Kingman

You'll need a new control unit, but it should plug right in to the harness you already have.

The guide I wrote my reply in has troubleshooting for both. And it's still the same diagnostic. But it is a little contradicting...

Ahaha that thing is gay!

Also, fluid line pressure was not an option for this problem. Apparently that corresponds to plugged coolers, stuck valves, and oil pump failure.

Well, I picked up a transmission rebuild and service manual for these, and the probable cause of your issue is the TPS sensor, revolution sensor/ vehicle speed sensor, full throttle detection switch (kick down switch) or shift solenoid(s) valve A or B.

Luckily, I'm still able to baby mine after the tranny cooler, since it's going on a month now with no issue. According to the other booklet though, the problem was more common to be electrical and sensor related, and nothing to do with anything mechanical. I've read 2 tear down and rebuild service manuals since then on the 3 speed and 4 speed trannys. I'm reading one right now. The one I'm reading right now puts SC88's problem "gear change directly from D1 to D3" as #1 Fluid Level, control linkage, #2 Accumulator 1-2 2-3, #3, control valve assembly, shift solenoid valve A, #4high clutch. "Failure to change from D3 to D2 when changing lever into 2 position as #1 Inhibitor switch, #2 TPS sensor, #3 overrun clutch solenoid valve, #4 shift solenoid valve B, #5 shift solenoid valve A, #6 control valve assembly, #7 control linkage, #8 brake band, #9 overrun clutch

Ouch... Did it start doing that suddenly or progressively?

I'm sorry to say, I think your tranny is self destructing, clutches, solenoid, etc. Definitely check for particles in the screen. Is it shifting from first directly to third? And then to fourth, and then back out of fourth into third? Not shifting into second could be a blocked ball valve, but unlikely. Or, the particle came from a disentegratic clutch. As for not staying in fourth...yeah... You might get lucky and the flush will knock whatever particle is trapping a valve in the valve body out, so you can baby the tranny a bit further. The best way in my opinion to change the fluid is to disconnect the fluid lines and pump them the fluid into a bucket. And then remove the pan and filter and clean it out. Then pour the fluid into the line that doesn't pump fluid out until it starts pumping out the other line. But when I thought, and was told, my tranny was done for, after I installed my aftermarket cooler the probolem went away.

I ran Marvel through mine and all it did was piss it off. Could be your problem...

What the fskc? Mine is at 4000! Yours is an '87 correct? That's what your profile information says, but then I see your sig says '90... If yours is a '90 the nevermind...

Since the original thread starter's is a '95, and if the switch is bad, the tranny won't kick down. Big if, but if. That makes sense because the transmission shifts normally on all other accounts. Though, a response to k9sar's post about further clarifying the issue would be nice.

Search! Sounds like a ground problem, or a short.

Is there a relay, or a sensor for the E/AT switch? A lot of vehicles have a sensor on the gas pedal to where if you floor it, it makes contact and triggers an automatic kickdown.

I have excellent compression, one cylinder is a little lower than the rest but not too much. And no, I've never checked my TB for carbon buildup. I suppose I should, hadn't thought about that.

If you're concerned about sound, dynomat the floor, and sheet metal over it, and rhino line the sheet metal. Liner doesn't do much for sound deadening, at all really. The road noise is not even that loud. People who use trucks with rhino lined floors for wheeling usually don't give a hoot (haha hootus) about the sound on the road. Turn the music up louder.

WHAT ARE YOUR RPMS AT 65? Need to compare to mine.

Even the autos have enough power to slide the rear end out while moving around a corner. I was pissed, and late, this morning and as I was going around a corner in my neighborhood, I stomped on it and it kicked down to 1st from 2nd (kinda rare that happens, really) and lit up the right drive tire for a good 15 feet before I let it shift. I could feel the rear end starting to slide too. Neighbors are probably pissed for waking them up at 7am...lazy asses. Now if only I had my muffler off and did it...muahaha.

That really sounds like an electronic problem. If it's keeping the gear, that usually means there's sufficient fluid pressure to hold it. If there wasn't enough pressure, it would "fall" out of gear, or not shift into a higher gear at all. On mine when my stock tranny cooler plugged up(mechanical fluid pressure problem, not electronic), it would downshift at retarded times, sometimes dangerously raising the RPMs (downshifting from 3rd to 1st, totally forgetting there was even a 2nd gear in there). This is because the fluid pump works from the rotation of the rear wheels, slowing down the rear wheels would cause it to not keep up with the amount of pressure the tranny needed when the tranny cooler wasn't circulating it properly, in effect causing the gear clutches to disengage and fall out of gear. If it's downshifting properly while slowing down (I forgot what the points were) and upshifting normally (again) on acceleration until overdrive, it sounds like the mechanical side of the equation is just fine. Of course, there's always the possibility that the special case arises where the problem doesn't make sense with the logistics.

Me thinks too. My buddy has one and it shows up fine. My monitor at home sends it a mile to the right lol.

Colby - Your signature is gargantuan!

Ahahahahaha

I was referring to the 4 speed automatic.