Transmission Problems (1 Viewer)

[Offroader93]

So, here's the rub, even if you select "L" (1st gear), the transmission is designed to shift into 2nd gear. If you select "2" (2nd gear) or "D" (3rd gear), the transmission starts in 1st gear, then shifts to 2nd, and then to 3rd (in "D", you also get O/D).
This excerpt is from the repair manual (RM479U), showing the normal operation:
View attachment 3454505
When you say "Low was normal", does that mean the engine rpms seemed to match what you expected, AND the transmission shifted from 1st to 2nd, or just that you were able to get it rolling, and it didn't shift?

I apologize for being picky, but these problems are really hard to diagnose without specific faults. FWIW, this is why few people want to work on automatic transmissions. If a carb is wonky, you can watch it and sort of guess what's wrong. The transmission is a true black box.

From what you've shared so far, I'd look at the solenoid driven spools (the sliding shafts in the valve body the solenoids actually move) and the accumulator pistons, particularly the timing solenoid spool and accumulator. This is the "Shift solenoid valve SL circuit" fault from the problem solution matrix (pages AT-61 to AT-63).

Unfortunately, this requires removal of the cover to get to the spools and removal of the valve body to get at the pistons. If you have a spare gearbox, it might be helpful to take a look at these on that unit, before trying to get at them with the case bolted in the truck. The unit repair manual (RM479U) is the manual you need for information on all these parts (they are illustrated in the Repair Manual [RM432U], AT section, but not identified there).

Before you go to those extremes, however, it might be beneficial to perform the Mechanical and Hydraulic System Tests, described on pages AT-52 through AT-58; this assumes you still have no DTCs. If you do, definitely start there.

FWIW, if the transfer is in H (high gear range) and you can get the transmission to function differently just by moving the gear select lever, your problem isn't drive flanges. At least, if it is, it's a drive flange failure I haven't heard of (which is certainly possible); the drive flange observations above assume that when you describe "Low", you're indicating low range with respect to the transfer case, not 1st gear on the transmission select lever. The two operations are not connected.

Yes, in low on the gear selector (not transfer case), i was able to get it rolling with much less effort (noted RPM seemed normal). I couldn't drive far to see if it would shift, as she's uninsured and not registered at the moment, so i stuck with a few short ups and downs in front of the house. I wonder if I swapped valve body from the other transmission, that the trans would work as should. However this is on the line of time that I don't have. I'm going to get my mechanics opinion on it as well.

 

[jonheld]

I had my doubts when I first read the operation description, but I tried it with my '95 A343F and it operates as the manual says it should. I haven't tried my '94 A442F.

I can only go by what I see personally, and what Toyota published. I'm all for new information, but there's not much published that I could find.

So you're saying that with the transmission shifter in L, your transmission upshifts?? If that's the case, then what is the purpose of L?

 

[Marco Lau]

Did you check the tranny fluid level? Not enough fluid in the tranny would have the same experience in my A440F.

 

[Malleus]

So you're saying that with the transmission shifter in L, your transmission upshifts?? If that's the case, then what is the purpose of L?

I can't begin to guess why the transmission is programmed the way it is. When I was an axle engineer, my next door neighbor (in the office) was the transmission engineer. He was constantly reprogramming transmissions that were supposedly finished, to suit customer requirements - and we didn't build custom transmissions.

 

[Malleus]

@Offroader93 @93z
Did either of you have any luck with your transmissions?

 

[Offroader93]

@Offroader93 @93z
Did either of you have any luck with your transmissions?

I don't have the time or patience to dig into it further, so I am taking it to my mechanic. It needed work in other areas as well, so they'll look into the transmission along with fixing some other things I need done. Thanks for providing your help though, I appreciate it!

 

[Malleus]

Please let us know what they find. There's no such thing as too much information.

 

[93z]

My issue was the kickdown cable was too tight. I still have a flare (what I'm calling it) where the RPMs jump right after it goes in second. It goes 1st, 2nd, revs up for a sec, 2nd, 3rd, 4th. Still trying to figure that out.