HELP Non-matching plugs on my A4LDs

[jbweldit]

I just got a Bronco II with a bad tranny (reverse ok, but no drive). It came with a supposedly good spare engine and tranny so the plan was to just swap the tranny and get wheelin'. So I got the old tranny out and swapped the filter and pan gasket and replaced the front seal on the new one since it seems to be a fairly common failure. When I go to put it in it seems that the little two prong plug on my truck doesn't like the three prong plug on the new tranny. So after further examination and some consulting the "rebuild diary" it looks like the old one only has the torque converter solenoid and the new one has two solenoids with wires going to that plug. Any ideas on a possible workaround or adapter for this?

 

[Glacier991]

One workaround is to get the harness from a newer one so it fits your wiring harness, and then just clip off the 3-4 shift solenoid wire inside. I am concerned that you may throw a code... you may need to terminate the 3-4 shift wire with a resistor. Brooklyn Bay is the electronics Guru on here so he might know.

 

[MrShorty]

But won't cutting the 3-4 shift circuit result in a 3 speed transmission?

It seems that I've heard that the easiest solution to this is to simply swap the valve bodies. Others have said that an '85-'87 valve body (with one solenoid) will fit just fine in an '88+ A4LD. Anyone confirm?

 

[Glacier991]

If he uses the old VB, the 3-4 shift is hydraulic

 

[BrooklynBay]

Welcome to this forum! The correct solution is to use an 87 valve body in the other transmission, and swap the 3 pin case connector for a 2 pin case connector. The vehicle's computer only has an output for the TCC solenoid. What year transmission was the replacement transmission? Was the replacement transmission originally designed for a 4 X 2 or 4 X 4, 3.0L or a 4.0L vehicle?

 

[jbweldit]

Thanks a lot. I'll swap the valve body and the plug. I'm pretty sure the replacement is from an '88 4x4 Bronco II and it was bolted to a fuel injected 2.9.

 

[Maniak]

If the computer thows a code for the solenoid, just put a 33 ohm resister there. With the resister in place it will think the solenoid is still there (I'm using a 5 watt resister now as teh 1/8th watt one I had in there burned)

~Mark

 

[BrooklynBay]

I never saw a 1/8 watt resistor. They usually come in 1/4 or 1/2 watt, sometimes even 1 watt. They are carbon film or carbon composition. The power resistors are enclosed in ceramic, and are rectangular. Power resistors have Nichrome wire (nickel chromium) inside. The lower wattage resistors are barrel shaped with color coded bands. The TCC, and 3-4 shift solenoids should range from 25 - 40 ohms. On a side note, the case connector for the solenoids has a built in diode.