Playin' the tail...
Thread Starter
Teching In
Joined: Sep 2004
Posts: 40
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Playin' the tail... Okay, fine - lame attempt at a play on words. Here's the deal - and bear with me, cuz it's kindof a long story...
I bought a '69 GTO last summer (yeah, I know it says "LS1-Tech", but the car is inconsequential - my question is about the TH-400 tranny it's got). The guy said that he had just put a transmission in it and that it was good to go, and it seemed that this was the case when I drove it.
A few months later, I started noticing a cyclical vibration at highway speeds. It turned into a bit of a shudder at most speeds, followed by a VIOLENT shudder at ANY speed. All the while, I'm chceking u-joints, replacing fans and water pumps, contemplating engine balancing, the whole nine. When it gets so bad that I can't ignore it anymore, I get under the car to figure it out once and for all. Lo and behold (and get this), the TRANSMISSION IS COMING OFF OF THE ENGINE!!!!
I know, right? Rediculous. Apparently, when the guy replaced the tranny, he forgot to tighten the bolts. The vibration/sound I was hearing was the transmission banging againt the engine block. Two of the six bolts were missing, two were broken, and the remaining two were loose. SO, I fixed all that, and everything was good for a while. Smooth as glass. Then I notice a small vibration developing again, and promptly check the orientation of the transmission relative to the engine (I'm a fast learner). Everything's tight (of course - I tightened them myself). I get under it again, and check the u-joints. THEY seem fine, but the front yoke has what seems to be abnormal play within the tail housing. Closer examination reveals that the seal back there has been leaking. Not a WHOLE lot, but enough to raise an eyebrow.
So it seems to me that the 3 or 4 thousand miles I put on the car while I was getting that original "vibration" went a long way to seriously screwing something up in the a$$ end of the transmission. Do any of you who know what's up with 400 transmissions have any idea what the problem might be? Is it likely that I'll be able to do something about it without having to pay for a rebuild or major parts? Where do I start?
Thanks,
Zac
I bought a '69 GTO last summer (yeah, I know it says "LS1-Tech", but the car is inconsequential - my question is about the TH-400 tranny it's got). The guy said that he had just put a transmission in it and that it was good to go, and it seemed that this was the case when I drove it.
A few months later, I started noticing a cyclical vibration at highway speeds. It turned into a bit of a shudder at most speeds, followed by a VIOLENT shudder at ANY speed. All the while, I'm chceking u-joints, replacing fans and water pumps, contemplating engine balancing, the whole nine. When it gets so bad that I can't ignore it anymore, I get under the car to figure it out once and for all. Lo and behold (and get this), the TRANSMISSION IS COMING OFF OF THE ENGINE!!!!
I know, right? Rediculous. Apparently, when the guy replaced the tranny, he forgot to tighten the bolts. The vibration/sound I was hearing was the transmission banging againt the engine block. Two of the six bolts were missing, two were broken, and the remaining two were loose. SO, I fixed all that, and everything was good for a while. Smooth as glass. Then I notice a small vibration developing again, and promptly check the orientation of the transmission relative to the engine (I'm a fast learner). Everything's tight (of course - I tightened them myself). I get under it again, and check the u-joints. THEY seem fine, but the front yoke has what seems to be abnormal play within the tail housing. Closer examination reveals that the seal back there has been leaking. Not a WHOLE lot, but enough to raise an eyebrow.
So it seems to me that the 3 or 4 thousand miles I put on the car while I was getting that original "vibration" went a long way to seriously screwing something up in the a$$ end of the transmission. Do any of you who know what's up with 400 transmissions have any idea what the problem might be? Is it likely that I'll be able to do something about it without having to pay for a rebuild or major parts? Where do I start?
Thanks,
Zac
