GMC Repair: 1997 GMC 1500 4x4, gmc 1500, autohelp


Question
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Followup To
Question -
When my truck is driven about 15 miles it goes to shifting very hard. If I stop and cut off for a few minutes it will shift smoothly until I go about 15 or so miles. And I mean it shifts hard.
What is the problem?
Answer -
I need more information. Answer these questions for me:

Naturally the vehicle starts out in 1st gear.

Does the hard shift occur during ALL shifts ?.

OR does it occur:

1. From FIRST to SECOND ?.

2. From SECOND to THIRD ?.

3. From THIRD to FOURTH ?.

4. From FOURTH to FIFTH ?.

The hard shift occurs at every shift after about 15 minutes of running.

autohelp

Answer
What was the LAST repair on the vehicle ?. ANY repair of any nature ?. In most cases problems that arise days, weeks or even months later can usually be traced back to the previous repair.


OK, Depending upon what MODEL trans you have,You could have several possibilities:

1. A mis-adjusted THROTTLE VALVE CABLE located at the throttle plate next to the gas pedal linkage.

2. A stuck THROTTLE PRESSURE VAVLE (pressure regulator)
  within the trans.

3. Faulty SOLENOID(S) within the trans.

4. A faulty PRESSURE PACK SWITCH within the trans.

3. A faulty/Stuck GOVENOR.

There are several other possibilities, But The vehicle needs to be driven to FEEL how it is shifting in order to make a PROPER diagnosis.

Be CAREFUL when you take in in for a diagnosis, As alot of facilities will try and sell you a REBUILD or REPLACEMENT  for the transmission at a cost of $1800.00 or MORE, When the fault may be a simple $50.00 part.

Out of curiosity, What state do you live in ?.


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