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what transmission do I have?

LanceB

Well-known member
Joined
Jul 18, 2003
Messages
455
Location
Louisville
Corvette
1981
It is a 77 L-82 3 speed auto. I need to replace filter and gasket. All I see under it is Hydra-matic written on the oil pan can't find anything else yet to identify it....leaking like crazy.
 
B

bmotojoe

Guest
I would think it is the TH-350 but you can tell by the pan. The TH-350 and TH-400 are different shaped. The link below when it opens shows the pan gasket and filter of the TH-350. Just to the right on the same page there is a smaller picture of the TH-400 filter gasket kit so you can see the differance in the pan shape between the two right away.
http://www.ecklers.com/product.asp?pf_id=A3482&dept_id=1852
Brian
 
B

bmotojoe

Guest
Seems like Ecklers site is having a problem on and off this morning.
Brian
 

LanceB

Well-known member
Joined
Jul 18, 2003
Messages
455
Location
Louisville
Corvette
1981
Thanks for the help, definitely a 400 looking at the pan. Wonder if I can get a gasket and filter at autozone or needs to be ordered. Do you know what the difference is between a 350 and 400 transmission?
 
B

bmotojoe

Guest
I bought a filter gasket kit from a local parts house and bought a A/C delco filter gasket kit from the dealer and now I only use the A/C delco kits. The reason is because the gasket material and filter are far superior to the aftermarket ones IMO. The holes in the pan gasket of the A/C delco are made so you thread the pan bolts through the gasket so the gasket then fits nice and flat exactly where it should. I never had a problem using OEM parts when I can. Remember to torque the pan bolts evenly at 130 inch pounds or 11 foot pounds each.
Not sure what is the difference between the TH-350 & TH-400 but it all depends what there used for, like pulling I know that the TH-400 is a stronger unit but for building a race transmission I have heard that the TH-350 is better suited for that.
Brian
 

LanceB

Well-known member
Joined
Jul 18, 2003
Messages
455
Location
Louisville
Corvette
1981
Found at Autozone, tight fit. Looks like I overfilled fluid tho. It was showing way low, then poured 1/2 quart in, now way over the circle on the dipstick. can't believe no drainplug. Guess I will loosen bolts and drain some out.
 

KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Found at Autozone, tight fit. Looks like I overfilled fluid tho. It was showing way low, then poured 1/2 quart in, now way over the circle on the dipstick. can't believe no drainplug. Guess I will loosen bolts and drain some out.

I think B&M has a TH350 and a TH400 pan with a drain plug.

In fact, if you go over to Street and Strip off Prestin Highway, Drew Tarr may even have one in his shop.
 

LanceB

Well-known member
Joined
Jul 18, 2003
Messages
455
Location
Louisville
Corvette
1981
I am just going to loosen the pan and drain a little bit to get the excess. Would like to just install a new pan, but just going to make do. It would be nice though. I am second guessing the filters tightness. I connected it with the inlet and lined the single bolt up and tightened it, the inlet looked tight also, but the filter itself still felt like it had a little play in it. I examined the single bolt for the filter and it had a sizeable unthreaded portion, so I just attributed it to that. Maybe I didn't check the fit of the filter I removed well enough. Does anyone know if that sounds like the way the filter is mounted? I got my 81 out today. Beautiful day in Louisville, saw at least 5 other Vettes when I was out cruising. I think I am changing the transmission gasket and filter on the 81 next.
 

AKRAY4PLAY

Well-known member
Joined
Oct 14, 2001
Messages
584
Location
Wasilla, Alaska, U.S.A.
Corvette
'77 L-82, black on black. Full mod 406 small block
the big difference in the TH-350 and TH-400 trannies are the amount of power they can take. the TH-400 is one of the most bullet-proof trannies out there, extremely stout. the TH-350 is still strong, but does not hold a candle to the TH-400. now the big upside of the TH-350 is lighter weight. this is manifested in two ways, lighter total car weight and less rotating mass. lighter rotating mass allows the engine to spin up faster and easier, and of couse lighter total weight means less car to get moving. both contribute a better drag racing numbers for the TH-350, until you start making enough power to that the TH-350 gives up the ghost. either tranny in a stock car will last forever. as for filters and replacement parts, ANY parts supplier will have tons of parts for both trannies. these are the most successful trannies GM fielded and there are litterally millions on the road.
 

LanceB

Well-known member
Joined
Jul 18, 2003
Messages
455
Location
Louisville
Corvette
1981
If anyone could read my above post about the play my trans filter seems to have, that would be great. It is on as tight as it will go.
 

Phill

Well-known member
Joined
Apr 20, 2007
Messages
216
Location
s.florida
Corvette
1979 Blk L48
if you used an aftermarket kit i would buy and install an ac delco kit. i did my 350 with an original kit and didnt notice any play in the filter.
 

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