i just bought my first corvette after years of wanting one its a 92 lt1 6 speed coupe and i'm so excited.
the previous owner has never changed the tranmission fluid, i thought while i have the car on a friiends hoist and im changing the oil and filter i would change the transmission and rear end fluid as well with a good synthetic, the car has 85,000 miles on it. i e-mailed mobil and asked where i could buy synthetic fluid for the transmission their response was--- mobil does not have a fluid that meets the gl-3 spec for the corvette 6 speed transmission, their understanding is the tranmission uses dextron III and in that case i can use mobil 1 synthetic automatic transmission fluid.
does anyone know if thats the case and if not who else has the synthetic fluid i need.
this is my first post i hope it works ok.
who in the wide world of sports told you it used ATF? the zf uses motor oil, GM sells oil specially made for the zf and so does the BMW dealer. redline also has an oil a lot of people swear by even though i can't rememeber which one they use.
The three lubricants I've heard the ZR-1 guys using in there ZF 6 speeds is GM's recomended lube from the dealer, Castrol 5w 60w synthetic from BMW dealers, and Redline MTL synthetic. I know the manual says the factory fill never needs to be changed but I change mine once a year with Redline. They hold 2.5 quarts. Tip: 17mm hex head, remove the fill plug first sometimes there a PITA, that way you won't be stuck with a drained tranny incase you have trouble removing the fill plug. I have never heard of anybody using ATF in the ZF but who knows. 84 CF 91 ZR-1
Go for it i guess... Just never heard nyone doing that. I dont know. I guess I just like to play it safe and go with something I know works. not worth it to me to find out someone didnt know what they were talking about at the expensive of my tranny.... Im not saying hes wrong... Im just saying...
Yes, Dexron II or III is recommended by ZF. I emailed their lubricant specialist about a year ago. http://forums.corvetteforum.com/zerothread?id=279587 A couple of days ago I installed the mobil 1 synthetic ATF. No complaints, it shifts like with the GM fluid.
I bought a 94 six speed about three months ago and put synthetic 5W-30 in the ZF 6 speed and was not happy at all with it! Don't make that mistake! After reading some threads on this forum, I followed their advice and went to the BMW dealer and bought the Castrol Synthetic 10-60. It made a huge difference and I am very happy with it.
I ahppened to stop by the dealer today and asked them for the part # - in my case, I changed the fluid when I did the clutch last year, and I wasn't 100% sure that they gave my wife the right stuff when she went on a parts run.
Anyway - the dealer today said that p/n 1052931 is the correct part. Showed me a tech bulletin as well that listed this for the ZF6 equipped c4's.
Thinking back - the stuff I put in last time was in a clear small bottle. Not the white guart-size they gave the wife last time :mad Guess I have something to add to the to-do list when it's not too cold to lay on the concrete. Curse you single-car garage! :boxing
I recommend the Castrol/BMW stuff. Do a search on the forum and you should be able to find the BMW part number.
Also, buy yourself a fluid pump to refill the tranny as the fill plug is on the side. I got a pump action one for like $3 at pep boys.
EDIT: zfdoc recommends only the GM or BMW part numbers, I have heard many times before that these are the only acceptable fluids. If you really have an inkling to use ATF I would call ZF directly and ask them.
Here is a response I received from ZF Industries when I enquired about frequency of transmission oil change.
Thank you for your interest in ZF Industries, Inc., especially in the spare
parts program for all 89 - 96 Corvette 6-speed manual transmissions.
The recommendation from ZF Industries, Inc. for servicing your transmission
is to change the oil every 30,000 miles.
In regards to the recommended oil, ZF Industries, Inc. approved only two
kind of transmission fluid for the S6-40 6-speed manual transmissions.
Either the GM Oil with GM part # 1052931 or the Castrol Formula RS 10W60.
Please contact our distributor (information below) about price and