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What leads up to and causes transmission failure? I blew the motor in the truck and spent almost three months of downtime getting it figured out. When I got the truck back everything semed fine until it wasn’t.
Transmission temp sky rocketed to 220 and just kept climbing where it peaked at 250 (probably more in reality) started slamming into gears, up and down shifting, and tow/haul mode flashing. All within 1/4 mile on a residential street.
Before the engine replacement I had just towed 5,000 miles from Houston to Seattle and back with no issues. I had the 6.4 pan and bypass filter, just did a drain/fill last year, and no problems until a cannibalism 2 hours after getting my truck back.
Without tearing down and inspecting the transmission it's impossible to say why it failed.
Mark in a case like this and even others what would be the best way to start to track down the cause? I am guessing but I would think
a person would want to verify if the torque converter was mated to the block if the block was removed or can you tell once it out of the truck
id it was not mated correctly?
The only way I could diagnose what failed is by taking it out and tearing it down. If the converter wasn't seated properly in the pump it would be very evident. I don't know what you mean about the converter being mated to the block - it doesn't mate to the block, it mates to the pump and to the flex plate.
I think what he was asking Mark is about damage that can happen during the re-installation of a motor in a truck. LCR had just replaced the motor and then had the trans failure. In the past there have been a few others who seem to have the issue, so I think Sean is asking if moving the torque converter back to far or some other improper moving/Installation of the converter when reconnecting to the flex plate could be the issue.
I agree with Jack, new mill, converter not turned in the right way. Bad juju. It happens to the best of them. I'd be at the shops door on this one big time. I'll bet the pump is done. There's your sign.
So it’s back at the shop, rebuilt OEM installed is quoted at $4,500. How do I go about having the shop verify the engine was mounted correctly to the flex plate? I’m not saying it’s impossible to have the trans blow itself up at any time but to have it happen 2 hours after getting the truck back from a new engine install I want to make sure everything gets checked out?
I’m not that familiar with the problem, but I think what I’ve read in the past it’s not a flex plate issue, but how the TC is mated to the pump as Mark said above.
So it’s back at the shop, rebuilt OEM installed is quoted at $4,500. How do I go about having the shop verify the engine was mounted correctly to the flex plate?
It's pretty much impossible to mount the flex plate incorrectly to the engine. But if someone achieved that it wouldn't cause a transmission failure.
If the torque converter wasn't seated correctly in the pump that would cause a transmission failure. When the old engine was removed it's very easy for the torque converter to slide forward and disengage from the pump. If that happens and the torque converter isn't seated correctly when the new engine is installed it will cause this type of failure.
When the trans is torn down an experienced trans person can easily determine if this was the case.
It's pretty much impossible to mount the flex plate incorrectly to the engine. But if someone achieved that it wouldn't cause a transmission failure.
If the torque converter wasn't seated correctly in the pump that would cause a transmission failure. When the old engine was removed it's very easy for the torque converter to slide forward and disengage from the pump. If that happens and the torque converter isn't seated correctly when the new engine is installed it will cause this type of failure.
When the trans is torn down an experienced trans person can easily determine if this was the case.
Thank you, I'll bring that up to the shop and ask for the inspection. The OE engine was removed 70K/3 years ago to do the studs so I doubt it was installed incorrectly then and that's the only time the engine/trans have been messed with before.
So is it safe to say that if the pump and converter weren't seated properly when it's torn down then the only way for that to happen was during this recent engine removal?
It's pretty much impossible to mount the flex plate incorrectly to the engine. But if someone achieved that it wouldn't cause a transmission failure.
If the torque converter wasn't seated correctly in the pump that would cause a transmission failure. When the old engine was removed it's very easy for the torque converter to slide forward and disengage from the pump. If that happens and the torque converter isn't seated correctly when the new engine is installed it will cause this type of failure.
When the trans is torn down an experienced trans person can easily determine if this was the case.
Sorry about the half asleep post. That post was a bit jumbled. Between you and jack you got what I was thinking.
To the OP if the shop is good and stands behind there work then I would let them do the work. How ever if there is any
question about it I would have someone else do the dissassembly and investigation.
My last trans came from Ford by way of Ficmrepair. The price was right and the fact it was from Ford helped a lot. I did return
a known bad core I got for $230 so I could take mine apart. What I found was the Coast Clutch sun gear had broken loose of
the shell. The disassembly is not that hard it the experience of the mechanic doing the work that will help get to the root cause
of the failure of this trans.
BTW the new trans was shipped with fluid and the torque converter installed and strapped into place. The only thing you have to do is
flush the lines and oil to coolant cooler. They send a new oil to air cooler because it's not effective to try to flush it. Too many small passages.
What is the best way to insure the converter is seated correctly when re-installing a motor after removal?
The front face of the torque converter needs to be inside the bellhousing. If it isn't fully seated the converter will stick out of the bellhousing.
Originally Posted by LCR
So is it safe to say that if the pump and converter weren't seated properly when it's torn down then the only way for that to happen was during this recent engine removal?
Yes, it's safe to say that. If the converter isn't seated properly it will last a few miles at the most. It won't last a hundred miles.
07-21-2018, 04:47 PM
