No torque to wheels

[DougR]

I was not there for this flush to see exactly how it was done, but the spec fluid capacity is 11.3 quarts. 2 quarts is not going to drain the system dry and the fact that it was pumping fluid out is proof of that. Plus, if done right, the pumping is very brief. Again, I was not there, but if done properly, hard to believe that was the cause of your damage.

I agree with you. I don't see how the pump could be damaged by 2-quart exchanges since others have performed it successfully. When I changed the fluid, I was more concerned about losing pump prime. I drained the pan first and added back the same amount plus an extra 1/2-quart of new fluid. Thereafter, I pumped out about 2-quarts and put in exactly the same amount until 3 gallons was consumed and then set the fluid level with a warm transmission.

 

[Jetboy]

That's a bummer. Sorry to hear. Thank you for following up so we can learn from it. It makes sense for the symptoms that the pump failed. No oil to the torque converter would cause it to stop transferring power. I'm assuming it sheared the machine keys on the pump star gear?

For folks who may be curious - this is what an oil pump looks like on most transmissions, this one is an A750E pump according to the video

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If it's not too much detail, I'd love to understand better for my own curiosity where the scarring and seizing happened. I can see two obvious places where there would be close tolerance bushing that could have issues if they ran dry. In my super amazing MS Paint arrows below, there's one bushing surface where the red arrow is that would be where I'd first expect a problem. The second place is a bronze lined bushing with oil pockets that seems like it must be prone to oil starvation based on the design. And the third is the actual pump cavity. That is where I wouldn't expect a problem unless a foreign body was introduced via the oil flow and then got compressed in there and caused damage.

Here's a closer picture of that bronze bushing I'm thinking of that the green arrow is supposed to be pointed to.

One other thought just to keep in the back of your mind - it's possible that the failure was unrelated to the oil swap and something just went bad randomly that out of pure luck happened at about the same time. It's not likely, but not impossible. The reason I say that is it seems like under low rpms and light load the pump should have enough residual film to run dry at least for a short period of time without damage. That I've had an auto transmission in the past that broke a cooler line and pumped out all of the oil completely until it stopped moving. I refilled it and it worked fine. It was a GM TH350 a long time ago. Very different transmission, but it uses the same basic design for the oil plump. So it might have just been shitty luck.

 

[rdruss]

I went back to page 3 and the dealer's analysis, he said no codes at all. How can that be if the trans lost charge pressure? That is one of the few failures that will totally stop this trans as happened in this case, barring mechanical breakage. It appears that all other failures are "fail safe" in that they don't totally disable the trans.
Also, dealer's are foolish, at least this one was for not offering to further diagnose and determine what is really wrong, then make a repair and/or replace if absolutely necessary, like the trans shop is doing. They just want to quick diagnose and then offer the highest $$ alternative possible it seems.

 

[osugsxr]

I went back to page 3 and the dealer's analysis, he said no codes at all. How can that be if the trans lost charge pressure? That is one of the few failures that will totally stop this trans as happened in this case, barring mechanical breakage. It appears that all other failures are "fail safe" in that they don't totally disable the trans.
Also, dealer's are foolish, at least this one was for not offering to further diagnose and determine what is really wrong, then make a repair and/or replace if absolutely necessary, like the trans shop is doing. They just want to quick diagnose and then offer the highest $$ alternative possible it seems.

Understandable for dealer to offer a solution vs digging further into it. How many more labor hours would it require, cost effective for consumer?

Years ago I had a cadillac DTS and the water pump & thermostat went out. A few shops refused to work on it b/c of the amount of labor hours. A few cadillac dealers stated they didn't have the personnel. Searched around and found a shop at a good price and after they were done, the owner stated I should've charged you double, took about 10 plus hours. Believe I paid $1100 for an oil change, power steering line, water pump and thermostat.

 

[magnetic.gry.rnr]

UPDATE: back on the road about $3k later had to replace torque converter, pump, and a few other smaller parts involved with taking down the front of the transmission. I really don’t know how else the pump would’ve ran dry since I followed the steps outlined in many forum posts for a full fluid exchange. Was the repair Worth it? I think so because I was able to see the point of failure and get good recommendations on whether something further back was affected. Shop was top notch, master technicians were top notch. Easily could’ve told me that a full rebuild was the only fix but they actually recommended against it. Im just glad I was able to fix the OG trans and not completely reo it or throw a mystery trans in it and pray that it worked. Thanks to everyone for your insight and help.

 

[Hammer0313]

UPDATE: back on the road about $3k later had to replace torque converter, pump, and a few other smaller parts involved with taking down the front of the transmission. I really don’t know how else the pump would’ve ran dry since I followed the steps outlined in many forum posts for a full fluid exchange. Was the repair Worth it? I think so because I was able to see the point of failure and get good recommendations on whether something further back was affected. Shop was top notch, master technicians were top notch. Easily could’ve told me that a full rebuild was the only fix but they actually recommended against it. Im just glad I was able to fix the OG trans and not completely reo it or throw a mystery trans in it and pray that it worked. Thanks to everyone for your insight and help.

Glad your back on the road! I find it disappointing that the dealership wanted to replace the entire tranny without even dropping it and looking at it. Either way your back arty:

 

[1jzgte]

After taking down front of transmission that shop showed me that my pump gear was sticking likely due to me running the transmission between filling increments of ATF to pump out of return lines. I did this at 2quart increments. He said it is likely that the pump drained the pan too quickly for me to fill during one of those increments and was enough to cause scarring in the pump gears which overtime got deeper and eventually sheared the pump gear off of the torque converter. So luckily no rebuild but will have to replace torque converter and pump along with various seals and o-rings totaling around 3,300 with parts & labor since they serviced my T-case before dropping the whole transmission to rule it out. My clutches looked great and everything else behind the pump so likely no damage to other parts further back in the transmission.

I advise pinning this post if someone knows an admin. Be very careful when draining and filling that you are replacing the exact amount and I would maybe recommend if flushing doing 1 quart at a time so as to be cautious of an issue like this. I am very lucky I went with a reputable shop with Master transmission technicians that are not BSing me about what was wrong and even let me come in to inspect the damaged parts myself. If you are in the Prescott AZ Yavapai county area it is Certified Transmissions on Iron Springs Rd.

Was your vehicle running the entire time as you drained and filled back 2 quarts?

 

[Humble Leader]

the dealer quote though for a new transmission was $3K, maybe a bit more all said and done. so for just a little more than OP paid for the fixes needed, he could have gotten a brand new toyota transmission (assuming it's new and not remanufactured) on a 180k mile vehicle. and probably saved some time with diagnosis and going to another shop etc

at the end of the day the truck is fixed and that's important, but would it not be better to put in a new transmission if the cost was the same? it seems like in this case toyota had it right with the suggestion of a new transmission because diagnosis and repairing can be hit or miss