Automatic Transmission diagnosis

[Ramdough]

My 2002 AT Tacoma has a problem. 172k miles on it.

A month or more ago, I noticed my transmission shifting hard. In one gear, then all gears. Also my shift lever occasionally had extra resistance when moving it. I took it to a mechanic and he said that it looks like my drive shaft center support bearing was out and there was some slop in my spline/bolt flange.

I replaced the center support bearing and re-torqued the but that holds the spline/flange together (I pinged the nut in place and secured with lock tite, it was loose when I took it apart)

The problem was better for a few days, but got worse again.

I had the right level of fluid, but it was maroon, so I did an oil pan drain and fill with 4qts. Not improved a little but not fixed.

I then discovers my tranny mount w as cracked. I replaced that.... Everything ran beautifully.

I did another drain and fill thinking that I would get 4/9ths fresh fluid.

Two weeks later ( yesterday), I thought I heard some road noise that was a little louder than normal (my truck is noisy anyway). The road was in rough shape, so I was trying to find out if spread mad a difference. It sounded like a tire. I sped up a little and as my transmission shifted, the noise went away. When I slowed down, the noise came back. I was almost home and driving about 65-70mph, when the transmission lost all torque. It was as if I was in neutral.

Towed the truck home. All forward (d,2, & 1) and reverse gears do not work (when I manually shift). At idle, the transmission sounds like there is gravel in it or the pump is cavitating.

I have fluid in it at approximately the right level (did not have a rag).

Assume it is not the torque converter or pump because it carried with what gear I was in. I assume it is not the solenoids since reverse and fwd are both broken.

Any thoughts? Thanks.

 

[zolo]

It is always risky changing fluid on high mileage AT trans. I have seen more than a few trans failures at high mileage due to fluid changes like that. If the trans has not seen regular fluid changes say every 30K and then at 150-172-200K you decide to change the fluid it will most likely fail.
The old fluid wears in and when you swap it out like that it cause the trans to basically not hold any pressure any longer and simply fail.
Sounds like you need a new trans my friend. Nothing else you can to with an Automagic when it loses drive. Its all internal, has to come apart and rebuild or replaced.

I've seen this many times on Toyota's Land Rovers Nissan's. Its a fact of the auto trans and the service history it may not have ever had.

In this article I go over it a little. Basically its highly risky to do what you just did. Unfortunate but true.
http://www.centraloverland.com/2013/09/five-maintenance-tasks-prior-next-adventure/

 

[Ramdough]

Yeah I was assuming that may be the case.

The other symptom is that there were no dash lights that can on. No low pressure or high temp alarms.

 

[pwr2lbs]

Just out of curiosity, Did you check the condition of the flexplate? I have seen them completely break before. Causes all kinds of noise, and the vehicle will not move.

 

[Ramdough]

Just out of curiosity, Did you check the condition of the flexplate? I have seen them completely break before. Causes all kinds of noise, and the vehicle will not move.

No, I have not opened it up. The noise was only there in OD, until it crapped out. Now it makes the noise continuously.

 

[zolo]

If the flex plate broke it would of made a noise similar to a giant metal rotating bomb. If there was such a thing.
It would have been a catastrophic failure. That is not to say it couldn't be cracked but even a cracked flex plate would still have drive.
I've seen it before under load they make noise but still drive. I doubt your flex plate has any issue at all.

Sounds like you have an internal trans issue. My advice for what its worth from a guy you don't know on the internet.
Find the best and most affordable rebuilt trans with the best and longest warranty for your truck. Even LKQ a used auto parts source has warranty on used trans.
Make sure to check references for the builder. The auto trans world is very very hit and miss for quality re-builders.

 

[Ramdough]

So, I can get a Toyota rebuild (from Japan) for the same price I have seen everywhere else with a warranty included. I think I am going to go that route. I figure that Toyota probably can rebuild to the original specs better than anyone else.

 

[Ramdough]

I was thinking that once I get the new transmission, I would put a cooler in and maybe a remote filter. I know some if the diesel guys use them. I can choose between a 15 and 25 psi bypass valve, so if the filter element clogs, it will bypass the add on filter. What do you think? What pressure would you select?

 

[zolo]

If I'm not mistaken your truck has the trans lines that run to the stock radiator which should have a trans oil cooler built in to the radiator?

My advice would be to skip the remote filter and simply add an external cooler in line to the trans radiator OEM cooler. Think of it this way.
You can help the engine and radiator by cooling the oil just enough before the radiator and then cool it again in the radiator and have it return to your trans.

I have an external cooler on my diesel. One for the trans oil and one for the engine oil. They are good to have. I honestly doubt your failure has to do with the filter failing more to do with the fluid simply never having been changed then swapped out twice in a week. I wouldn't over think it to much. Add an external cooler if you want. Its a good idea but skip the extra filter and bypass valve. The simpler the better. If you get a new trans and change the fluid every 30K You will never have an issue out of the trans again.

Keep it simple and don't get to technical about the swap. Remember the stock set up lasted almost 200K. That should stand for a lot.