I know when you come here and read all this stuff it will be confusing. We are all posting our own experiences. But seems like what you're doing has been successful. Just keep you current routine.
My experience was when my diff cover leaked with the RTV sealant, I changed to the gasket and that stopped my leak. My auburn had slippage when I raced at the track with synthetic fluid with the friction modifier added. One way to find out is turn off the traction control and peel some rubber. If you see 2 even black strips your diff is working good.

Leo

 

I do not know about the AUBUM in the 98, I DO know about the AUBUM in the y2k , in reguard to the the syn pkg ,this is only the enguine oil I beleave, But back to the AUBUM
Change @ each 7500 miles

Here's what SLP uses. (Y2K Auburn)
Gear oil = Quaker State SAE 80W-90EP High Performance Non-Synthetic [has a internal additive. Available at WalMart
GM Lubrizol #1052358
2oz - AutoX - More grip = More Noise
4oz - Street - Less grip = Less Noise
DO NOT use a gasket - defeats the properties of the cover
DO NOT use RTV sealant - Additives eat it and the cover will leak.
USE ONLY - SLP Approved Three Bond Silicone Gasket #1216.
Manufactured under license to Suzuki - Part #99104-31160
Available at Suzuki Motorcycle Dealer.
Or Suzuki Car dealer
Part#: 99000-31160 (Suzuki Bond No. 1216

 

I'm not having much luck getting straight answers to these questions:
1) What differential fluid does the optional SLP-installed Auburn Hi-Torque differential require on a 98 SS? Reg or synthetic?
2) Does it require the additive?
3) What should I be using for a gasket?

I keep hearing now from different people that this unit should NOT have synthetic diff fluid. My car came from SLP with the optional "Synthetic Lubes" pkg., so am I correct in assuming that SLP put the synthetic diff fluid into this unit, or was tht just the engine oil?
The car now has about 43,000 miles on it. I changed the orginal diff fluid out at 10,000 miles and installed synthetic 75W90 with the additive and a separate gasket.
I installed 4.10 gears at 22,500 miles and Mobil 1 synthetic diff fluid was used with the additive. The GM tech used a regular gasket. I changed the fluid again at 25,500 miles, again using Mobil 1 synthetic and a gasket.
I use the car on road courses and participate in autoX events fairly frequently (4 or 5 of each per season).
With about 20,000 mi. on this batch of fluid and considering what I do with the car, I figure it's probably time for another diff fluid change before the start of the coming season.
Fortunately, I have not had a single second's worth of trouble or aggravation from this optional, SLP-installed Auburn rear end. It's just that I had never heard conflicting opinions on how this unit needs to be maintained before now.
Do I need to make any changes in my routine?
Thanks in advance.

Best regardSS,

Elie


__________________
TFbM Solo Director http://www.tfbm.org
98 Camaro SS #C079
... a few mods
97 Bonneville SE L67
9" K&N Cone, SLP 3.5" pulley
http://www.geocities.com/sselie

 

what he said above is correct. The QS comes with a bit of additive in it, hence the need for just 1/2 bottle of GM's. I used to put two full bottles at changes in with Torsen/Eaton, but if you do that with Auburn, it will groan.

I used GM fluid at this change, and a 1/2 bottle of additive. I'm using QS and 1/2 bottle next time--got a bit of whine out of it now.