I'm looking for help on my transmission issue. I have a 4.8l and 4l60e from a 2000 chev 1500 2wd swapped into a 1986 s10 blazer 2wd. The transmission will go into drive but it won't shift thru the gears automatically. Manually I can shift thru 1,2 and 3 as well as reverse. But it won't automatically shift and slips above 2000 revs when in drive. I've taken it to a transmission shop and they said the transmission itself was all clear and that I have a wiring problem. When using an older snap on code reader on the obd2 I can see the VSS and TPS reading clearly. I can also see the solenoids clicking on and off. Any ideas on how to fix this would be much appreciated.

 

If you are seeing the solenoids actuating the wiring and electronics should be good, right?

 

You didn't say how many miles are on this used transmission. If you haven't yet, you should install a gauge and check line pressure.

 

Did you also install the pcm and wiring from the 2000 to the 1986? don't see how anything would work electronically unless you did.