97 suburban - hard shift from 1st to 2nd

I have a 97 suburban 4x4 5.7L automatic with about 145K miles on it. After running at highway speeds for about an hour and pulling off at an exit ramp I run into the following problem. When starting back up from a stop, I get a loud clunk when the trans shifts from 1st to 2nd gear. There is a jerk that throws your head back slightly also. This only seems to happen after running at highway speed for a while. While driving in normal city traffic it shifts very smoothly. Any Ideas?

I had the same problem a couple of years ago, sadly at 80,000 mi.

I had to have the transmission rebuilt. Basically, what's happing is that the transmission is "overheating", which causes the electronic trasmission in the '97 Sub to quit working. It's been fine ever since.

However, you may also notice in the near future, if you don't get it fixed, that you'll be crusing along on the highway, and suddenly, for no reason, the truck will "downshift" - the RPMs will get really high, and the engine will rev. This is the electronic transmission on it's last legs.

Sorry for the bad news, but you'll need to get it rebuilt or replaced - cost me about 2500.00!

Good luck!

I have a 97 suburban 4x4 5.7L automatic with about 145K miles on it. After running at highway speeds for about an hour and pulling off at an exit ramp I run into the following problem. When starting back up from a stop, I get a loud clunk when the trans shifts from 1st to 2nd gear. There is a jerk that throws your head back slightly also. This only seems to happen after running at highway speed for a while. While driving in normal city traffic it shifts very smoothly. Any Ideas?
You might try replacing the fluid and filter. Always worth a try before the big bucks.

I have a 97 suburban 4x4 5.7L automatic with about 145K miles on it. After running at highway speeds for about an hour and pulling off at an exit ramp I run into the following problem. When starting back up from a stop, I get a loud clunk when the trans shifts from 1st to 2nd gear. There is a jerk that throws your head back slightly also. This only seems to happen after running at highway speed for a while. While driving in normal city traffic it shifts very smoothly. Any Ideas?


It is most likely a worn valve body and it is very common. There is pluger for the lockup that gets worn and hangs up. When this happens the computer senses slippage and raises the trans pressure to compensate and this causes the hard shift. The valve body can be reworked for around $300.00-500.00, But with that many miles it may need to be rebuilt especially if it does it a lot and you keep driving it. Next time it does it shut the truck off and restart it because most of the time it will work for a little while otherwise put it in drive or it will burn up the torque converter. There was a recall on the 97's for a ground wire on the trans and if that wasn't done it could also be the problem.