transmision question

[tron1989]

The torque converter in my 2001 2500HD will not always lock up once in overdrive. Especially at highway speeds. At highway speeds the torque converter lock in for about 20 seconds and right back out again and the cycle continues while driving. During city driving it locks in usually at 45 mph. But if I am onthe accelerator hard it take longer for it to lock up. The transmission shop could not find anything wrong, but did note the condition. There are no codes fromthe computer.

[MT-2500]

Originally Posted by tron1989

The torque converter in my 2001 2500HD will not always lock up once in overdrive. Especially at highway speeds. At highway speeds the torque converter lock in for about 20 seconds and right back out again and the cycle continues while driving. During city driving it locks in usually at 45 mph. But if I am onthe accelerator hard it take longer for it to lock up. The transmission shop could not find anything wrong, but did note the condition. There are no codes fromthe computer.

Could also be a engine running problem.

Get it on a good engine transmission capable scanner and check both engine and transmission.
Is the engine running at full power?
Engine has to be running good for transmission to work right.
Let us know what you find on engine running.

[j cAT]

Originally Posted by tron1989

The torque converter in my 2001 2500HD will not always lock up once in overdrive. Especially at highway speeds. At highway speeds the torque converter lock in for about 20 seconds and right back out again and the cycle continues while driving. During city driving it locks in usually at 45 mph. But if I am onthe accelerator hard it take longer for it to lock up. The transmission shop could not find anything wrong, but did note the condition. There are no codes fromthe computer.

If the vehicle has no drive train DTC or engine DTC if you lucky the maf maybe dirty.. this can mess up the transmission shift operation. the other item may be the brake switch . when hitting the brakes the lock up cuts out.

use CRC MAF cleaner only and follow the directions on cleaning the MAF..

If you see no changes could be worn transmission componets.

[tron1989]

Thanks

[kahjdh]

Wheres the transman when you need him,

Idk if the 4l80 is the same as the 60 when it comes to the tcc solenoid and valve setup but they have been known to wear out. There are updated parts available for these.

[transman618]

Did they monitor the TPS?? This is the most common problem with TCC's falling in and out of lockup. It doesnt have to set a code, all it needs is a brief spike which is usually caused by a faulty TPS or from electrical noise from the alternator. The shop needs to drive the vehicle with a scanner attached and monitor TPS and TCC activity.


transman

[kahjdh]

There he is!

This guy knows what he is talking about.

[tron1989]

Originally Posted by kahjdh

Wheres the transman when you need him,

Idk if the 4l80 is the same as the 60 when it comes to the tcc solenoid and valve setup but they have been known to wear out. There are updated parts available for these.

Thanks