To start off, here is my truck in concern I will list the specs as well as some recent work that I have done.
92 K2500 454 ECLB 4L80E ≈280,000 miles
New Alternator
Battery Tests good
Recently rebuilt transmission by local shop
New brake switch
New IAC and relearned.
Swapped Gauge Cluster
New distributor assembly including cap/rotor.
I am currently having an issue with the transmission locking and unlocking at inappropriate times. The torque converter will unlock, then lock, unlock and lock while driving down the road at 55-60 MPH.
When I go to slow down, around 48-50 MPH the torque converter will try to engage which results in revving up the engine by 1500-1800 RPM that is how it can be noticed, it can also be felt. It will rise, then fall, rise then fall until I am out of that speed range. It will then act normal as I continue to slow down.
I took this truck back to the transmission shop as it is still under warranty. They had the truck for 2 weeks and could not diagnose and solve the issues. At all other times the transmission holds, shifts and runs great. It does not slip or have any "weak characteristics".
At the same time the truck has a high idle issue, initially idling in park at 1500 RPM replacing the IAC valve brought it down to 1,000-1,100 RPM in park and when fully warmed up it will sometimes idle around 700-800. Relearning/ replacing the IAC seemed to help the shifting. Both the transmission shop, and I believe the issue with the trans is related to the high idle. I.E. because the idle is so high the trans think there is higher rpm or load wanting to be applied, therefore it tries to engage the trans while slowing down. However, could this also cause the issue with the torque converter locking and unlocking while at cruising speeds?
Lastly, it seems that the truck acts up the most when there is a weird electrical issue involving my gauge cluster, the rpm and speedometer will bounce around and also "blink" when my turn signal is on. The blower motor (new) will slow down when I come to a stop and sometimes the speakers for the radio will slightly cut in/out when this happens.
All in all there is a lot going on with it and I have a gut feeling it is something simple such as a ground or bad battery. I am going to replace the battery this evening with a known good one to see if that helps. The idle is still a little high so I think I am going to try and relearn the IAC and set it even lower as well as try to relearn the TPS.
Some advice would be greatly appreciated, thanks!
Here's a pic of the rig in question.
92 K2500 454 ECLB 4L80E ≈280,000 miles
New Alternator
Battery Tests good
Recently rebuilt transmission by local shop
New brake switch
New IAC and relearned.
Swapped Gauge Cluster
New distributor assembly including cap/rotor.
I am currently having an issue with the transmission locking and unlocking at inappropriate times. The torque converter will unlock, then lock, unlock and lock while driving down the road at 55-60 MPH.
When I go to slow down, around 48-50 MPH the torque converter will try to engage which results in revving up the engine by 1500-1800 RPM that is how it can be noticed, it can also be felt. It will rise, then fall, rise then fall until I am out of that speed range. It will then act normal as I continue to slow down.
I took this truck back to the transmission shop as it is still under warranty. They had the truck for 2 weeks and could not diagnose and solve the issues. At all other times the transmission holds, shifts and runs great. It does not slip or have any "weak characteristics".
At the same time the truck has a high idle issue, initially idling in park at 1500 RPM replacing the IAC valve brought it down to 1,000-1,100 RPM in park and when fully warmed up it will sometimes idle around 700-800. Relearning/ replacing the IAC seemed to help the shifting. Both the transmission shop, and I believe the issue with the trans is related to the high idle. I.E. because the idle is so high the trans think there is higher rpm or load wanting to be applied, therefore it tries to engage the trans while slowing down. However, could this also cause the issue with the torque converter locking and unlocking while at cruising speeds?
Lastly, it seems that the truck acts up the most when there is a weird electrical issue involving my gauge cluster, the rpm and speedometer will bounce around and also "blink" when my turn signal is on. The blower motor (new) will slow down when I come to a stop and sometimes the speakers for the radio will slightly cut in/out when this happens.
All in all there is a lot going on with it and I have a gut feeling it is something simple such as a ground or bad battery. I am going to replace the battery this evening with a known good one to see if that helps. The idle is still a little high so I think I am going to try and relearn the IAC and set it even lower as well as try to relearn the TPS.
Some advice would be greatly appreciated, thanks!
Here's a pic of the rig in question.
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