gtgt_bangbang
New member
Funny story bro.
Got done with my rebuild, did a "tough love" Break in (first couple runs done at rapidly progressing higher RPMs til maybe 70% redline to create high cylinder pressure while the rings are still very early in seating, each run for 4 mile~or so nonstop blasts, quick oil change after that first session). Then everything seemed pretty damn kosher for the first two tank fulls.
Finally happened by and explored an upcountry motorcycle track which was top of a super steep but paved hill. Coming down, I wanted to avoid sucking oil up via a jake brake, so I kind of stupidly shut it off, immediately popped it in neutral, and even quicker quickly learned that coasting down that steep twisty would've been of death ride, absolutely no way to brake / steer this heavy rig. Fired it back up, popped back to Drive / lower gear roll down rest of way to highway (where only for a moment noticed a slight 'hitch' while gassing to full tilt boogie on the onramp. )
Soon back to town, naturally forced into lower gears and was having All Kinds of Scaryass problems;
in short; 1st gear off the line felt fine but at the 1~2 AND less so at 2~3 shift, it felt like the transmission was kicking, the whole rig stumbling, and the engine RPMs would drop very low (500~1000) for a couple secs, even more confounding issues.
What can I say- I freaked out. Bad. Timing of problem first occurrence, hillclimb and descent using questionable techniques, had me horrified with the worst possibilities; burnt clutch pack /band, chunks-o-monkeysnot sucked up in the valve body, etc. Visions of a scrapped truck, cursing the planet, calculating the only economical solution was to Harold&Maude&Thelma&Louise the whole rig into the Pacific...
Checked out the engine for possible reasons to explain the super low rpm's at shift, found - not much at all. (I highly recommend you get some wire harness from the junkyard to ohm out the throttle valve position sensor in particular, it's very hard to touch probes as installed)
Jumpered TE1 to E1 for a CEL code dump. No engine codes, but YIPPEE 2 transmission codes! 63 (#2 solendoid electrical, ie not mechanical , as mechanical won't report...) and 64 (LU solenoid, electrical).
You start troubleshooting solenoids with a resistance check (four sols on my late 2gen, each should be 11~15Ω, first connector breakin point located at ECM) and encouragingly found that two of the four pins were low and equal at 7Ω, the other two good around 13.
After a resistance check, you can touch 12 V to each pins and listen for solenoid actuation. Got appropriate clicks there.
Started working down the harness; the next connector is above transmission near starter, still finding 13 / 7 / 7 / 13Ω on the four wires.
and to the next Next connector, which was a trailer plug that I had recently installed (after cutting the solenoids wire oh so long ago when pulling the engine & tranny, don't know why I didn't find that upstream connector, but I am kinda sure it was late at night with a dangerously half pulled e&t, so to avoiding pulling trans pan to disconnect the solenoid wires I snipped said wires for reasons that seemed 100% expedient at the time) .
By this point I had untaped wire bundles at several points along the path from ECM to trans, and NOW resistance checks now showed all four good ~13Ω values. This is very good news, since the two bad pins Ω+Ω in parallel = 7Ω and = each other had indicated a short between these two branches, more appealing than alternative possibilty of two solenoids going bad at the same time, and thus a hopefully easy fix.
I vouch for me doing a good nuf job splicing in that trailer connector; crimped, soldered, re-crimped, shrink-tubed and taped, but I will admit now I didnt use one technique I usually favor; staggering the several (3 here) splices so they don't lie adjacent to each other, mainly to make a thinner wire bundle, but also to avoid possible future contact between the solid yet homemade joints.
Anyway the end of the troubleshooting story was spotting the smallest tiniest bittiest short I've ever seen; apparently two adjacent sharps on two splices had tunneled pinholes through the perhaps crappy quality shrink tube, and shorted out solenoid #2 to the Lock Up Solenoid.
For future researchers, that explained A LOT about how a malfunctioning tranny solenoid issue might feel; note that with this particular short, whenever the #2 solenoid kicked for low speed upshift, the lock up solenoid was getting some voltage too, which apparently made the transmission hard as hell the turn, which in turn lugged the engine rpm's down, likely sending all sorts of conflicting signals the the ECM, which sent out scatterbrained commands to the e&t.
In 1st or 3rd/OD, there was less or no apparent problem with the solenoid cross talk, until when the lock up signal inadvertently tried to engage #2 out of sequence, and transmission would again hunt for a good gear to be in.
While the precise root cause of this problem (splices working thru insulation til shorted) probably does not exist on your truck, be aware that if your tranny starts herking and jerking, it's super just super easy to meter the solenoids as a front-line check, and a common problem point.
I can only guess the transmission maybe got extra hot on that hill decline and the tightly tape wrapped wire bundle pressured two sharp spots through their shrink tubes, perhaps explaining why the symptom started at that exact time.
The picture below is of the wire short. One short is that 2 pixel large bright spot on the right hand wire, shorting to the even smaller spot on the middle wire- do not adjust your monitors, you're already looking at a magnified version cos NO my thumb aint that big.
Got done with my rebuild, did a "tough love" Break in (first couple runs done at rapidly progressing higher RPMs til maybe 70% redline to create high cylinder pressure while the rings are still very early in seating, each run for 4 mile~or so nonstop blasts, quick oil change after that first session). Then everything seemed pretty damn kosher for the first two tank fulls.
Finally happened by and explored an upcountry motorcycle track which was top of a super steep but paved hill. Coming down, I wanted to avoid sucking oil up via a jake brake, so I kind of stupidly shut it off, immediately popped it in neutral, and even quicker quickly learned that coasting down that steep twisty would've been of death ride, absolutely no way to brake / steer this heavy rig. Fired it back up, popped back to Drive / lower gear roll down rest of way to highway (where only for a moment noticed a slight 'hitch' while gassing to full tilt boogie on the onramp. )
Soon back to town, naturally forced into lower gears and was having All Kinds of Scaryass problems;
in short; 1st gear off the line felt fine but at the 1~2 AND less so at 2~3 shift, it felt like the transmission was kicking, the whole rig stumbling, and the engine RPMs would drop very low (500~1000) for a couple secs, even more confounding issues.
What can I say- I freaked out. Bad. Timing of problem first occurrence, hillclimb and descent using questionable techniques, had me horrified with the worst possibilities; burnt clutch pack /band, chunks-o-monkeysnot sucked up in the valve body, etc. Visions of a scrapped truck, cursing the planet, calculating the only economical solution was to Harold&Maude&Thelma&Louise the whole rig into the Pacific...
Checked out the engine for possible reasons to explain the super low rpm's at shift, found - not much at all. (I highly recommend you get some wire harness from the junkyard to ohm out the throttle valve position sensor in particular, it's very hard to touch probes as installed)
Jumpered TE1 to E1 for a CEL code dump. No engine codes, but YIPPEE 2 transmission codes! 63 (#2 solendoid electrical, ie not mechanical , as mechanical won't report...) and 64 (LU solenoid, electrical).
You start troubleshooting solenoids with a resistance check (four sols on my late 2gen, each should be 11~15Ω, first connector breakin point located at ECM) and encouragingly found that two of the four pins were low and equal at 7Ω, the other two good around 13.
After a resistance check, you can touch 12 V to each pins and listen for solenoid actuation. Got appropriate clicks there.
Started working down the harness; the next connector is above transmission near starter, still finding 13 / 7 / 7 / 13Ω on the four wires.
and to the next Next connector, which was a trailer plug that I had recently installed (after cutting the solenoids wire oh so long ago when pulling the engine & tranny, don't know why I didn't find that upstream connector, but I am kinda sure it was late at night with a dangerously half pulled e&t, so to avoiding pulling trans pan to disconnect the solenoid wires I snipped said wires for reasons that seemed 100% expedient at the time) .
By this point I had untaped wire bundles at several points along the path from ECM to trans, and NOW resistance checks now showed all four good ~13Ω values. This is very good news, since the two bad pins Ω+Ω in parallel = 7Ω and = each other had indicated a short between these two branches, more appealing than alternative possibilty of two solenoids going bad at the same time, and thus a hopefully easy fix.
I vouch for me doing a good nuf job splicing in that trailer connector; crimped, soldered, re-crimped, shrink-tubed and taped, but I will admit now I didnt use one technique I usually favor; staggering the several (3 here) splices so they don't lie adjacent to each other, mainly to make a thinner wire bundle, but also to avoid possible future contact between the solid yet homemade joints.
Anyway the end of the troubleshooting story was spotting the smallest tiniest bittiest short I've ever seen; apparently two adjacent sharps on two splices had tunneled pinholes through the perhaps crappy quality shrink tube, and shorted out solenoid #2 to the Lock Up Solenoid.
For future researchers, that explained A LOT about how a malfunctioning tranny solenoid issue might feel; note that with this particular short, whenever the #2 solenoid kicked for low speed upshift, the lock up solenoid was getting some voltage too, which apparently made the transmission hard as hell the turn, which in turn lugged the engine rpm's down, likely sending all sorts of conflicting signals the the ECM, which sent out scatterbrained commands to the e&t.
In 1st or 3rd/OD, there was less or no apparent problem with the solenoid cross talk, until when the lock up signal inadvertently tried to engage #2 out of sequence, and transmission would again hunt for a good gear to be in.
While the precise root cause of this problem (splices working thru insulation til shorted) probably does not exist on your truck, be aware that if your tranny starts herking and jerking, it's super just super easy to meter the solenoids as a front-line check, and a common problem point.
I can only guess the transmission maybe got extra hot on that hill decline and the tightly tape wrapped wire bundle pressured two sharp spots through their shrink tubes, perhaps explaining why the symptom started at that exact time.
The picture below is of the wire short. One short is that 2 pixel large bright spot on the right hand wire, shorting to the even smaller spot on the middle wire- do not adjust your monitors, you're already looking at a magnified version cos NO my thumb aint that big.
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