Transmission replacement problem

my trusted 03 toyota landcruiser has shifting problem right after the engine got overheated, due to radiator fluid leaked. due to its high mileage (450k), we decided to replace it with another used lower mileage trans. however, the car has the same shifting problem immediately after the new trans was put in. we suspected the repair shop didn’t flush out the old trans fluid in the system, and didn’t replace the fluid in the new used trans with new trans fluid, which is suspected in causing the shifting problem, via solenoid code a,b, and e, our dilemma is whether to claim warranty on the trans (6 months warranty by lkq) and incur another install labor cost, or make the now trans on the car work by having the repair place flushing out the trans fluid that might have caused the solenoid code to come up in the first place. please help, whoever might have similar problem with transmission issue like our . tks

No offense, but I’m still trying to wrap my head around why you’d replace the transmission on a 15 year old with an overheated engine, with very high mileage to boot?

Be that as it may…given the circumstances there’s no telling what the issue is. If it’s a rebuilt transmission, I’d wager it was filled with new fluid from the rebuild place. Having a little of the old fluid in the cooling lines wouldn’t cause any trouble.

Good luck.

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Since it is a used transmission a fluid change, changing the screen/filter if so equipped, and pumping new fluid through the transmission cooler MIGHT help. You need to weigh this cost vs labor cost of a second replacement.

In for a dime, in for a dollar. You have now discovered the risks of putting in a used transmission or engine. If it doesn’t work, you are still on the hook for a substantial cost. If it still does the same thing as the other transmission, either it’s a general problem with these transmissions, or it is something that was not replaced, like electronics. I really doubt a fluid change is going to do anything, and before doing any more work and new solenoids, I would have a real transmission shop or the dealer, do a diagnosis on it.

Then I agree, maybe it was time to simply let this vehicle go with a suspect engine, and now transmission issues. How many more miles do you expect to get out of it?

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450k/15yr=30k/yr. whew. thats a good amount of driving. i assume quite a few things have been changed. you are saying the new trans shifts the same as the bad one? that cant be a fluke.

Both transmissions throwing the same codes, I’m thinking it might be what ever electronic unit that controls the transmissions shifting could be bad.

Submit the warranty claim and see what happens. Even if you change the fluid, you can still submit the claim. If you change fluid, do it this weekend or early next week so that you still have time for a warranty claim.

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The last LKQ transmission that I installed they had removed the filter to assure that a new filter would be installed, I wouldn’t assume that the fluid and filter have not been replaced.

If that shop does not regularly replace or rebuild transmissions they may not have a machine to flush the transmission coolers, debris in the transmission cooler can cause problems with the replacement transmission.

When these transmissions fail, the solenoid performance fault codes are generally similar with each vehicle so you may have bought a failed transmission.

Good ideas above. Another possibility (less likely, but worth checking) is the original problem was a leak in the transmission cooler allowing coolant to flow into the transmission fluid.

Tks, clarification. I replaced the old trans with 450k mileage with a used lower mileage 162k. It’s a used from low, and not a rebuilt trans.

That’s prudent , tks

maybe you assumed a 162k trans would provide a fair amount of future use? the fact that new trans has same issues as old trans is a bit of knowledge. where you go next is unknown