ok guys I have a 1991 b2600i 4x4 with and automatic trans. owned this truck for years without trans problems. started randomly not taking off in first gear and sometimes wouldn't upshift. It would usually start shifting after driving it a short distance then it would be fine until you shut it off and let sit a while. then one day I drove it 15 miles before it finally shifted. changed fluid and filter--no debris in pan. added lucas trans treatment. Didn't help. Removed valvebody and sent it to be checked. they found a valve bore that had problems. they rebored the body and installed a sleeve in it. reinstalled valvebody. trans worked great for 20 miles. stopped to get gas and now its not shifting again. starts off in 2nd gear--no upshift. anyone else had this problem? thanks

 

I have a similar issue with my ‘92 b2600 A/T and will not upshift or downshift from second gear, I have also noticed that HOLD SYSTEM button will not illuminate on cluster. I had TCM repaired and issue still exists. Any suggestions anyone?

 

I also sent the TCM for repair. No help. Installed used transmission from eBay. Same issues. Purchased Mazda service manual and checked all wiring. No help
purchased used truck with 5 speed system. Changing my truck to manual transmission

 

Any info on how to test the TCM or which equipment is needed? I am looking into a rebuild, but want to see if it’s an electronics issue before getting into bigger expenditure.