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My "84 Suburban 6.2-700R4 Stopped Shifting...

CORVAIRWILD

CORVAIRWILD

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In Arizona, buying another diesel Suburban
My '84 Suburban 6.2 diesel was shifting fine, (tho never had lockup), then on a trip back from Michigan to Adirondacks (2000 miles total), it quit shifting a couple hundred miles from home. It would only shift at way too hi an engine speed, and I tried rocking shifter, stabbing gas pedal, lengthening TV cable etc... After 100 terrible miles, finally in 3rd at 40mph, I took an exit to visit some friends that build '32 Fords, and all of sudden it's back to normal!

All was fine for 2 weeks until I jabbed the throttle to jump accros and intersection, and it's back to thinking I'm flooring it! I dropped the valve body, and removed a few valves, but they're a real bear to remove, and I thot I would do more harm, so I stopped. TV valve seems to move fine. I cleaned everything thoroughly, and re-assembled, also checked governor, and it's the same no shift. I replaced gov with another one, same, lengethend the TV cable, and same, but now it's hanging in 2nd unless I floor it, then the shift is way late. The pan had zero paper or brass, so I know the tranny is fine. It prolly has 80k.

I need the truck for work, but I basically drive around town in 1st gear, with the occasional shift to 2nd. At 40 it will hit 3rd, but drop back to 2nd at 35. I double checked the TV cable, and changed back to my old gov, and jacked up rear wheels to make sure it's spinning, all is normal. Any thoughts?
 

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Did you check out the tps? Make sure its got a clean transition from idle to wot, and proper voltages.
 
No tps on these. Line pressures are controlled by throttle valve and gov. All mechanical and hydraulic with the exception of the TTC solenoid which doesn't apply to the situ.

Trans has some nasty looking fluid. There is three parts to the throttle valve, the innermost smallest valve is likely the culprit. With the condition of that oil, I'd be disassembling and cleaning the VB completely.
 
is, are, was, were. There ARE three parts. Yeah. Well, 5 including the springs.

Throttle valves are susceptible to trash and getting plugged up.
 
To clarify, The tranny w the nasty fluid is the parts tranny, which is from a gas Suburban, also a newer updated '88 with the 4th accumulator. I was actually looking for the lockup solenoid, as mine didn't seem to work when I tested it, that's what I'm showing with the test leads. As it turns out, mine had no click, but was functioning. Of course if I can't drive it cause the shifting is so late, I'll have to wait to see if the lockup now works after I flushed it with cleaner.
Getting back to the prob at hand, I dis-assembled the TV valve, and except for some very minor sludge, things seemed decent. I'm quite sure it's a VB issue like 3500GMC wrote, but should I try dis-assemble it again? Or buy a reman VB? Gotta cost $250, but alot of work to see the same result...

I posted several vids, but none showing the actual valves I tinkered with..

https://www.youtube.com/watch?v=w8mlmVAtDlA

https://www.youtube.com/watch?v=YzOtJGSR0ek

https://www.youtube.com/watch?v=D-mYAUCynUU

https://www.youtube.com/watch?v=-fzF3jx98CU

https://www.youtube.com/watch?v=r7ptJGXVHAk
 
Yeah pretty much. They help with 'line rise' also in a worn bore.

Occasionally I refer to transmissions as transmitters, translators, transmixers, slushboxes.. etc. Just being a dork.
 
Update... no news lol... It's been a longgggg cold winter, and before winter I removed the servo piston on the pass side of the case, but the engine to TC strut is really in the way, so I can't put it back together, nothing looked wrong there. I do have another servo assy from the junk '88 parts tranny. I will remove the VB and mail it to a tranny shop in Hudson Florida, and they will rebuild it and I will pick it up when I am there in 3 weeks. we're driving back.
 
I just came back from a road trip to Florida, and had a friend of a friend rebuild a newer style auxiliary valve body ('86 up) 700 tranny. He also checked my old valve body and I re-installed it, and same old, no shifting.

So $900 later I will start the removal process... It was 80f yest, 46f now! And raining!

 
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