Can't seem to find it with search so if the answer's in here... my bad.
Is there any known fix or a/m shift kit to fix the crappy auto trans? Given the 3.0 has no power but the more I drive her, the more third gear bugs me. I get up to 750 rpm slippage and I think it's the cause for my increasingly crappy mileage. (This is my first 4R winter and I'm down to 11-12 mpg) Hard to believe that's normal but most 4R owners I talk to confirm it. I'd pop a better tranny in there if I had a clue where to start.

 

Might be good to know which A/T is already under there -- A340H , A340F or A340E. Check the driver's side doorjamb sticker for the info. Also -- how many miles on the 4Runner and how long since last fluid change?

I'm curious to know how you are calculating slippage. Are there taller tires on than what came stock and are you calculating your odometer shortfall if there 'are' taller tires?

What is it about 3rd gear that bugs you? Do you feel that is the only gear within which slippage occurs?

The tranny 'may' be somewhat to blame , if you have some problems there. There are several threads on here regarding poor mileage and some suggested remedies. A general rule of thumb is to make sure that the engine is operating properly and as efficiently as possible before trying to diagnose any automatic transmission trouble.

Keep us posted

Mike in AR

 

Sorry... you're right... not enough info.
I bought her used last April (last trans fluid change was then). She's at 110K and has a A340H trans. I've put 6K on her since getting her from Toyota dealer.

By slippage I mean that shifting from 2nd to 3rd there's barely a drop and if you ease off the throttle in third and the rpms settle at say... 2500 you can gun it (actually any acceleration attempt) and get rpm to 3250 without feeling much pull at all. Makes me wish it were manual. I'm losing what little power I have in the TC. (until 4th gear which locks up nicely) The other gears do the same but not as bad. I took it to a tranny guy (no not a guy in drag) and he said that's just how they are.
Sound like yours? Or abnormal?

 

I'm no transmission specialist, but I do have an A340H in my 92. It has 182,000 miles on it. Not sure if it's ever been overhauled, tho. I purchased it with 145,000 miles.

If I were to guess, it sounds like you may have some shift solenoids that are going out. All the shifting in the A340H is controlled by electronic solenoids. There are no brake bands to wear out. That being said, if it's not solenoids, then it's probably seals iniside that are wearing out and reducing pressure in various gears.

The experience with mine has been that -- until the transmission warms up to above about 160 degrees, you effectively have a 3 speed transmission. Fourth wont come in, until then, even though the engine appears to have reached normal operating temperature. The engine temp gauge is not 'super' responsive. Additionally, I have noted that my converter won't lock up, either, until the 160 degree mark is reached.
Low gear in the A340H is 2.80:1, 2nd is 1.53 and 3rd is 1:1. Overdrive is .7:1. So you can see there is not much difference between 2nd and 3rd, ratio-wise. When my 4Runner is completely warm and I accelerate at a reasonable speed, the converter locks up almost immediately after the tranny hits 3rd gear. Your converter lockup solenoid may be getting a bit faulty or a transmission temp switch is faulty.

Hope that helps
Mike in AR

 

Thanks... that's good to hear. I'd rather have a faulty trans than a trans designed to be crappy. Mine behaves like yours pre-warmup. But the 3rd gear lockup never happens even w/ OD off.

 

From what I've read about the 2nd gen automatics, they are built pretty solidly. Sure, every vehicle wears out over time, but mine has almost 183,000 miles on it and 'seems' to work pretty well. At least Toyota saw fit to put an inline oil cooler under there. That, by itself, helps extend longevity. They are made by Aisin ( same company that makes Aisin hubs ). These Aisin trannys are in several different makes of 4-bys: Jeep and Nissan , to name two.

Mike in AR