ZF 6 speed oil change

[a65l]

As part of the process of making anew car mine, I like to change lubricants. I had a real suprise when draining the old oil, it was absolutely turqouise in color and smelled like gear oil. Came out thin though, it was a little warm but it ran more like engine oil than gear
lube. I've really never seen anything like it... any ideas?

 

[Hib Halverson]

That's Red Line Light Shockproof gear lube. As far as protection and lubrication during severe duty such as road racing or very aggressive street driving, it's perhaps the best lube for a ZF S6-40.

I use it in my ZF along with most of my other manual transmissions.

 

[a65l]

And it's cheaper than the GM oil......

 

[evl_twn]

Did you swap out the backup light switch while you had it up in the air?

 

[a65l]

Heh. Considering I forgot to bring the fluid to do the clutch, and didn't get a fuel filter, I would think the answer is obvious. Plus, the backup light switch is a discontinued part number according to Chevy. Haven't checked the aftermarket but I'm sure I can find one.

 

[93Rubie]

I would get the Redline Lightweight Shock Proof again and put it back in. Hib recommend it to me, and I am happy with it so far. Plus, the added protection for the gearbox is almost priceless. ZF cost some $$$ to rebuild. A little prevention is worth a lot of cure. I used Redline gear oil in my diff. as well.

Summit Racing has Redline Products. FYI, the GM Syncromesh Fluid is not what came in your ZF originally and is NOT anywhere as good as the Redline Product.

 

[a65l]

I saw a blurb in a post about running an anti foaming agent with the Red Line shockproof. Any ideas there?

 

[Hib Halverson]

I saw a blurb in a post about running an anti foaming agent with the Red Line shockproof. Any ideas there?

No "anti-foaming agent"--or any other additive for that matter--is necessary when using Red Line Light Shockproof Gear Lubricant.

 

[2VettesMike]

As part of the process of making anew car mine, I like to change lubricants. I had a real suprise when draining the old oil, it was absolutely turqouise in color and smelled like gear oil. Came out thin though, it was a little warm but it ran more like engine oil than gear
lube. I've really never seen anything like it... any ideas?


View attachment 3250

Don't panic. The GM Synchromesh gear lubricant (basically engine oil with an additive) is the factory lube and works just fine, 170K and still clicking off great shifts.

Good luck,

Mike

 

[Hib Halverson]

Don't panic. The GM Synchromesh gear lubricant (basically engine oil with an additive) is the factor lube and works just fine, 170K and still clicking off great shifts.

Good luck,

Mike

What GM sells now as "Synchromesh" gear lubricant, or whatever they call it, is not the "factory lube". The factory lube was a Havoline 5W30 engine oil which GM and ZF agree upon and that GM purchased from Texaco.

Problem is, Texaco stopped making that blend of engine oil several years ago. What "GM Customer Care and Aftersales" (used to be "GM Service Part Operations"--SPO--and before that "GM Parts Division") sells now is not the same. It is not known (but I think unlikely) that, almost a decade after the last ZF S6-40s were used in production, that GM went to the trouble and spent the money to have a lubricant supplier certify a new product, so GM probably picked a GL4 lube it was already selling and now markets that as the "factory" lubricant...and puts an obscene price on it.

That said, it is true that this "factory" lube meets minimum requirements (specifics unknown) for use in the S6-40. Some also like a Castrol 20W60 engine oil, which is, also, said to be approved by ZF for use in the S6-40, but others say it needs to be changed too often.

The best lubricants to use are either Red Line MTL (which is what the transmissions were raced on back in the late 80s and early-90s) or, even better, Red Line Light Shockproof.

I've used Light Shockproof for over a decade in two different ZFs with excellent results. Several years ago, I took one of them to Bill Boudreau (the "ZFDoc") for teardown and inspection. He was surprised, considering the miles on that trans and how it was used, that wear on some parts was no more than what you'd see just past break-in. He didn't like the pastel blue color, however, and calls it "Martian Blood".