NO 3rd or 4th

[rjwest]

Friend lost 3-4 gear. shifts in 2nd real hard.

Any guess ( 2000 3/4 ton , 4 wd )

[wushaw]

Sounds like a rebuild is in order.
Has he checked his fluid to see if burnt?
Has he been hammering it?
Was it slipping prior to this?

[Flyboy]

I had the same thing on a '93. It was the throttle position sensor on the injector pump.

[dmaxalliTech]

hmmm, thats 4l80 country there. Fluid condition? any codes?

[rjwest]

Fluid is Good, No Codes.....

When it occurs, it's right after the Dash Instruments go to " Zero " than Back on.

He just told me it's been doing this since last year.

Dealer has fixed many Wires...etc.... was good for
6 months , now worse . ( lost only Lock up )
before....Now 3 & 4 ...is going olso......


Seems to reset when key turned off.....
Electrical Gremlins ????????

[dmaxalliTech]

Yes Alex, I will take "ignition switch" for the win

[cruzer]

It happened to my 4L80E. I had 1st & 2nd only,when it did shift it would be hard(limp mode), and no speedo/gauges.When trans was cold it shifted thru all gears.It was the rear speed sensor. There are 2, 1 in frt figures input and the rear one figures shift and speedo. Both speed sensors are the same part #. I replaced then to get it to function properly disconnect batts to reboot computer.

They are located on drivers side, IIRC w/2wires going to them and a 10mm retaining bolt.

[rjwest]

CRUZER,(Thanks) Why would gages go out for speedo sender?
Are they on same circuit?. This may explain why
having problem..... Only occurs when gages go to zero for a few seconds, than limp mode/no shift.....

May be intermittent short in sender or wires...
But it does not blow a fuse.....

I don't have a circuit diagram.....

[cruzer]

RJWest, To the best of my recollection that's what happened. Maybe it was only the Speedo. When it did happen, I called a friend of mine who is a Mr Goodwrench, He told me what was wrong after I described the condition. He also said it might be a good idea to have a spare sensor in the glovebox. I take that as it is a fairly common problem. He also said the 4L80E is a very tough trans and most problems with them is electronic.I do know all the other symptoms you describe was dead on mine. I had to drive about 50miles in 2nd gear w/trailer to find an open parts dept at a dealership on Memorial Day weekend. I had a hard time finding 1 in the hills of KY and I was about 150 miles from home. The sensor was about $50. I do have 1 in the glove box now.It seemed like it was a cheesy way to ruin 1 day of a 3 day weekend.
Remember if you replace it you may have to reboot the computer by disconnecting the batteries,or at least I did.

I don't think it is the TPS. After replacing my IP
I did not calibrate the TPS. The syptom I got was no OD, hard shifting and a buzz in the trans which was high pressure. I calibrated it & all is well. I wouldn't think a 2000 has a TPS.I have read past post about the Ing switch though, but I can't recall all the symptoms. Maybe someone else can chime in on symptoms or codes.

[rjwest]

Took it to dealer, They changed the cable in steering column. ???? if fixed this time...
This is there 4 attempt to fix.....
At least there are not charging him....

[jharl@harrelsons.com]

I have a 1993 GM C3500 6.5TD with a 4l80-e. Where is the tps located?

[Flyboy]

On the side of the injector pump where throttle linkage operates the switch. I don't remember which side.