silverbandit

when I was getting the oil changed today I noticed when the car was on the lift there was some fluid on the rearend/transmission how do I check the level and what kind of fluid do I use and how do I find out where the leak is

81c3

The leak is probably the shaft seals. its pretty common on these cars. Get the car level on the lift or jack stands. Pull out the fill plug. If oil comes out, its full. If its just a hair below the threaded fill plug hole, its also fine.

happiedazs

Get under the car and clean up all the oil with a rag and laquer thinner so you can see where the leak is coming from in the future.
Then take the car for a 1/2 hour highway trip to get the differential oil warmed up. Then get under the car and open the fill plug -- see if any diff oil spills out. If not, put your finger in the hole to see if the oil is a little below the hole --- if it is, you are OK on the oil. Sometimes the Diff is a little over-filled and when the oil in the rear gets hot it expands and can push oil out of the overflow on top of the diff. If you're really down on the oil level, then one of the seals (usually the left one --- divers side) needs to be replaced. As someone said before, differential leaks are unfortunately common on C5 vets and replacing the seals is not cheap. Hopefully, it's just an over-full issue. Good luck

jlaw1313@comcast.net

After inspection, you may want to consider a differential breather vent mod. Worked for me. Search corvettebob1 or ZeeOSix on the forum they both were very helpful.

http://forums.corvetteforum.com/c5-t...d-removal.html

$$$frumnuttin'

I wouldn't assume the fill plug is obvious....a pic would help him see what it looks like and where it is...

Abnmarine

This will help.

http://www.toquez06.com/diff.html

happiedazs

I get a leak in my rear from time to time. It only seems to happen when I take longer trips in the summer when I do a highway road trip of say two hours and I am mostly driving at a constant speed of around
60MPH - 80MPH. I think the small amount of oil ends up coming out of a vent on the top of my differential. My trans oil is not overfilled so for some reason I think all the sloshing around of the oil in the diff pushes some oil out of the top --- don't know why this should be, but that is where my occfasional leak seems to come from. Maybe I should try a different trans oil that won't expand or foam up so much. Perhaps you have the same issue (minor).

Bill Curlee

The rear-end takes 75/90 weight lube and the lube MUST contain a limited slip clutch modifier OR you have to purchase it and add the required amount. Otherwise, you will damage your limited slip clutches.

The MN6 and MN12 Manual trans takes ATF fluid. Depending on the year, you have to use standard ATF for the early C5s. The later C5s can switch to synthetic ATF.

All manual transmission C5s can use AMSOIL Torque drive and that is a outstanding upgrade from the standard OEM ATF fill

If you have an A4 automatic,, the procedure for checking the ATF level is quite complicated. DO NOT do it without having the exact service manual procedure in front of you!! It takes the standard ATF fluid.

Bill

C66 Racing

As mentioned above, left axle seal on the diff is most common leak point. I've gotten to just changing mine once a year at the start of every season - the actual seal is only about $30 or so and it just takes me about a hour to pop the upright off its ball joint, pull out the axle to get to the seal, replace the seal and put it back together.

Diff takes ~ 1.7 qts of synthetic 75w90. Manual tranny takes about 3.5 qts of Dexron III ATF. Auto tranny takes about 5 qts for a drain and fill, ~11 qts total fill which you really can't do - also of Dexron III ATF. Note GM stopped licensing Dexron III several years ago though many aftermarket companies still make fluid to this spec. GM says Dexron VI is backwards compatible for autos, but they have new part number 88861800 for the manual ATF spec.

Also as mentioned above, checking fluid in diff/manual tranny is done by opening the fill plug and seeing if fluid level is near the plug - might have to stick your pinky in the fill hole to check to see if level is just below the hole. The diff fill plug is the hex bolt on the back face of diff, slightly on passenger side and just over half way to top. Tranny fill plug is drivers side about halfway forward and halfway up (may have temp sensor plugged into the fill hole).

I personally use these at the track in my 02 Z06:
AMSOIL Torque-Drive Synthetic Transmission Fluid (Product Code ATD1G)
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT)

Bill Curlee

EXCELLENT INFO!!

Merry Christmas!!


Bill

silverbandit

thank you everyone for your info and MERRY CHRISTMAS

All_Motor_C5LS6

Excellent Info