GS977

I bought a brand new zf6 blue tag trans to replace the 90,000 mile one in my 96. it came full of oil from GM. my question is should I run it with the oil that came in it or drain and fill with something better. like amsoil ? here it is.

WVZR-1

I believe if your intention is to run something other than the OE fluid I'd do the change now. I've got a couple ZF's that I've never checked the fluid level in but I assumed they were shipped wet but maybe not full. Yours was full?

I won't start the debate over for lubricants, I've got enough OE for a good while and some to offer with the transmissions when I sell them.

I would run it in gear at idle for an extended period on stands and I don't know that there would be a preferred gear.

rocco16

Is there something wrong with the lube that GM puts in the ZF6??

You should put in something different, like the Castrol fill. It won't do a better job, but it will make you feel better.

mixalive

OMG..
What does GM get for a ZF6 these days?

WVZR-1

My thoughts were that for the price of "knowing" what is going in and knowing also that at some point I will likely need to make a change so it might as well be accomplished "NOW". The factory fill is likely 10+ years old. Does that maybe make sense that you might "just do it"?

dizwiz24

Im using the amsoil stuff and am having great luck.

I did not have any luck with the castrol bmw stuff. It was grinding gears and would not allow full rpm/throttle engagement. The gear shift lever would get jammed and not go into 2nd gear at wot.

I switched to gm syncromesh and all the problems went away

The bmw castrol stuff belongs in bmws, not corvette transmissions. I dont care what zfdoc thinks, it didnt work in my car.

Black89Z51

I wouldn't trust 10 year old fluid. I'm using the Amsoil in my 89. Works fantastic.

GS977

didn't pull the plug on the side to check if it was full but when I removed the plastic cap that goes in the trans where the yoke goes to check the new yoke I just got, the oil in it was pouring out so there's plenty of oil in there. going to drain it and go with amsoil. what is the one I need called? is it synthetic?
If I remember right I paid @ $1500.00 I think for the new trans. it was still in the crate. it's been a few years. just putting it in now.

Black89Z51

http://www.amsoil.com/shop/by-produc...?code=MTFQT-EA

1985 Corvette

WV, do you have the part number for the OE oil? I might check a nearby dealer for some in stock. How many quarts?

1991Z07

actually... Bill is just quoting the MANUFACTURER.

ZF recommends the Castrol, and it works very well. If you were having problems then it isn't the fluid, it's your transmission. Changing the fluid is just putting a band-aid on the problem...it's still there and will only get worse over time.

WVZR-1

1052931 - there are NO replacement part numbers. NONE!

WVZR-1

Yes the Castrol is a "ZF spec'd" product and you certainly can't fault Bill. I've maintained that "frequency" might be much more important than maybe the product except that even some of the synthetic promoters "Royal Purple" comes to mind actual reference their engine oil spec product for OE fluid "interchange". RP - GM 1052931 it's suggested fill is HPS 10W-30.

mixalive

Well.. I totally respect a lot of your opinions on many subjects. But putting the BMW Castrol solved my issue of synchro grinding when hot. And shifts pretty good too. I don't know about WOT shifting. I don't do much of that.

1991Z07

To be fair...the Castrol RS IS an "engine oil"...albeit one with fairly high specs compared to the rest. It exceeds the specifications from ZF for the transmission.

BMW uses it in their "M"-spec engines, which is why you can go up to their parts counter and get it.

bogus

The key is does the oil handle shearing forces... not many oils can. And that is the key difference between engine oil and gear oil.

I have used the OEM, it's fine. I have used the Castrol TWS, and it's ok, too. I am currently using the Amsoil, and find it to be the best. Not by much, but better. It's also easier to get than the BMW fill. Not everyone has a BMW dealer, but there are Amsoil dealers crawling in about every gutter in every town...

WVZR-1

I actually believe the BMW Castrol spec changed a few years ago but it's reported to be the same spec but who actually knows. The RS that used to be available only across the BMW counter is now TWS and I believe much more readily available. Bill says the TWS is a go so that's I guess where everyone gets the reference still. I'd be inclined to use another spec engine oil with no problems. I could never get past the BS discussions the Amsoil "dealers" want to toss around. There's some good guys selling the product but it can certainly be said that they don't "push" the product most "shove" it.

When someone such as RP has a likely quality spec transmission product BUT still recommends another from their line rather than "push/shove" with a comment "it's better" I believe it adds tremendously to their credibility.

Their OE product change is near the end of this PDF.

http://royalpurpleconsumer.com/asset...log_052113.pdf

dizwiz24

I have no idea. It was a terrible choice for my transmission that was instantly solved going to gm syncromesh (btw...the original p/n 5w30 zf oil in my owners manual has long been not available with syncromesh being the replacement).

i have since drained the syncromesh (to go to amsoil) and it was clear. No bronze flecks.

larryinalabama

I had no Idea you could buy a new ZF, I bought a rebuilt for my 90 from rockland gear.

mixalive

Can you post the new GM replacement ZF6 part number?