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Topic: Transmission Front Seal

in Forum: C3 Driveline Components


Transmission Front Seal

Posted: 2/20/05 9:32am Message 1 of 5
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Sterling Heights, MI - USA
Joined: 11/13/2003
Posts: 110
Vette(s): 1982 Collector Edition, color is silver/beige.
I posted this same inquiry last year and did not have much of a response. So....here I go again. I have a very small transmission leak. I cannot tell where it is coming from. Correct me if I am wrong but there are only five places where a transmission can leak if it is not damaged: Transmission pan, speedometer cable connection, shifter, front and rear seals. Anywhere else? I think it is from the front seal. How can I really verify this and if this is the problem, do you have to disconnect the transmission to replace it?.... which I believe you do?  C'mon, someone out there knows this. Thanks! 82CE38403.3978587963


Mike
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Transmission Front Seal

Posted: 2/20/05 10:08am Message 2 of 5
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sonoma, CA - USA
Joined: 8/9/2002
Posts: 784
Vette(s): 72 LT-1 AC coupe,69 l-36 coupe
If its the front seal you have to at least slide the trans back, pull the torq. conv. to replace fron seal, possible points of oil leaks, trans pan and loose bolts,oil pan surface not flat,extenson housing, loose bolts, rear seal,square seal ext. to case, porous casting,filler pipe o-ring, modulator o-ring,detent cable o-ring, governor cover not tight, speedo cable o-ring,manual shift seal,line pressure tap plug loose,vent pipe, front pump seal,seal lip cut, check conv. hub,bushings moved and damaged, oil return hole plugged, front pump attaching bolts loose or bolt washer seals damaged, front pump housing o-ring, oil leaks are generally carried towards the rear of trans by air stream,the use of a 'black light' to locate the point of the leak can be helpfull to determine if leak is eng. or trans oil, have fun.    anips38403.4300115741


Transmission Front Seal

Posted: 2/20/05 5:14pm Message 3 of 5
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20219
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
Whew!! anips pretty well covered it ! The best way to determine if the leak is at the front, is to pull the dust cover off the trans, and look up into the bellhousing area. If it appears to be leaking from the front, I would suggest spraying up inside the bellhousing with some brake cleaner, and get the area as dry as possible. Leave the dustcover off and cruise around for ten min. or so. Then check again. If the fluid is definitely coming from the front, you have no options other than pulling the trans. While it is out, it would be best to completely reseal the unit. That means pulling the pump and replacing the o-ring, gasket, seal, and bushing. The other seals; rear, speed-o,filler tube bootie, t.v.cable bootie, and pan gasket would complete the deal. The 700R4 trans is notorious for the pump o-ring 'shrinking', and also, the earlier units had a problem with the pump seal being forced out by too much fluid pressure , a byproduct of a worn pump bushing. There is a 'seal retainer' that comes on the later units to prevent the seal from popping out, and they are available at the dealer, or your locale tranny shop. I highly recommend installing one of these if you wind up pulling the trans. You want to do it all at once, and do it ONLY once!!! Make sure the converter hub is good, too, with no grooves that you can catch your fingernail on. If the hub is damaged, replace the TC: Not the time to save a few $$$ here!


Joel Adams
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Transmission Front Seal

Posted: 2/21/05 1:51am Message 4 of 5
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans

damn... i was going to add a list of a few items but looks like Joe (anips) covered more than i was going to list..

I definitely agree on rebuilding it if you pull it..  a good transmission shop is able to rebuild it better than when it came from the factory..

those early 700r4's had lots of problems..  the 700r4 has since become rock solid but it took some trial and error to get it there

 




Transmission Front Seal

Posted: 2/21/05 3:22pm Message 5 of 5
Former Member
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Sterling Heights, MI - USA
Joined: 11/13/2003
Posts: 110
Vette(s): 1982 Collector Edition, color is silver/beige.
Thanks a lot for the great input guys. I will pull the tranny and get her fixed up real nice by Spring.


Mike

in Forum: C3 Driveline Components


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