F-Body owner needs fluid advice from the experts...

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Apr 23, 2003
Hey guys, I'm new to this board but old to LS1.com. I'm looking at changing my fluids this spring when I take my car out of storage. It's a 2001 WS6 t/a, 6 speed. LS1.

Oil - Last year I tried mobil 1 5-30, then 10-30, and redline 10-30. I noticed that my motor was the quietest with the mobil 5-30. I don't know why that is, when everyone tells me that it should be quieter from a 10-30. But aren't they the same when hot ? they both have a viscosity or 30 right ? I'm not by any means an oil guru, but this year I was thinking about running 5-30 redline because I know it's a little better than mobil 1, and my motor was it's quietest with 5-30. plus GM recommends 5-30. But I've heard this is only for fuel economy, is this true ??
I changed my oil at 450 miles, then 1500, then 3000, then 4286, which is what my car's at now.
Before I stored my car, I was wondering about the storage of the motor, and what needed to be done to prep it. A tech at the dealership told me to dump in this E.O.S assembly lubricant into the crank case and that would "stick" to the cam and coat the motor during winter to prevent any internal corrosion. Like an idiot I did this and my motor make this horrible ticking noise . So I drained it out, and changed the oil three times after that, driving it about 20 miles in between each change, in the hopes to flush out all that crap. I also added seafoam to the crank case two of the three of those times. That same ticking has always been there but seems to get louder with the increasing thickness of the oil. Worst with that crap in there, little bit with 10-30, and almost quiet w/ 5-30. Anyways, I hope I didn't wreck anything with that crap running in there for about 5 minutes. After that I looked at at the bottle and it said "do not add to engine oil". Also, my car has fresh oil and a new filter, but has been stored for 6 mos. Should I change the oil before I start it due to any moistrue accumulation, or should I change it after all the old gas is burnt out, and the fuel injector cleaner has been burned, because they might contaminate any new oil ??

Rear End - I think I have the torsen diff, and the dealer did a 1500 mile service on it, but I want to change in fresh fluid this year. can I run synthetic fluid ? if so what is the best ? do I need to add that GM friction modifier ? I want to take care or my rear end, but don't want it too slippery so that i'll get one wheel burnouts.

Transmission - That fluid hasn't been changed yet, at 4286 miles. I have a 2001 t-56. What are my options in terms of a really good fluid. I know that GM recommends ATF, but would I be better off with synthetic or conventional ??

Thanks guys in advance.
Some good questions and some I'd like to know as a Z28 ls1 owner! The experts will be here soon with some good info for you and.....
I might be able to throw you some info on a couple of things.

The Torsen LSD is a gear type. There are no cones or clutches to either wear out or "slick-up". You can use pretty much any oil you want. I'm useing Amsoil 75W140 right now. The rear axles are a weak spot on these cars and I'm hopeing the thicker film might help cushion the gears enough to help. It does not require a friction modifier like the Auburn or clutch type LSDs. You can add it if you want. I've heard some say that it helps some with noise. I haven't really had any noise in mine so I don't run any.

There is alot of debate on the T56. My experience has been that it does not like Mobil1 synthetic ATF. I changed from the factory fill to the M1 ATF at around 1K miles. The M1 was a bit notchier than what was in it. A friend {Ford guy} recomended GM Syncromesh. The local dealer tech was totally against it. I called GM Customer Service and asked them. They said it would be OK. I tried it and I like it. I might try Redline next just out of curiosity.
I also found the T56 in my old 98 Formula did not like Mobil 1 ATF either. It caused a cold 1-2 shift grind to show up, and it never went away even when I later switched fluids.
I am running an LS-1 Vette. I have the Amsoil 5W-30 ASL in the engine, the Series 2000 75W-90 in the rear and the Amsoil Dextron in the tranny. I did notice some shifting improvement, but there is still a little "chatter" when shifting at times. (Not sure if this is what others are referring to when they say it's notchy). It feels like the sychros are not matching speeds very well. I would like to try syncrhomesh but there is some concern on the part of the tranny manufacturer with some of the internal parts longevity. I would also like to try Redline MTL, but am nervous about going with something not specified by GM since I'm under warranty. I am also concerned with the potential for a ester based fluid to swell the seals.
I have a 02 Camaro SS LS1

I'm running Schaeffer 10W-30 PAO Blend now in my LS1. It is running fine with no oil consumption. After 1K miles the oil is still green like when it came out of the bottle. I've had no engine noise and no oil consumption since new. I've also used M1 5W-30 and 10W-30 and no oil consumption with them either. I'm now at 5k miles. I'm also reving to 6500 rpms now with my new cam so I figured I might start using a bit of oil but so far it hasn't.

Rear diff I'm using Mobil 1 75W-90 Syn Gear lube. I really like it so far. My rear diff seemed to have a slight whirr sound to it but when I changed to M1 it has not come back.

T-56 I'm using Redline D4 ATF Very noticeable improvement in cold weather shifting and also seems less notchy when very hot outside.

Me = 2002 Camaro, 12000 miles on it.

10W-30 Valvoline Maxlife SL in the engine

Valvoline Durablend ATF in the trans (way easier shifting than factory, but I wan't to run the Mobil ATF in there next, T5s don't mind the Mobil1.)

Valvoline 75W90 Synthetic in the rear w/ Torsen Differential like you.


I plan on going to a XW140 in the rear to allow for better biasing with the OEM Torsen (we shall see), and that means I will likely not be able to run a Mobil product. I might go Schaeffers on this one. However, the valvoline rear end gear oil seems every bit as good as the Mobil (Ive ran both before, no issues with either one). My rear is basically silent for a Camaro
The GM Friction modifier is still recommended by GM for the torsen to reduce a *clicking* noise it can create when turning. I have never experienced this but if you do, you know you need to add it

Your trans is at an oppertune time to change the fluid. I'll bet you'll see all sorts of break-in metal shavings (looks metallic red in the pan) upon draining it. My dad runs Mobil 1 ATF in his vette T56 without one single issue, it seems to shift a lot better than when it had redline in it. Its your call on this one, but most Fbody owners claim they had issues with M1 ATF in the Fbody type double cone synchro tranny (Vette uses a triple cone, I assume it makes a difference when it comes to the oil required...).

There isn't as much information on gear/trans oils as motor oils, but I don't think you could go wrong with Schaeffers, Mobil, or Valvoline.
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