Serious advice needed. Complete Transmission Failure

Hey, TacomaWorld community,


I’m dealing with a pretty serious issue on my 2019 Tacoma TRD Off-Road, and I could really use some insight from anyone familiar with transmission systems or Toyota’s warning lights.


After some body shop repairs, I was back on the road when my transmission suddenly failed with zero warning lights to alert me. The failure was due to the transmission cooling line not being reattached properly, causing an active transmission failure while I was driving at highway speeds. No master warning lights, no indication on the dash—nothing to alert me to the fact that the transmission was actively failing until it was too late.


My questions are:

Is this normal? Shouldn’t there be a warning light or some alert if the transmission cooling line isn’t connected or if the transmission is actively overheating/failing?

 

There's no way for it to know there is a fluid leak, the first symptom would be slippage due to lack of fluid pressure but at that point most of the time it's too late.

It should be on whatever shop that did the repair and left the clamp loose to make it right.

 

Agreed. Body shop messed up and now owes you a new transmission.

 

No, there would only be a warning if the fluid was over temp, if there's no fluid in it to heat up it won't be over temp for the sensor to register. At the point that its lost fluid below the pick up in the pan its going to instantly cook everything, torque converter, etc.

I'd also be in contact with insurance (if the repairs were through them) and have them help sort it out stating repairs were not completed before vehicle was returned.

 

Welcome to the forum. I’d take the report to the shop that did the repair work and tell them that they owe you a new tranny.

 

We need a lot more info......
What type of accident did you have? What damage was repaired to the truck? What parts were replaced?
Why does your estimate say that another "Other Dealership" did the work? Why not bring it back to that "OtherDealership"?

 

If I understand your description correctly, you had a rapid loss of automatic transmission fluid.

I know there is a transmission temperature sensor, but it’s not clear if it would have sensed anything out of the normal.

I don’t know if there is a fluid level or fluid pressure sensor. Based on your experience, it sounds like there isn’t one. That’s not surprising, because it should be very rare to rapidly loose all your transmission fluid.

I’m skeptical that this fluid loss destroyed your transmission. Mechanical parts don’t fail instantly because of lack of lubrication, albeit it’s not good for them. Did the tech refill the transmission and then test it?

Suggestion: collect more information.

 

Read the invoice...

 

I read it. Did I miss the part about the tech refilling the transmission?

Opps I did.

Someone educate me. Why would an automatic transmission fail so fast due to lack of fluid? Is it the clutches? Steel gears, bearings, etc. don’t fail instantly due to lack of lubrication.

I suppose my assumption that it failed fast could be incorrect. It’s unclear how long it was driven with low fluid. However, I would expect the transmission to act very oddly with little to no fluid.

OP, you noticed nothing at all until what? Give us the timeline of what you experienced.

 

It doesn’t matter. The body shop should have insurance for this type of stuff, and even if not . It’s on them period , and I would demand it repaired at a Toyota dealer .

 

Assuming you are replying to me, I will point out that the OP asked these questions:

Is this normal? Shouldn’t there be a warning light or some alert if the transmission cooling line isn’t connected or if the transmission is actively overheating/failing?

 

I guess I didn’t come off clear . But usually once the fluid get to a point of being low the tranny will slip under load. Now I will say if it’s in one of the overdrive gears on the highway it I’ll go un noticed for longer . But still no matter what it will eventually start to slip. At that point if you were to stop driving I think the trans will usually be ok . But it’s hard to say . Most shops stay away from transmissions like the plague . The whole situation is lousy . But in the end the shop that did the repairs is on the hook

 

transmission uses the fluid in multiple ways, in addition to providing lubrication and cooling it provides hydraulic pressure to apply and decouple internal components, the convertor requires fluid to engage the pump, once the pump stops spinning things start to go really bad really quickly.

 

I’m aware there are hydraulics involved, but that doesn’t fully explain the failure mode to me. Which parts fail?

 

the clutches sort of weld themselves together, the seals start to tear, etc. there wouldn't be any kind of warning system for this level of failure, its not common enough for sudden complete loss of fluid to warrant the engineering time spent on something like that.

 

Hydraulic pressure drives the transmission and keeps the clutch packs tight.

The external lines on the transmission go to the radiator.

The simplest of explanations is,

The transmission pump picks up fluid from the pan. It then send the fluid through the transmission and out to the radiator to be cooled. The fluid never made it back to the pan because it was leaking at the eternal lines to/from the transmission. Since fluid never made it back to the pan, the converter and clutch packs went dry and lost pressure. The fluid never got hot. There was no fluid to get hot. It had all been pumped out of the leaking line.

 

Not only that, cooler return flow is often used to lubricate the planetary gearsets in the rear of the transmission. Without the return oil flow the gears will quickly overheat and be damaged.

It's not often that an automatic transmission that is driven with a fluid leak to the point that it quits moving is salvageable without a full rebuild, occasionally they will be ok but not very often.

 

It seems odd that there were no signs or symptoms whatsoever until the vehicle simply stopped moving. It should have had some rough shifts at least....

 

How long after the body shop repairs did the tranny died? Same day, next day, a week??

 

To me this doesn't seem like all of the fluid leaked out at once. It's probably been leaking since the start and there should have been signs that were likely ignored. The truck has been driven on low fluid for a while and it finally got low enough to no longer maintain pressure and cooked the trans.

Unless OP is saying it all leaked out at once which I don't see how, even at highway speeds, you wouldn't notice that. It would make a James Bond level smoke screen and smell that I don't see how you'd miss.