Check your tach sensor. My truck just started doing this again and I knew it wasn't my wiring cause I just redid it so I started looking under the hood. The insulation on my tach sensor (original most likey) had rubbed off and the wires must have been touching each other with the vibration from the engine. I think when they touch it makes the computer think your at WOT and kicks the tranny out of overdrive. I'm going to pick up a new sensor at the dealer tomorrow.
Question on E40D torque converter is locking, and unlocking
- Thread starter DragRag
- Start date
DragRag
Registered User
I have thought of this also, as a last resort I will do this. Thanks
Shadetreemechanic
Full Access Member
This happened to me as well. Exact same symptoms you are describing.
LCAM-01XA
Full Access Member
Does the tach go nuts at that point tho? I mean if there was an issue with the wires crossing at the sender, wouldn't you see it at the tach cause of the needle getting pegged or jumping around?
Shadetreemechanic
Full Access Member
mine would randomly lock and unlock without any noticeable difference in the tach. I tried lots of other solutions before the tach sensor because I asssumed that a bad tach sensor would result in a bad tach
FWIW That "bad" tach sensor is now on my current IDI which has a zf. I don't notice anything out of the ordinary with the tach.
LCAM-01XA
Full Access Member
Interesting, good to know they can be so "sneaky"...
When my T.C. was unlocking and locking back up , there was a jump in R.P.M.'s. While talking to my local trans guy. He was telling me about various things that could be reason. He moved wire plug on throttle Position unit a little showing what to check. I drove in with problem and left with out, about month later it started again. So just check anything that sends info to trans, cruise-control etc. I spent 4 yrs. with problem. Dis-connecting batt only reset it for a while. I really don't know if the bare wire under bed was problem as I changed to ZF5. That was a 100% cure.
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