I hope someone somewhere has run across this strange problem.
I have just completed a complete engine swap. I have a 1987 ford crew cab truck that had a 351 in it. I bought a 1997 wrecked that had a 7.3 powerstroke in it and I did a complete swap from the dash forward with all the wiring harness and everything complete. Everything went great except 2 small problems the first one has me totally baffled.
1) If I am cruising along with the converter locked up and put my right turn signal or touch the brake pedal with the truck still under load with my foot on the gas it causes the transmission converter to unload.

To me something is back feeding but I can't seem to locate it. I have checked all my grounds, checked all my wiring,cleaned everything. Has anyone ever run into anything like this.

The 2nd problem is due to the gear difference in the 2 vehicles. The 87 that I put the drive train into has a 3:55 gear and the 97 that everything came out of had a 4:63 so it is causing it to shift into overdrive at like 30 mph. I have been told once I resolve my 1st problem that I can take it to a Ford dealer and they would reprogram the computer to adjust for the gear difference.

If anyone has any suggestions or can give me any ideas it would be greatly appreciated. It has me pulling my hair out.

You can send it here or my e:mail is bberra1@tampabay.rr.com.

Thanks alot

Glen who has had enough!

 

First, mine always unlocks when I step on the brake and I have read others guys making the same comments. Do a search for "Coast Clutch" and see if that sums up your problem. If it does, then somehow power from the turn indicators is feeding back as "brakes applied" to the computer. Since you built it, you'll probably be the only one who'll know where that's occuring.

Congrats on actually doing it, been lots of people asking how but never anyone who's really done it (that I can remember).

 

just wondering if you used the same instrument cluster? Steering column?
a boss of mine bought a mustang (that was striped) from a wrecking yard and I had to replace everything from dash to engine compartment including wireing harness. instrument cluster was the cause for blinkers problems in my situation. The only reason for bring this up is cuz ford likes to use same plugs but changes wire location in plugs from model to model and year from year.
good luck
over and out
gseeders

 

I used everything from the wreck into my truck from the front seat forward. Complete dash, wiring and steering column. I had to being that I was going from a gas engine to the diesel.

 

I agree with alanscott. The computer is reading a BOO switch (brake on brake off switch) which unlocks the torque converter (it is doing what it is supposed to do). I don't know why it does it with the right turn signal.
For your gear ratio problem, can't you get an adapter to convert your speed sensor on your trans to read the right speed (which would also correct your speedo to the correct speed)? A transmission shop or a speedo shop should be able to advise you on that.