle bearings, especially under severe service. In order to allow oil to pass through these holes, the differential cover gasket should have two corresponding holes. GM says it isn't necessary, but why not have the extra lube available?

Instead of the GM gasket, use the Fel-Pro RDS 55028-1 gasket.



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Later,
Vader
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"I know how to solve your problem, but I can't tell
you since you might use the information illegally..."
Adobe Acrobat Reader 4.0

[This message has been edited by Vader (edited February 08, 2001).]

 

thanks V,
sheeet. i already did it though, i got the one it specified at the part store (rds 55072) it lined up right...but like the gm it doesnt have the holes. i did wonder...when i took off the old gasket...why it covered em. oh well....next time. thanks anyways. all went well...

 

can you still get gaskets for 9 bolts??

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1987 Formula 350, headman hedders, Accel supercoil, cap, rotor.
MAF screens removed. 160 degree stat and manual fan switch.

Best ET: 14.745@91.317mph-Stock
Best ET: 14.418@95.51 mph-Modded
Ridiculed Founder of the Traction Impaired Crew

 

I just used that blue permatex stuff w no gasket and it hasn't leaked yet. Easier to remove when it comes time to change the fluid every 10miles.

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89 GTA G92
305 TPI
WC 5spd w/3.45 rear
Accel Cap & 8mm Taylor's
Crane Ignition
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch
Hypertech Thermomaster Chip
Steel Rad
Cat back 3" Exhaust
HiGh FlOw Dynomax Cat

 

Ditto, I just used permatex.

 

Wow, Vader, thanks! I've always used FelPro #RDS-55072, and it looks like the stock gasket. I'll have to hunt down that other one next year. (I change the rear diff fluid when I do my yearly tuneup.) Altho I guess I could modify #55072 with a punch, eh?


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