Quote:
Originally Posted by herkyhawki
Thanks , but I'm just trying to make a fact-based diagnosis of the problem.
From what I've read, P1870 is set when the PCM senses slippage between crankshaft and driveshaft. Your advice would make sense only if this if is incorrect, so please correct me if needed.
Does P1870 sense crankshaft-to-driveshaft or does it sense transmission-input-shaft to driveshaft??
When slippage is detected, the PCM raises the pressure to try to limit the slippage.
My question is if a high-end scanner is able to provide enough information to determine if the slippage is in the torque converter or if the slippage is in the transmission itself.
A typical trans rebuild includes a new Torque converter, so the question is usually not answered (was the trans slipping? or was the torque converter clutch slipping?)
The total rebuild solution does not find the source of the problem, and the conventional wisdom of "replace it all" is only to the benefit of the mechanic that was unable to make the diagnosis. Why spend money on parts that have not failed???
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To answer your first question.
Yes a good scanner will pinpoint where the slippage is.
But the root cause of slippage is internal transmission pressure leakage.
There is a lot of band aids like valve body and converter replacement if the converter is where it is slipping.
But it always goes back to internal pressure leakage as the root cause.
And the only long term fix is to fix the internal leakage.
Which will take a transmission rebuild or replacement.
Good Luck