VRSCDX

Hey y'all!! Just got my first Corvette!!! A 1996 LT4 with the ZF 6 speed!!! I am sure this question has been asked and answered 1000 times in the forum, but, where are the ZF fill and drain plugs located??? Also what lubricant is recommended??? Dont have a manual for it yet but want to change the trans and differential(?) fluid!! Thanks in advance for helping me learn about my dream car!!!!

VetteMed

Drain plug for the ZF is on the bottom of the trans,

Fill plug about halfway up on the RH side of the trans.

Most popular fluid is Castrol TWS 10W-60 available from BMW dealers. You'll need to buy 3 Liters.

Kubs

Welcome to the Forum!

The drain plug is in the middle of the transmission on the bottom, and the fill plug is on the passenger side about half way up. Be sure to loosen the fill plug before trying the drain plug. Sometimes they tend to be stuck and it would be bad if you drain the fluid only to find out you cannot get the fill plug out.

For fluid I highly recommend the AMSOIL Synchromesh Fluid:

AMSOIL Synthetic Synchromesh Transmission Fluid (MTF)

http://kahunamotorsports.com/mtf-product-page.html



For the differential I recommend the AMSOIL Severe Gear 75W-90 oil. It does not need any additional limited slip additive.

Severe Gear 75W-90 (SVG)

http://kahunamotorsports.com/svg-product-page.html





I use both those products in my C4 race car and I am very pleased. Let me know if you have any questions on either product.

PLRX

How did you find this forum?

VRSCDX

I have been a member of the forum for over a year!! Joined when I was trying to buy my deceased brothers 1995 Corvette!! That fell thru and just bought my 96 LT4 last weekend!! And thank you so much to all who replied with pertinent info!! It is much appreciated!!!

93Rubie

The Amsoil seems to be good, a lot of guys run that.

I run Redline Shockproof Lightweight gear oil in my ZF, good ol' smurf blue.

Running Redline 75-90 Synthetic gear lube for the diff. No complaints.
Get a siphon gun for the rear end lube.

LT4 F45

How many quart are needed to fill the diff?
I know that the ZF is 2.1

Kubs

Total fill is 1.8 qt but unless you get every drop of the old out it will probably be around 1.5 qt. If you jack the car so it is level just fill until the fluid drips out the fill hole.

LT4 F45

Thanks for the quick reply,
was just to make sure to buy the right amount...

techvette

Go with the German Castrol from a BMW dealer for the ZF - do a search for the part number. The gear oil for the diff is available from GM (again, search for the part number) and add TWO bottles of limited slip additive to it (also available from GM) as recommended by Gordon Killebrew.

WVZR-1

Why on earth would you want to "double up" on the additive?

Purple92

I use Redline MTL in the ZF gearbox and Redline 75W-90 in the diff.

You will need a 17mm allen "key" to remove the ZF fill and drain plugs - they can be fairly tight - especially when they've been in for a while.

Have Fun with the car - the LT4 is a Very nice motor.

96 lt-4

That is what I ran in mine when I swapped gears and serviced the trans.

GREGGPENN

I've tried GM (before it was discontinued, Castrol 10w-60 (as suggested here), and AMSOIL (as suggested above).

AMSOIL was/is the best. Castrol was too thick in mine. IMO, it's better suited for climates where temps stay in the 70-110 deg range. AMSOIL is a better all-round fluid -- and it shifts best with AMSOIL.

LT4 F45

Done the ZF change with Amsoil and it is smooth as never
But did the rear end at the same time with Amsoil too and now i have a strange sound when turning a corner...
Did not add any additive since you guys have said that it was not needed with Amsoil Severe Gear 75W90...
I fill it till oil drop by itself by the fill hole and put back the plug when fluid was still dropping, Did i put too much oil? Or i will have to drop some and add a anti-slip additive?
Any advise will be gladly welcome!

gears

I just did my oil and tranny last weekend with amsoil in both

Kubs

What kind of noise are you hearing? Is it the tire scrubbing/chirping on the ground or is it a whining type noise? Try doing some figure 8s in an open parking lot to work the new fluid into the clutch packs and see if the noise goes away.

corvetero

Well, everyone says is not mandatory to add anti-slip additive, but I guess in case you add that one would be even better.

BTW, maybe your diff. wasn't in a good shape before the change of fluids, who knows?

LT4 F45

it is a whining type noise
I will try the 8 figure but i never ad this sound before and my vette and Dana 44 are at 42K miles...

96GS#007

Anti-slip additive does not address whining. The additive is to prevent clutch pack chatter which you will hear/feel as popping as the clutch packs stick together and then break free. Whining is bearing or gear related. Are you sure it's the differential making the noise and not a rear hub? FWIW, severely worn rear brake pads will also result in a whine coming from the rear of the car.