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Transmission diagnosis

Discussion in 'Chevy Trucks' started by MTCK, Nov 20, 2001.

  1. MTCK

    MTCK Senior Member
    Messages: 346

    Well, I'm back in AK for turkey, but unfortulatelly it's turning into a working trip. I took my truck for a drive yesterday, if you'll recall my earlier post about the transmission supposedly being gone, and it didn't do what I expected. It is a 700r4 and went through the first two gears totally normally. Then when it shifted to third, it was as if it was in neutral, no shaking vibrating or anything, just totally smooth reving. I planted the gas to see if that would change, and around 3500 RPM, on the way up, it caught and took off, which suprised the hell out of me. Do I have a problem with my valving? Or are the clutches really gone and this is just a symptom. The fluid level is proper, and smells every so slightly burnt, but not bad at all. Not anything like it did the LAST time this thing went south. Any thoughts?


    Ah, sidenote: also I was very pleased to find that the dealership it was taken to when I was gone left the windows down in a rain storm or something, and there's mold growing on the seatbelts, all the gauges have condensation in them, and the whole interior is soaked. Blinker indicators don't work, neither do the power windows. Now the whole interior is torn apart and it's in the heated garage trying to dry out. Not too happy about that. Look what happens when you leave for a couple months........
     
  2. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    If your 3-4 clutch pack isnt burnt,the seal is bad,at 3500rpm's you ve got enought fluid flow(GPM,to blow fluid past the leaky seal,and still engage the 3-4 clutch pack.When they pull it apart,they will air test the seals,and that one will be smoked.There is anothe possiblity,the later models have auxilary valve bodies,early models have a block off plate where the later models have an aux valve body,if these bolts back off.,or the separator plate gasket goes bad,the tranny wil do what you described.That can be checked by dropping the pan.i warn you though,dont rev it up to engage it again,because if its just the aux valve body,you wil fry the clutch pack and have to rebuild it anyway.Good luck.
     
  3. MTCK

    MTCK Senior Member
    Messages: 346

    Thanks John, I'll drop the pan tonight and have a look at that. It sure would be nice to tighten a few bolts down and have this thing back. Thanks again.

    MT
     
  4. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    The aux valve body is at the very rear of the transmission pan,I think its held on with 4 -6 bolts,it will be a block of plate,or it will have an oil feed running to it from the front pump if it has an aux valve body.Check those first,good luck.
     
  5. MTCK

    MTCK Senior Member
    Messages: 346

    Hey, the plate was there, intact and tight. Fluid was more burnt than I thought, and stunk up the garage something fierce. As I investigated further, I got under the hood and found the TV cable to be fraid and snapped in two right behind the attachment the the throttle to the carb. I'm sure it was OK when I left this fall, and the truck only has another 100 miles or so on it, but I suppose this goes to show how important it is to have this adjusted correctly. I guess I'm in the market for a new transmission. Thanks for your help John.

    Marcus