Hey guys. I just bought my first C3, a 1979 4-speed. I set
out to replace the transmission output shaft seal and have run into a hiccup. I
have the old seal removed and all the fluid drained, but no matter what I try I
canít get the new seal to seat. I donít have a lift and Iíd like to avoid
taking out the transmission if I can, but since the shaft is sticking out I canít
hit the entire seal at the same time. As you might guess, this is my first time doing this procedure on any car.
I made up a block of wood with a hole in the middle sandwiched
between two pieces of metal, and hit it with a 3lb mallet, but I canít get
enough momentum on the garage floor to smack the seal hard enough to seat it. I
canít walk it in by tapping the perimeter, because as I tap the opposite side pops
out. The only race press hand tools I can find are flat and won't work because of the output shaft.
The only forum posts I can find about replacing an ST10 (or
any) output shaft seal just say ďand then put the new seal inĒ. Iíve also read where
people say removing the transmission is not required. I feel like this is supposed
to be done with a machine press. That, or installing this seal is knowledge known by mechanics
and not the internet. Any help is appreciated!
Vette(s): 1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.
A "DEEP" 1/2 or 3/4 inch drive socket that is the exact diameter of the seal should work. You have to drive it square, as you know it pops out with uneven pressure. A new seal MAY not be the ticket if surfaces on the inside of the tail shaft are worn to much.
agreed with manchestershark, get a socket thats the same outer diameter of the seal, or even a short piece of pipe, an old bearing race....anything that is the same diameter of the steel cup of the seal, anything to give yourself room to hit without hitting the output shaft.... i know room is tight under there, but you Might have to take the transmission mount off (jack up the transmission to remove it, thinking its 2 bolts on the transmission, and 2 on the crossmember, unless your crossmember is removable, then you could unbolt the crossmember and lower the back of the transmission while its bolted to the engine) this will give you a little more swing room...just keep the transmission supported(keep the jack under it and lifted a little) so it doesn't stress the motor mounts too much. Might give yourself a few inches more to work with.... but i would start with it together first, then resort to lowering it if needed....
and sometimes it does take a few good hard whacks to get it started..take a little motor oil and coat around the outer of the seal, and make sure the output shaft housing is smooth and no burrs, and a little oil there would not hurt either....oh and oil the lips and output shaft too, you do not want those dry when it first spins up....
StingrayJim NCM Lifetime Member #1936
Stingray's '76†††††††††††††††††††††††††††† StingrayJr's '78†††††††††††††††††††††††††††Lil Red '94 (click each one to see a bigger version)
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
Chances are your seal is already damaged, but if not, take it to your local Autozone/Orielly's/etc and see if they have a "loaner" seal driver for it. If not, check Harbor Freight or Northern Tools.....they usually have a cheesy set of drivers that work for occasional use. The driver will set inside the seal to hold the spring in place while you knock it into the housing. Done right, one good whack is all it takes. Be sure to pack some heavy grease into the void on the backside of the seal to help hold the spring in place, because if you knock the spring out installing the seal, it's gunna leak even worse than it was before.
____________________________________ Joel Adams C3VR Lifetime Member #56 My Link
I damaged the first seal. Good thing these are only $7!
I bought a driver set from Harbor Freight when OíReilly didnít
have any, but theyíre flat unlike the one in that image. I also tried using a 2Ē
long piece of exhaust coupling equal to the width of the inner surface of the seal, but to no avail.
My transmission crossmember is fixed, so at best moving the transmission around might get me 1-2 extra inches to work with. I'm not in a position to create a removable crossmember.
I'm just not seeing a way to get enough of a swing to seat the seal. There's too much in the way, the garage floor included.
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