Ericshere03

Hey All,
I just picked up an 88 4runner with 180k miles and a "blown Tranny"

Everything runs fine and appears to be taken care of, good color and smelling ATF (but overfilled), and a big transmission cooler.

What seems to happen is that the transmission works 100 percent for about 2-4 minuets then bam, the transmission acts as if it is in neutral. Turn the truck off for 10 seconds and a get a few more minuets out of it. While in gear and stopped the tranny will grab gear and bog the motor (like normal) but then after a while i will feel the transmission start to let up and the engine will fluctuate RPM and then back to no engagement till i restart.

I do know when i first get the runner going and hold the brake and gas, i see that the transmission will hold at stall (~2400 RPM), wait a few minuets at idle and engine will freespin agian...

Just a few minuets ago I ran to the local parts store and grabbed some "trans tune" (or seafoam for your transmission) dumped the pan and refilled with the trans tune and fresh dex-merc fluid. Nothing changed...

So, My plan is to drive around the block a few times a day and this weekend dump the pan and change the filter... Hopefully it will either free up and behave durring the week or after the filter change

So, Before i got nuts does it sound like something that is easy to fix, am i already on the right track, should i give up and get a junk yard trans... Think its electrical, the TC, selenoids... I dont know alot about autos, i have been driving sticks all of my life.


Thanks,
Eric Wolf

Dan.3

you can disconnect the trans solenoid harness. you eliminate the electrical. you will only be left with 1st 3rd 4th and no TC lock up. if that shifts fine you have electrical issues. I doubt that is the case.

I have a little theory that the trans clutch packs are pretty strong but the valve bodies are the weak link in the trans. If you are bored you can entertain the idea of just swaping out the valve body. its kind of a pain to do but could be alot easier and or cheaper than swaping an entire 340h. the tcase doesnt make the trans easy to work with when removing.

very good possiblily that the valve body and or tranny is fried. These auto do NOT like to be overfilled. They over heat very fast. One way of keeping the trans in good shape is to be pretty accuate with the fluid level on the dip stick

Ericshere03

Where do find the harness connector for this? I see a few sensors down there, the shifter switch, and a 2 2 unknown connectors, 2x3 connectors one blue and one white, are thoes it???

Ericshere03

Nevermind I just unplugged the TCU. Same thing ... So I know The problem is NOT electrical... For now i will continue to let the truck sit and ill put some laps around my block hope to de-gunk the internals and i will dump and fill this weekend...

Ericshere03

1 question, IF in fact the friction parts are ok and the electronics seem to not be causing this, is it safe to say that by replacing the entire valve body that my transmission will function properly?

Dan.3

Possibly. Do not hold me to that it will work if you swap the valve body. Agian its just a theory I have. I have this theory because a buddy of mine had his 340h go out. When he tore it apart he mentioned the the clutches and gears looked fine. His overheated from being filled to much. He was never concerned with putting it back together since he had a 3.4 swap become readily available to him.

So if its not to much trouble of to get a hold of a valve body and swap it out. It MIGHT work.

Agian dont hold me to anything.

Ericshere03

Here is an Idea:
If i were to swap transmissions, could i use a A340F From behind a 22RE? I know i would get the non hydro T-case. I would keep my 3vz bellhousing and TC and swap it out with the 22RE parts... Would that work?

I ask because, i can get a rebuilt auto and tcase from a 22re for 200 bucks.

Dan.3

It could work. I would recommend comparing the two side by side and looking for differences like what side park/neutral switch is on, TC, and solenoid harness plugs. If all looks well I think you will have a shot. The valve body might be different as well. I have looked a little bit over on pirate and was able to find anyone using that trans for 3.4 swap.

I though about using a 22re 340f as well. Im not sure of the spline count on the 340f. It might be 21 where the later model v6 340f is 23. you might be able to use this to your advantage if it does work out. You could easily adapt it for a dual case.

You will have to do your research though

Ericshere03

WOW.... Despita all of the doubts I had, it turns out the filter was clogged.... BAWHAWHAWHA ... Hell yes!!!

Thanks All for your ideas, i was thinking things were worse than they really are... Gotta love da yoders

Dan.3

Nice!!!! good to know.