91 2wd NO FORWARD

[Homebrew]

First post here. Looking for some helpful answers. Bought a 2wd ext cab 4.o with this problem. The transmission was built 12k ago and worked great. When this problem come to surface previous owner wanted to sell. Anyway just could not pass. Has a new Jasper engine with new everything. Is really crazy. As stated the trans was redone 12k ago and just stopped working. First reverse works perfect... but no forward movement. I disconnect the vacuum line to the modulator valve and put vacuum to it (18-20psi) and with the truck started in gear at idle with in a few seconds it started to pull. Now with a manual in hand said to check fluid. good. step 2 manual linkage will do this next. explained 8lbs weight on shifter. Is this necessary? Then the real question Control pressure test. What size gauge is needed? Do you hook it up at the transmission output line? I only ask because I need help. Also preforming air test? Can some one explain or give guidance. I have started the search and am more confused then when I first started. I also seen the valve body bolts may be to tight but could not fine torque for this in the manual. Thank you for your help in advance.

 

[adsm08]

The 8 lb weight on the shifter is to keep it in place. A wife/girl friend/child/well trained dog holding the shifter in place works equally well.

Control pressure test: I'm not sure of the gauge off hand. Trans line pressure tester is the best thing to use. I believe there is a pressure test port on the opposite side of the case from the cooler lines. Its blocked off by a bolt.

Air test is not really appropriate here. It requires a test plate that, if you had, I doubt you'd need to ask these questions. It's also more to test a rebuild trans than to diag a failed one.

Also not sure of valve boy bolt torque specs. I have never heard of them being too tight and causing a problem (unless the head snapped). Too loose can cause issues. I doubt that is your problem though. The Bordeaux transmissions just seem to have problems with losing forward gears. Roughly half the problems we see are no reverse, the other half are no forward.

As for fixing it. Manual transmission will fix all the problems with your auto.

 

[Homebrew]

Questions???

Ok, with your suggestion to change to a 5 speed. Need information on what years will fit. Is there a place where this is listed. Someone mentioned up to 1997 v6 would work is this true. Just new to this and with help willing to get dirty. Thanks again.

 

[adsm08]

That is partially true. You want to be sure to get the M5OD, so stay away from 80's transmissions. Your engine will tear those apart.

You want to find one from either a 2.9L or a 4.0L. The 3.0 uses a different bolt pattern and the bell isn't changeable. You would also need a pedal assembly, starter, flywheel, all the hydraulics, and probably want to find a computer.