Upgrades for TH350?
07-22-2002, 09:59 AM
#1
Member
Thread Starter
Join Date: Apr 2001
Location: Fresno, Ca
Posts: 138
Likes: 0
Received 0 Likes
on
0 Posts
Upgrades for TH350?
I'm in the middle of swapping out the 700R4 in my '85 Corvette to a TH350. The 700R4 has proven to be far too unreliable for my application. It was fine for the stock motor, but with my current motor, I'm replacing trannies far too often. I've found a core TH350 that I plan to build for the car. What upgrades are recommended to the TH350?
07-22-2002, 04:29 PM
#2
Senior Member
Join Date: Jun 2001
Location: FL
Posts: 639
Likes: 0
Received 0 Likes
on
0 Posts
As far as internal mods go wider bushing in certain locations are a common upgrade, a hardened intermediate roller clutch race, tightened clutch clearances.
As far as shift kits go most seem to do the same thing, yes I said it, transgo, b&m, etc all seem about the same for a th350. I have tried both of them and I'm currently using a superior products kit. It's a little cheaper than most and requires installation during a rebuild.
Just don't get the cheaper b&m kit get one with a seperator plate AND springs.
The book on th350's by ron sessions is a good guide.
As far as shift kits go most seem to do the same thing, yes I said it, transgo, b&m, etc all seem about the same for a th350. I have tried both of them and I'm currently using a superior products kit. It's a little cheaper than most and requires installation during a rebuild.
Just don't get the cheaper b&m kit get one with a seperator plate AND springs.
The book on th350's by ron sessions is a good guide.
07-24-2002, 05:23 AM
#4
Supreme Member
Join Date: Jul 1999
Location: Calimesa, California, U.S.
Posts: 3,458
Likes: 0
Received 39 Likes
on
27 Posts
I have built hundred's of TH350's and the only kit that gives long life & performance is the Trans-Go Performance Shift kit. There are many things that can be done to improve the life of this unit. (1) start with a late 1970's TH350 core (one that has the needle bearing on the front pump where the direct drum rides), (2) use teflon sealing rings on the stator, (3) machine direct piston so you can have 5 clutches, (4) use the plastic input to output shaft seal for better lubrication to the rear planet, (5) use bronze rear case bushing, (6) use the later wide low/reverse sprag from the 700R4 (1988 & up), (7) use the teflon extension housing bushing, (8) leave in the 2nd gear waved steel (prevents sprag race breakage), (9) use the 3-tang waved in the forward pack, (10) install the extra wide bushing in the direct drum, (11) a good used 2nd gear race with little wear will work fine, (12) "DO NOT" block any accumulators, (13) use cast iron rings on all accumulators & 2nd gear band apply piston, (14) use reinforced (welded) red-lined (no kevlar) 2nd gear band, (15) setup up direct clutch clearance at .070-.090, (16) use the low drag turbulator steels in the low/reverse pack (1996 & later 4L60E), (17) reduce the 2nd gear clutch clearance to .040, this will prevent a 1-2 manual shift delay, (18) use the TH350C filter (dacron) along with a pan magnet, (19) use Borg-Warner clutches everywhere, unless you have a high HP unit then use the Alto Reds in the direct pack "only". This should give you some ideas on what to do and what works for this unit. Use a good Dexron III oil.
Thread
Thread Starter
Forum
Replies
Last Post
