TH350 Torque converters: LT1 != LS1
Thread Starter
Staging Lane
Joined: Dec 2001
Posts: 93
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From: Houston, Texas USA
TH350 Torque converters: LT1 != LS1 This might be old as dirt info to some, but to the rest of us looking for an inexpensive route to converting to a TH350 tranny, it is extremely crucial you get a torque converter with an LS1 pilot, as they are not all created equal!
The pilot size and length of a TH350 TC sitting behind an LT1 motor is very different than that of one sitting behind an LS1.
I bought a TH350 and TC setup from a friend who had it in his LT1 Camaro, and installed it in my LS1 Trans Am, thinking it would simply bolt right up. Well, it did just bolt right up, but that's not good enough for the TC.
Evidently, I was lucky in that I got the TC aligned pretty true at first, but eventually, my motor developed a vibration problem that progressively got worse and worse.
For the life of me, I could not figure out where it was coming from, until I unbolted the TC from the motor and the vibration went away. Thinking it was just a bad TC (which in fact it did have a failed bushing inside - probably due to being misaligned), I replaced it with another one (also not specifically built with an LS1 pilot), but the vibration returned. Boy, talk about a head scratcher!!
I was talking with a tranny guy here in Houston who has built many many bullet proof TH350's (Ronnie at Century Automotive), and he suggested I call Precision Industries and verify the TC I had just ordered was built with an LS1 pilot. Sure enough, it wasn't. The correct one is on the way now.
Here's hoping others don't have to learn the hard way like I did.
The pilot size and length of a TH350 TC sitting behind an LT1 motor is very different than that of one sitting behind an LS1.
I bought a TH350 and TC setup from a friend who had it in his LT1 Camaro, and installed it in my LS1 Trans Am, thinking it would simply bolt right up. Well, it did just bolt right up, but that's not good enough for the TC.
Evidently, I was lucky in that I got the TC aligned pretty true at first, but eventually, my motor developed a vibration problem that progressively got worse and worse.
For the life of me, I could not figure out where it was coming from, until I unbolted the TC from the motor and the vibration went away. Thinking it was just a bad TC (which in fact it did have a failed bushing inside - probably due to being misaligned), I replaced it with another one (also not specifically built with an LS1 pilot), but the vibration returned. Boy, talk about a head scratcher!!
I was talking with a tranny guy here in Houston who has built many many bullet proof TH350's (Ronnie at Century Automotive), and he suggested I call Precision Industries and verify the TC I had just ordered was built with an LS1 pilot. Sure enough, it wasn't. The correct one is on the way now.
Here's hoping others don't have to learn the hard way like I did.
