Discussion in 'GMC Truck Forum' started by gmcer, Apr 13, 2005.
I just had this same problem, it is the trans cpu module. The part is around $150.00.
Friend with the same year truck has gone through 3 tranny's just driving....
have a '99 GMC Z71 w/ 200K miles. was out putting out some political campaign signs and tranny started shifting really hard, thought it would jump out the chasis. did it several times, then stopped for gas, restarted and drove off like nothing had ever happened! stopped at dealership and they said that if there was no message on the trouble screen in the dash then there was no reason to check for any codes? days later stopped for coffee and when I tried to pull off truck would barely move. stopped, shut it down, waited ~30 sec. and restarted engine and then pulled off like nothing ever happened.
someone mentioned a "cpu" what and where is it??
Sounds more like shift solenoids
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