95 6.5 turbo shifting problem after motor swap

[Rhummer]

I replaced my blown 6.5 this past weekend and have an issue with shifting into overdrive. Truck runs fine, temp is good 1,2,3 shifting is fine. Check engine light comes on with code "15" (coolant sensor" and it doesn't always shift into overdrive. I replaced the coolant sensor and still get light after driving a few minutes. Resets when I turn truck off. The interesting thing is when it finally shifts into "overdrive: the check engine light lights when it shifts. Code "15" again. Turn the truck off and on - no light. Drive truck and after a few minutes or miles it shifts into overdrive and the check engine comes on at the same time, code "15".

any help is greatly appreciated.

Chip

[DmaxMaverick]

Welcome aboard!

The shifting you are getting is "normal", according to what the PCM is translating. It won't shift into OD at lower speeds if it thinks it's too cold, and the torque converter won't lockup. Are you sure it isn't shifting into OD, or could it be the TC isn't locking?

The DTC 15 indicates the coolant temp is out of the acceptable range for the PCM. Either the sender is bad, not connected, or the circuit is open (poor contact or broken wire somewhere). Check for continuity from the sender to the PCM. Also, the 95 has 2 temp senders. Which one did you replace?

[Rhummer]

Thanks for the quick reply, I replaced the sender on the drivers side. Front right below the valve cover behind the power steering pump. I was not aware of another sender. Where is it located?

Chip

while I was messing around with my truck I noticed that the "check engine light" comes on right before it shifts into OD. It shifts in the mid 40's and runs 2000 rpm.

[Rhummer]

Update:

Found the other sending unit and was not plugged in. Plugged in and works great!

Thanks for the help

Chip