Regular Th350/Th400 TC fit a TH350C?
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Joined: Aug 2005
Posts: 3,004
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Regular Th350/Th400 TC fit a TH350C?
I think i may have asked this way back in the day, but cant find the thread or recall the answer.
As some of you may know i have the wacky TH350C tranny. Due to my geographical location im pretty hard pressed to find any used trannys, and when i do they arent in the best looking shape...
I have no use for the lockup on this thing, never had or never will wire it up....
Im looking to find a higher stall TC for this thing but cant find anything other than a custom built unit for a th350c!
I hear the 350c is the exact same case as the regular 350, would i be able to swap the input shaft from a regular 350 and then use a regular 350 TC?
As some of you may know i have the wacky TH350C tranny. Due to my geographical location im pretty hard pressed to find any used trannys, and when i do they arent in the best looking shape...
I have no use for the lockup on this thing, never had or never will wire it up....
Im looking to find a higher stall TC for this thing but cant find anything other than a custom built unit for a th350c!

I hear the 350c is the exact same case as the regular 350, would i be able to swap the input shaft from a regular 350 and then use a regular 350 TC?
Thread Starter
Supreme Member
Joined: Aug 2005
Posts: 3,004
Likes: 4
From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Yep, still looking.
The lockup is exactly why im looking to convert this thing to non lockup guts. I cant find ANY half decently priced TC's for this tranny.
I dont care if the TC had lockup guts or not, its not functional anyways. I just need a 3k stall TC to fit this input shaft!
The lockup is exactly why im looking to convert this thing to non lockup guts. I cant find ANY half decently priced TC's for this tranny.
I dont care if the TC had lockup guts or not, its not functional anyways. I just need a 3k stall TC to fit this input shaft!
Joined: Sep 2005
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If you want to run a non-lockup converter, you need a non-lockup transmission (no "C"). That's about all there is to it.
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From: 62656
Car: 1991 S10 pickup 2700lbs
Engine: 4.3L Z TBI
Transmission: 700R4
Axle/Gears: 3.08 7.625"
i ahve the same problem as you do, i have a 9" tail th350C from an 81 c-10 pickup that had the factory available oldsmobile diesel 350 engine, it has the 10 bolt universal bellhousing pattern
well heres pics of it:


i have no converter for it since i had to junk the diesel one since they are a lower stall speed than gas engines can run with and ive had this tranny sitting in the basement on a bucket for a couple years waiting to find a gas lockup converter, all to no avail thus far yet
perfectly good tranny though
it seesm to be imposible ot get a straight answer on whether the tranny woudl run fine without the lockup feature used and with a non C input shaft swapped in it
i wish someone knew for sure
if it would be fine then this is the route i would go with my c model 350 trans too
so i can finally use it in something
good luck
well heres pics of it:


i have no converter for it since i had to junk the diesel one since they are a lower stall speed than gas engines can run with and ive had this tranny sitting in the basement on a bucket for a couple years waiting to find a gas lockup converter, all to no avail thus far yet
perfectly good tranny though
it seesm to be imposible ot get a straight answer on whether the tranny woudl run fine without the lockup feature used and with a non C input shaft swapped in it
i wish someone knew for sure
if it would be fine then this is the route i would go with my c model 350 trans too
so i can finally use it in something
good luck
Last edited by Randy82WS7; Mar 12, 2007 at 10:08 PM.
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Supreme Member
Joined: Mar 2002
Posts: 4,812
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From: 62656
Car: 1991 S10 pickup 2700lbs
Engine: 4.3L Z TBI
Transmission: 700R4
Axle/Gears: 3.08 7.625"
Re: Regular Th350/Th400 TC fit a TH350C?
ok thanks yeah im interested in how much for a stock speed one, and and how much for a 12 or 1500 stall one ?
i sent a pm too
thanks
i sent a pm too
thanks
Thread Starter
Supreme Member
Joined: Aug 2005
Posts: 3,004
Likes: 4
From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Re: Regular Th350/Th400 TC fit a TH350C?

I really dont care if it does or doesnt have the lockup guts in it, im not hooking up the lockup so i figured why pay for the extra junk if i dont need it?

87rock, ill shoot ya a PM. Ill probably be looking for one that stalls around 2-2500.
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Joined: Sep 2003
Posts: 248
Likes: 4
From: SE AZ
Car: 1990 Corvette, 1985 C-10 1979 Subun
Engine: 350, 406 HSR
Transmission: manual, 200 4r
Re: Regular Th350/Th400 TC fit a TH350C?
Besides the input shaft differences on the 350 and 350c there is is also different parts on the valve body. On the 350c there is an aux valve body installed that handles the lock up clutch. Also the pump is different between the lockup and non lockup.
You can purchase a higher stall lockup TC and then not use the lock up function. Check ebay and look for Oregon transmission parts, they have them at around $110 US.
But it has been discussed that not locking up the TC can produce excessive heat in the fluid which is very bad for the trans.
I have never tried to install a non lockup TC on a lockup trans. so I can't answer that one. Just looking at the differences in the input shafts would lead me to believe that you can't do it.
You can purchase a higher stall lockup TC and then not use the lock up function. Check ebay and look for Oregon transmission parts, they have them at around $110 US.
But it has been discussed that not locking up the TC can produce excessive heat in the fluid which is very bad for the trans.
I have never tried to install a non lockup TC on a lockup trans. so I can't answer that one. Just looking at the differences in the input shafts would lead me to believe that you can't do it.
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