I have a 77 auto and need to change the transmission fluid. Can anyone tell me what type of a job this is to do myself and what I need. Also, is it a good idea to change the rear end fluid and how would I do that? Thanks everyone for your help, I appreciate it!
Vette(s): 1981 dark metallic blue, dark doeskin leather interior, mirrored glass T Tops, 330hp/350ci GMPP crate engine, billeted aluminum serpentine system, Dewitts with dual spalls
The transmission is pretty straight forward, but messy. You will probably have to drop the entire pan. I am not sure if you have a drain plug. I would recommend one of the large flat aluminum pans plus the plastic pan to catch the fluid. The aluminum pan is for what does not make it into the plastic pan, otherwise you could be laying in a large spill, plus the clean up of the surface. You will probably have to change the gasket and you should also change the filter while in it.
The rear diff is a different animal. I did mine, but don't remember. I totally rebuilt the diff and had it out of the car. I am certain Joel, Adams' Apple will kick you with the scoop.
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
"Kick"! Changing the trans fluid is pretty straightforward. As mentioned, get a LARGE drainpan!. Remove all of the bolt around the front, and sides of the pan...leave the ones on the rear until last. With the front/sides loose, if it hasn't already started draining, give the pan a little love-tap on the sides to break it loose. Let it drain as long as you can. Once it's down to a trickle, loosen the rear bolts, and slowly let the front of the pan hang down. Remove all but 2 of the rear bolts at this point. Once you have as much fluid out as you can get, hold the pan up with one hand, and remove the remaining bolts. Clean the pan, and change the filter. If you have a 400 trans, replace the o-ring on the tube that the filter fits onto. The o-ring may stick up in the case, but make sure it gets changed. (There is no o-ring on the filter end) If your's is a 350 trans, the filter will have the word "Front" embossed/printed on it. Pay attention to that, as the filter can be installed backwards! Clean the pan rails, and the case where the pan seals very well. The cleaner it is, the less chance of it leaking. Don't use any sealer, or silicon on the gasket!! Most pan gaskets have smaller holes where the pan bolts go, so the gasket is held to the pan by the bolts, making it easier to install, and there is no other reason for using a sealer of any kind. The use of silicon(RTV), or any other sealant can cause the gasket to slide out, creating a leak.
As far as the diff, the only way to change the gear lube is to suck it up...or out, of the fill hole, with a suction gun. You can get this at most parts houses. There are aftermarket drain plug kits for the diff, if you want to make the job easier next time. hth
____________________________________ Joel Adams C3VR Lifetime Member #56 My Link
I'm no expert on the trans but I do have some recent experience with the rear diff. fluid change.
First, I added some GM Positraction Additive. Then I drove it to let it work in to the clutch packs in the diff. Then I used a hand pump and got out all the fluid I could. Lastly I added the new Rear End Axle Lube and more Posi. Additive. I did it twice.
I think it's a good idea to pump it out twice like that and finish up with new fluid and additive.
It may sound overdone but it saved me from having to have the rear diff. rebuilt.
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