halfpint23

Update. Took truck into Rick at Snoho Trans again today, to put it on the scope and see what the computer is getting for signal now. Interestingly he noted that where there s SUPPOSED to be a 12v hot (with key on) at the 8-wire connector on transmission, the wire is only supplying 5v at best. His suggestion is to take my time ane effort to do helaing up work on all of the many wires that DTT hacked into with their blasted t-taps when they wired in the failed controller box. There must be an easy dozen of these things, and a few of them are within two inches of the connectors that plug into the PCM on firewall. It's going to be time consuming niggly work. I am good at that and I won't charge me $150 an hour like Rick's electrical guy.

The plan is to make as sure as possible that all wiring is sound and carrying the voltage is should be - no corrosion, no stranded wires etc. THEN if it's still hinky, bring it back in and put it on the scope to check all inner components one more time.
Since all of this stuff was working fine on the old (ruined) transmission, I'm guessing now that being parked for nearly three years in this stupidly wet climate allowed deterioration and corrosion in the already challenged harness.

Oh, one more point that may or may not be of interest - this particular 96 truck had the OBD-II required in the 96, but it is an early production number, and the wiring HARNESS is the older OBD-I compliant harness - so it's really interesting to run testing on.

halfpint23

and yeah, I am sick and tired of this subject too!

SO far NOTHING has returned overdrive to this truck. We have stuff to haul and work to do (gotta make a living) so she's been working, albeit under 50 MPH and on back roads, packing the heavy materials for us.

In review, I have tried putting the resistor inline of the trans temp wire. Completely went through all the hack job damage up next to the PCM box - a LOT of careful soldering and sealing and shrink tubing.
Confirm that correct 5v is at pin 8 at the trans 8-pin connector.
Last resort, tried the TPS delete kit. NO joy, no difference AT ALL.

TRans will start out in THIRD gear from standstill, so have been manually selecting gears especially when hauling heavy. GREAT function on lockup in the downshift, other than no OD I am pretty dang happy with this transmission.

I am left with what? the OD solenoid being faulty? Would appreciate a bit of brain power feedback before I take my list of done-its into trans shop and put the beady eyeball on them to drop pan and replace some "new" components that don't seem to be working.

sgq700

I got real tired of my 94 giving me a bad time so here i found info and cut the 3 wire plug for od and lock up, put 12 volts to the middle wire and ran the other 2 wires inside the truck to 2 toggle switches,1 wire to each switch and the other lug of each switch goes to a good ground. when the switches are off, no OD or lock up, when on, you operate them manually. when you slow or going to stop, do not forget to turn off lock up! works for me as i don't do much stop and start driving. Good Luck... P.S. I don't miss that darn PCM working the transmission at all!!

halfpint23

on finding replacement PCM for this truck....
I did find the one place in the USA (evidently) that does rebuilds for the public. Sent in PCM and my money - they went through ALL of it, said it was flawless, kept my money and sent it back. sigh.

Given the history of chasing this thing, i was pretty down on it, but got in there one day (following finding an ancient post from Infidel, who I'm not sure is even alive any longer!) and did a careful realignment of the posts on PCM (perfectly straight and clean etc) AND lined/resized the tiny sockets in each of the three plug bodies that the harness had. I used a small bore hypodermic needle (we have horses and I have a hefty sharps container) to close the socket a tad on all of them.

Darn if it didn't work. Perfectly....

Then hubby took it in a couple weeks ago to get the exhaust manifold gaskets replaced and it came back sans OD again.
They musta done something else to it too, as now it's starting out in 2nd and no OD. RATS!!

Great, now it's a TWO speed truck. I am out of patience, and being just four months out of lumbar fusion surgery, not enthused about hanging over a fender or crawling under a dadgum truck.

Robert Rausch

Halfpint, I wish I had more words of wisdom for ya.
But I would ask the shop if they by ANY chance disconnected/reconnected anything electrical in order to do the work they had to do.

And I hope Infidel IS alive and kicking. Anybody know for sure?

halfpint23

Robert Rausch, I sincerely doubt the shop even KNOWS if they did anything.

They got the truck in for brakes initially (hubby was whining about not having brakes, for some reason it made him nervous). They went through all that - one bad seal in rear axle with oil-soaked brakes, crappy master cylinder, etc etc. All that resolved, then he had them put in new PS pump (I am not able to get under there any more) AND do the exhaust manifold gasket set I had bought parts for two years ago!.

So, tons of stuff being gotten into and around, and by the looks of things they pressure washed and/or steam cleaned living heck out of her too - so it's a decent possibility something got whacked off underneath. I do suspect they pulled the big harness off the firewall during the manifold removal - it's not quite the way I had it before and they also had the air cleaner intake boot in wonky.... lots of tracks in the butter to indicate an elephant has been in the fridge.
Like it or not I am destined to once more spend a lot of time with this truck - just hope I can magically heal it up again!

I, too, really really hope that Infidel is OK, just have not seen his soothing omnipresence around in some time.