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I plan on changing the rear diff fluid and knowing the local dealer doesn't see many Corvettes, I plan on doing it myself.
I do most of the work on my cars, but never changed rear diff fluid before.
Can anyone share some tips on the process?
Things like:
Recommended rear diff fluid
Recommended place to buy fluid from
The car will be on 10" wheel ramps... will that give enough clearance for comfortable fluid change?
Are there plug seals that need replacement?
Any need for bleeding any air after refill?
Any recommended tools to help with refill (pump?)?
Any other tips for making the job easier are more than appreciated!
Doesn't really apply in the OP's situation since the car is so new, but, I always remove the fill plug before the drain plug. Wouldn't want to drain the gear oil- or trans fluid- and not be able to refill it if the fill plug strips or is seized.
Recommended rear diff fluid
I used the recommended GM fluid.
Recommended place to buy fluid from
I bought it and a small hand pump from Amazon. Best price I could find.
The car will be on 10" wheel ramps... will that give enough clearance for comfortable fluid change?
Not sure on that one. I used a lift.
Are there plug seals that need replacement?
No.
Any need for bleeding any air after refill?
There is a need to run the car in gear with the rear wheels off the ground to purge air from the control pump. It's covered in the procedure that I believe is listed in the C7 sticky procedures. If it's not there, I'm sure someone else will chime in.
Any recommended tools to help with refill (pump?)?
Yes, a hand pump is almost mandatory. The fill plug is NOT easy to get to but it can be done.
GREAT suggestion to remove (loosen) the fill plug first!!!
Recommended rear diff fluid
I used the recommended GM fluid. That would be DEXRON LS.
Recommended place to buy fluid from
I bought it and a small hand pump from Amazon. Best price I could find. Me too.
The car will be on 10" wheel ramps... will that give enough clearance for comfortable fluid change?
Not sure on that one. I used a lift. Should be high enough. It was for the C6 and C6 Z06.
Are there plug seals that need replacement?
No.
Any need for bleeding any air after refill?
There is a need to run the car in gear with the rear wheels off the ground to purge air from the control pump. It's covered in the procedure that I believe is listed in the C7 sticky procedures. If it's not there, I'm sure someone else will chime in. If you are not comfortable with the shop procedure, you could just put the car back on the ground and drive it around the block to purge the air from the circ system. Lift the car and recheck the fill level afterwards and you will likely find that it will take a few more ozs of fluid to reach the full level.
Any recommended tools to help with refill (pump?)?
Yes, a hand pump is almost mandatory. The fill plug is NOT easy to get to but it can be done. A short piece of 3/4" steel pipe as a cheater bar over the socket wrench will help you better wrench the fill plug loose. It isn't an easy reach upward on the C6 and likely the same on the C7. If like the C6, the Fill plug requires a 10mm male hex (allen head) wrench type socket for a 3/8" drive socket wrench.
GREAT suggestion to remove (loosen) the fill plug first!!!
I did it on mine a month or so ago and agree with the 2 posts above. You won't need a breaker bar. If I remember correctly the 3/8's extension I used will fit into the hole on the plug but I changed the fluid in 2 trucks an ss Camaro and the vette all around the same time so I could be wrong about that. I would be sure to re check the level after driving it around the block and I would take it easy for the first few miles to make sure you have lubricant everywhere it needs to be. The part number for the fluid is 88862624 GM fluid. Good luck.
It is rather tight to get your hand in there to turn the wrench on the fill plug. I found that dropping the stabilizer bar gives you enough room to get up there. The stabilizer bar can be left attached to the endlinks, just remove the 4 bolts holding it to the bottom of the car (2 per side) and let it droop out of the way.
........ If I remember correctly the 3/8's extension I used will fit into the hole on the plug but I changed the fluid in 2 trucks an ss Camaro and the vette all around the same time so I could be wrong about that.................
It has been several years ago since I did a C6 diff fluid change so you are more likely than me to be correct about this. The breaker bar isn't because you need the torque multiplication due to the longer length but simply to reach the fill plug with your hands low enough to exert some rotary force on the wrench.
BTW - I will be doing the ZR1 in the very near future. DEXRON LS sitting on the shelf now.
I had one of those plastic pumps and it broke on the third pump, so I drilled two holes in the diff. fluid bottle, one to fit the fill tube and one to fit a small plastic line to provide air pressure to the bottle. I used my small air compressor, with a hand control valve to control the air flow to the bottle, to apply air pressure to push the fluid down and out the fill tube into the differential. One caution, keep air pressure low so you don't overpressure the bottle. Since the fill tube goes to the bottom of the bottle, any leaks will just be air, so it is not as messy.
Air pressure on top of the fluid, forces it down and out the fill tube, so you are not actually having to pump the fluid out like with one of the hand pumps.
I did not have to raise the car at all to drain and refill the differential.
A drain plug wrench can also help.
Last edited by TEXHAWK0; Feb 17, 2016 at 11:57 PM.
I refilled the diff and swapped it again after 100 miles just to see what it looked like and it was much better. I have owned many Corvettes and never seen one this bad.
I refilled the diff and swapped it again after 100 miles just to see what it looked like and it was much better. I have owned many Corvettes and never seen one this bad.
Changing rear diff fluid - Tips please
