95 4runner
3VZE 6 cylinder
A340H Auto Trans
4WD
180,000 miles

I recently encountered a shifting problem when cruising and decelerating. During acceleration, it upshifts through the gears fine. When cruising usually, at about 40mph, the transmission seems confused at which gear to be in, either 2nd or 3rd. If I throttle off, it downshifts into 2nd. Throttle back on and it shifts into 3rd. At one point accelerating on to the freeway, it wanted to stay in a lower gear and the rpm's nearly red line. If the OD is off at higher speeds, and I press OD, it engages, but doesn't affect the downshift issue when the throttle is let off. This happens regardless if ECT is selected.
I have replaced the TPS and the 3 shift sensors in the transmission, as well as transmission filter and fluid changed. I have no error codes present nor any warning lights active. It just seems that the transmission is confused and I don't really think its the transmission itself. Any suggestions on where to look next? any help is appreciated.

 

I'm having the same exact problem seems it can't make up its mind any thoughts?
Gotta be somebody out there that has fixed this issue before

 

I had the same problem in a 2000 S-10 I had. It turned out to be arcing spark plug wires. The ECU didn't know what to tell the transmission because of all the funky readings it was getting.

 

While this doesn't sound like your problem, the transmission won't shift into OD when it is cold. So if you have a bad engine temp sensor it can produce THAT symptom.

Have your tried the FSM diagnosis? http://personal.utulsa.edu/~nathan-b...34electron.pdf (this includes the easy-peasy way to check your TPS).

Also: http://www.autoshop101.com/forms/AT11.pdf

Good luck!

 

I have that problem. what sensor do I need to switch?

 

anyone?

 

I believe it's the tps ill let ya know as soon as I fix it

 

alight let us know, but I doubt it is the TPS. I thought it was a transmission selnoid. My tranny will not go into OD untill the truck is warm enough.

 

That's the way the factory settings are not much you can do about it my trans just searches between 3rd and 4th at 45 mph and I'm trying to find out why I just OD off when city driving

 

You can do a quick check to find out if it's the TPS by unplugging it. The ECU will go into 'safe' mode and you can drive just fine with the sensor unplugged. Your engine will run a little rich because of this but you'll be able to eliminate that as the problem.

 

"hunting" is a common issue with Automatics and first gen ODB/control software. not much you can do about it other than perhaps OD off or pick a different speed and dont hover in the "sweetspot" for worst hunting.

 

Interesting you would say that because I have the 95 a340h trans combined with a 98 a340f ecu out of a tacoma, the trans was just rebuilt by Amoco so he wanted to use it...

He made it work but the ecu was still meant for the newer trans..
Seems to work just fine besides being pretty sluggish even with the 3.4

 

anyone know what he is talking about

 

Is he talking about the engine temp sensor??? I'm not really sure.....

 

surprisingly enough, I may have discovered my own problem. looks to be the shift linkage is out of adjustment causing the gear selector to be mostly in D but partly in 2nd (if that makes sense). I realized this by chance, and now I make sure it is securely in D, with no hunting for gears... too bad i didn't catch that before replacing TPS and shift sensors...

 

I replaced a lot of sensors and the last was the tps
I'm surprised how much of a difference it made still hunts a little but that's because the speed sensor which I'm not to worried about
Glad you got yours fixed also