93 Chev. C-3500

[terry]

A friend of mine came over with a problem with his 93 Chev. C-3500 dually 6.5 L diesel . It will not shift into OD. The rpm's stay high at cruising speed above 55 (around 2500) but it will not drop down. He told me that a week prior to this it had lost power. NO cranking, dead batteries. He got it going again but now no overdrive. I checked the TPS with a VOM and it showed good. Checked all related wiring and fuses and everything looks ok. I believe this has a 4L60-E in it. Has anyone ran into this before? Not sure where to look next. Would appreciate any ideas. Thanks,
Terry

 

[crunch]

Fluid level and fluid condition?
All fuses good?
Has it lost lock up or 4 th gear or both
Good time to get it on a transmission and engine capable scanner and see what is going on.
read out data and check for engine or transmission codes.
post back any codes no.

 

[Transman]

It also would not hurt to check the engine data, make sure the engine temp is rising, not just the real temp which is important but also the sensor that tells the computer what temp the engine is running. Post back with any codes and data you come up with, Transman