2019 28K miles AE80F issues no forward gears - reverse works but we aren't driving home in reverse (1 Viewer)

[deltapine1]

2019 with almost 29k on it. Spring Break and all forward gears crapped. No warning lights on the dash. Reverse works fine and the engine runs fine. It will pull slightly when in drive on completely flat ground but not enough to drive it anywhere. We had a oncoming vehicle kick up some gravel at a crossroads and chip the windshield and the grill badge has a large fish eye in it. Would the front radar/lidar prevent the vehicle from driving forward due to thecrack in the grill badge?

 

[kcjaz]

I don’t think broke radar would disable the transmission. At least not the radar cruise part. I drove a year with radar cruise disabled. Maybe there is something in the pre collision system that could do that but I wouldn’t think so, especially at a low speed.

Did it happen as soon as you hit the gravel?

 

[linuxgod]

I’m not a pro mechanic and I’d suggest using a code reader, but given your symptom this seems like a fail safe where the power to the transmission control module has failed. Maybe the gravel kicked up somehow knocked the wiring loose?

 

[TeCKis300]

Is there any leak under the car? Could be as simple as low fluid. Either from a small leak or due to the incident you described. There is a transmission cooler ahead of the radiator that could be vulnerable (boxed in red), and the circuit does also tie into the bottom of the main radiator.

Unfortunately there is no transmission dipstick and it requires checking fluid level through a process that brings the transmission to operating temp and fill hole on the transmission itself.

 

[MtnAddict]

ABS sensors? Check all four wheels.

 

[deltapine1]

Is there any leak under the car? Could be as simple as low fluid. Either from a small leak or due to the incident you described. There is a transmission cooler ahead of the radiator that could be vulnerable (boxed in red), and the circuit does also tie into the bottom of the main radiator.

Unfortunately there is no transmission dipstick and it requires checking fluid level through a process that brings the transmission to operating temp and fill hole on the transmission itself.

View attachment 3276965

Good call. After more examination the grill took a large (3") rock and the grill broke allowing the rock to lodge against the transmission cooler. There is no sign of a leak but I will need to replace the transmission cooler as it looks like the tube are bent slightly.

 

[deltapine1]

I’m not a pro mechanic and I’d suggest using a code reader, but given your symptom this seems like a fail safe where the power to the transmission control module has failed. Maybe the gravel kicked up somehow knocked the wiring loose?

View attachment 3276944

It very well could be in 7th or 8th gear. The gear indicator on the dash shows D, s1, s2, s3, s4, s5, s6, s7 etc. I don't know if the transmission would be 7th or 8th gear and the indicator show something different.

Reading above that says if the TCM senses a shift solenoid failure or malfunction it performs a failsafe mode. Does anyone know what performing a failsafe mode means?

 

[linuxgod]

I think limiting to only 7th/8th gear *is* the failsafe. It's a failsafe for when the TCM power supply voltage is low (or missing?)

If you go into "S" mode and force the truck into 1st gear, I assume the behavior is the same?

One of the FSM troubleshooting pages says to try disconnecting the transmission wire connector, and then driving to see if the transmission only has Park, Reverse, and 3rd. There's also a mechanical test which involves you essentially power braking and then watching the engine RPMS to see at what speed the engine stalls... if the stall speed is higher is means you have a slipping clutch or low fluid/low fluid pressure. (And given you said the radiator took a rock, I would be concerned there could be a fluid leak, so I'd definitely suggest checking the fluid level as described above)

I'd really recommend getting a good code reader on the OBD2 port. If you have a bluetooth OBD dongle you can use OBD Fusion (you might need to spring for the extra $10 Toyota enhanced PID pack). There are likely codes stored which don't set off the check engine light but which would help you troubleshoot. The FSM has tons of troubleshooting but nothing that directly matches your issue

 

[deltapine1]

Well my stall speed is much higher than the 2350 rpm and there is no way to measure the shock felt when placed into Drive. There is not a shock felt.

Toyota Dealer thinks the "Forward Drum" is gone. No codes or DTCs for the Transmission or Engine. The guy said if the clutches or drum is gone it won't throw codes and he has seen several of them so just plan on putting a transmission in it.

I don't think I am going to accept the 8 speed is a bad transmission and they just crap with 28k on them.

 

[cruiseroutfit]

Wild!

 

[grinchy]

Is it under warranty?

 

[linuxgod]

Seems highly unlikely to me to have gone out unless you leaked out a bunch of trans fluid.

Dealers are notorious for saying “transmission is shot, replace it” but it turns out it’s something else. I’m aware of several cases on the forum, at least one or two was a bad valve body. If they’re planning to charge you for the transmission and it’s not under warranty I’d absolutely look for another opinion. Also if you’re out of the 3 year warranty I’d contact Toyota corporate and your regional Toyota as well and lose my sh*t with both over this

 

[deltapine1]

No warranty. Anyone have a reputable shop that has experience building an AISIN? It sounds like parts availability could be an issue.

 

[brasskey]

Pardon my ignorance, but shouldn't this be under warranty if it's a transmission? The standard powertrain warranty is 5 years, 60K miles.

 

[HUZZAH]

Any update on this unfortunate issue?

 

[deltapine1]

Warranty replacement of transmission and transfer case shift actuator complete and it is driving!

 

[Sandroad]

Warranty replacement of transmission and transfer case shift actuator complete and it is driving!

Any further info on the failure mode?