1990 700R4 need help troubleshooting it.

I have a 1990 2500 Chevrolet truck I bought and just stared using with a snow plow. When I bought it it would not shift out of 1st gear. Fluid was just changed by the farmer that had it along with the filter. A freind of mine picked it up for me and took it to his shop and changed the governor in it with a "spare" from the "Automotive recycling yard" out back of his shop with one of "unknow origin." I really needed to get it on the road as snow was on the way and at $100 hour, if it would just work long enough to get through one or snow storms I'd replace it. After the governor change, it would shift, it made you start to wonder if it would at light/part throttle but it would shift on out OK. Now it's starting to make me wonder, at part throttle, it stays in first up until about 30-35 MPH, then shifts to 2nd, stays there up until about 50-60 MPH. If you go WOT, it shifts at about the same MPH, very firm, neck snapping shifts. The fluid does not smell burned, yet. I'm wondering if I can fix it in the truck without having to pull it out? I think the previous owner had it rebuilt in january of '08. It remminds me of when I had a BB code T-400 behind a V-6 in my old ProStreet car and we found out the modulator vacuum line was crimped closed. It had high shift points and VERY firm ones too, it'd chirp the 21.5x33x15 MT tires if you turned it on up in 6-7000 RPM range. So if any of you slush box gurus have any ideas, I'm open for suggestions. I'm heading to someplace in Virgina in the next day or two to work for some local municipalaity pushing snow, 2-300 mile o/w trip from the sounds of it.

 

Sounds like a throttle valve or a t.v. cable problem. Check the T.V. cable adjustment first. If it's OK, disconnect the cable from the throttle linkage and pull it manually, should feel smooth and tension will increase the more you pull on it. You may have to drop the pan and check to see if the linkage is operating properly. Check the governor you took out by holding it by the gear vertically and move the weights inward. The valve in the center should move up and down as you move the weights in and out. Could also be a stuck pressure regulator valve. Does it downshift hard and too early?

 

It seems to downshift fine, I don't think it's a hard down shift when it goes from drive or second back to 1st, but then again, I give everything hell, so it'd have to about knock my teeth out to think it was hard. How do you check the Throttle valve and cable adjustment?

 

There is a web site called tv made easy, google it. They explain it much better than I ever could. Good luck.

 

I had the same thing going on with my 91 2500 4x4. I also replaced the governer and it still shifted late and HARD. My TV cable was the cause and after reading this article here I had it shifting perfectly in 5 minutes. Re-set the cable acording to the instructions on this link and you should be fine. 1 year later it still shifts perfectly.

This was my issue and it is the same as you describe:

"The other incorrect TV set up condition is what we call Long Spring Syndrome (LSS). This condition exists when the TV valve is positioned in such a way as to cause TV feed fluid to be prematurely feeding into the TV feed orifice. This condition will be influencing the transmissions control circuits even though the accelerator pedal is still in its idle position. We know of four things that will normally cause the LSS "illness". First is when the vehicles accelerator pedal will not rotate the "carburetor linkage" to its full W.O.T. position and the accelerator pedal is then used during a factory "set" procedure to "set" the W.O.T. position. Second cause would be a "carburetor linkage" which causes the TV cable to return a distance shorter than required to position the TV valve at its correct starting position. Third is a TV spring that's too long which subsequently will not allow the TV valve to position correctly at the edge of the TV feed orifice. This LSS condition rarely causes damage but can result in some very frustrating behavior. LSS causes the TV valve to be positioned in such a way as to allow TV feed fluid pressure and volume to feed into the TV feed passage before the accelerator pedal is depressed at all! This condition signals for higher line pressures and instructs the up shift control circuits to start delaying the up shift timing before the accelerator pedal is even depressed at all! Common symptoms of LSS are late hard up shifts compared to the accelerator pedal position during light to medium throttle driving situations. Late hard shifts during light throttle driving situations gets very old in a hurry. Downshifting may occur too early and can sometimes causes "shuttling" between overdrive (4th) and 3rd gears. The transmission may produce double down shifts at inappropriate times, of example, it shifts from overdrive (4th) down to second gear (2nd) gear when a shift into third (3rd) would have been far more appropriate."


And here was the fix:

http://www.tvmadeez.com/article/index.php

 

Also, check your routing for the TV cable. I had one get pinched between the trans and the floorpan once. Broke a motor mount and it'd pinch the cable, and it made the truck shift hard all the time. I got a new cable, re-routed it and zip-tied it into place.

-Josh

 

I'll probably get around to it after this next round of snow is over with. I just got back from the Va./DC area tonight to get ready for the snow here. I used a buddy's plow truck up there. I wish I'd taken my camera with me. One guy that I was plowing out his subdivision told me the truck I was plowing with, the rear tires would come 2 feet off the ground when I'd plow into a snow bank. I had a salt spreader mounted on the rear of a '85 3/4 ton Chevy, full of salt. This was not a tail gate spreader, it was a full body spreader. I've got to fix everything for the guy tonight if I can. The body's loose on the chassis, gear selector will not go into park, Plow pump broke off the engine, spreader will not start and the RR fender got torn loose, all the rear tail lights are either knocked of or out, exhaust system wa torn loose just to name a few things. O yeah, the brakes quit too, I drove it for two days with no brakes for the most part.

 

WOW, my 91 runs perfectly.

 

Do you run a Plow truck too?