4l60e tranny lock up questions?

[Tim Cucci]

This may be off topic but I know this is the place to get the right answers.
97 Chevy 2WD pick up truck. I am trying to sell it.
I have a guy that wants to buy it but he is saying that the TC is not locking up. I have never noticed any type of problem.
At 60 MPH the truck turns 1750 RPM while cruising.
At 70 MPH the truck turns around 2000 RPM.
WE did the brake tap test at 60 and nothing happens and that is what this guy swears by for TTC lock up.
How can I really tell if the convertor is locking up?
Thanks
Tim

 

[Otto J]

On a 97 vehicle it should set a code if it is not locking up. Also those models have a Pulse Width Modulated torque convertor clutch so it is not always applied 100%. Best to check car with a scan tool for any torque convertor related codes, THey wont alway kick the SES light on.
THese trannies are known for having lockup problems related to worn valve bodies.
It will set a code p1670 if it is not working
Hope this helps
Otto

 

[Tim Cucci]

Thanks for the help. I didn't think it was as simple as a brake tap like our TR's. The truck is locking up and it is very hard to tell but after some real particular test driving and paying attention you can tell. I sold the truck to this same guy after he had talked to some people a tranny shops. They also said that if the tranny is not locking up it should set the code. That was the first thing they asked. Thanks again for the help and sorry about being off Buick topic but this is the best place to go for any tranny problem.

Thanks
Tim

 

[Otto J]

No problem, It a tranny help section and its a tranny
So ask away