2001 4Runner Transmission issue

[sixsrepair]

Hi guys, I am having an issue with this truck not engaging transmission in drive. Customer brought this to me in this condition, fluid was the consistency and color of chocolate milk. Low works, 2nd gear and Drive do not until you attain 10MPH exactly, then Drive engages and truck shifts normally. One DTC is set "P0770", in my research I cannot confirm this code should be causing this issue. Here is what I have done:
Drain and refill 3 times, fluid is now normal color.
Filter has been changed.
Trans. solenoid SL has been replaced with factory part.
ECM swapped with known good.
All wires pertaining to transmission control have been traced and continuity verified. Solenoids, speed sensor, TPS etc.....
Speed sensor replaced.
Manual shift test per FSM performed and passed.
Valve body removed, split and thoroughly cleaned, all valves move freely.
I am nearly at my wits end with this one. Long since stopped recording the hours I have put into it. I just want to give this guy a working truck back. Any and all help would be appreciated, somebody else must have run across this issue in the past.
Thanks, Steve.

 

[skaterdemon69]

Have you tried the actual transmission module? It's in the driver's side kick panel usually. Don't know if it will help but worth s shot

 

[sixsrepair]

Was not aware there was a TCM for this application. None of the info. I have from FSM or AllData show a separate TCM for this vehicle. I was under the impression that the ECM controlled this tranny. I will check.

Thanks, Steve

 

[SteveH]

Sounds like you're doing all the right stuff. Did you figure out how the tranny fluid became the color/opacity it was? Age/abuse and/or water contamination?

If you have a coolant leak through the trans cooler, you should address this, too.

 

[sixsrepair]

I have not. Customer bought this truck recently as an investment and planned to turn it over for a profit. Oops. My theory is that somebody added an unidentified contaminant to the transmission. Coolant system holds pressure. The fresh transmission fluid is showing no signs of "milkyness". Don't know if it was some sort of friction modifier or a case of somebody getting back at somebody else.

 

[vogs77]

I dont believe there is a separate trans ecu on these 4runners, everything is controlled through the main ecu. As far as the fluid color, does the radiator look new. They are know to blow trans coolers and cross contimanate the fluids. If it is a new rad the damage may already have been done and the trans will need rebuilt or replaced with a new Toyota reman. This was the case on the last 4runner I owned, fourtunately I bought it just after the previous owner replaced both trans and rad with Toyoto parts.

 

[sixsrepair]

Fluid has been changed 3 times now, it is staying clean. Pressure tested cooling system and holds pressure. Performed manual test with transmission disconnected from ECM and vehicle passed per FSM. I don't believe I have a mechanical failure due to these findings. I am convinced it is electrical in nature. Either an ECM input, broken wire or bad sensor. Have tested everything I can think of and have performed the FSM pinout tests for the transmission. I am stumped.

Thanks for the heads up on the fluid exchange, that's the first thing I thought of when I saw the color and consistency of it.

Steve

 

[Mr Chuck Norris]

All I can think of now is to swap ECMs and see what that does.

 

[sixsrepair]

Did that as well. Never have I seen a Toyota ECM gone bad but I convinced myself that was the case. Bought a good used one and gained power to a second gear shift that wasn't there previously. Still no drive. Frustrating.

Thanks for the input.

Steve

 

[liljlandon]

I dont believe there is a separate trans ecu on these 4runners, everything is controlled through the main ecu. As far as the fluid color, does the radiator look new. They are know to blow trans coolers and cross contimanate the fluids. If it is a new rad the damage may already have been done and the trans will need rebuilt or replaced with a new Toyota reman. This was the case on the last 4runner I owned, fourtunately I bought it just after the previous owner replaced both trans and rad with Toyoto parts.

Pull the passenger kick panel, the 02 I was going to strip had one.