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Did I just blow up my transmission? 1991 C1500

Discussion in 'Chevy C/K Truck Forum' started by dspud, Jan 24, 2014.

  1. dspud

    dspud New Member

    Ok. I own a 1991 C1500 with the 5.7 engine. Its the automatic transmission, although I am not sure which one it is. Its the stock transmission. The truck has 122,000 miles on it. I had the transmission fluid and filter changed about 2 years ago at 105,000 miles. Other than a slight shutter at 30-40mph when I hit the gas I have never had any ongoing drivetrain issues.

    I had my truck bed fully loaded with my belongings Moving about 1200 miles. About 15 miles away from my final destination, I smell burning oil, and I look behind me to a cloud of white smoke. I pull over and raise the hood. White smoke everywhere. There is engine oil pooled up near the valve cover on the right side of the engine. Although I thought it was a little odd all that smoke came from what looked like leaked valve cover gasket oil, I ended up getting it towed, just in case. When I get to the house, I start it, and the engine turns over and runs great like always. I put it in reverse. Doesn't move. Forward. Doesn't move. I start looking under the truck. oil EVERYWHERE. check the transmission dipstick. looks pretty much empty and smells burnt. I have yet to find where the transmission oil came from to begin with. The engine oil on pooled on top by the valve covers is still a mystery. Any ideas?

    I am pretty sure my transmission is shot, but I would like to hear other opinions or other things to check before I give up and go out and start looking for a transmission.
  2. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    Have you attempted servicing the trans fluid then see if it moves?
    Id probably drop the pan, change fluid and filter, then see if its working still.
    It wont be a permanent fix but it might give you better options.
    Are you sure the oil on top is engine oil? Is it possible it could be trans fluid that overheated and came out the trans dip stick?
  3. the phantom

    the phantom Active Member 1000 Posts 100 Posts

    sounds to me like you blew a line or one rotted out. Your transmission will not work unless it has a certain amount of fluid. by the time you pulled over after seeing the white smoke it was probably low enough to where it wouldnt work anymore. If you didnt notice the transmission slipping at all then you might be able to fix your leak and refill it and it might move. But from what your describing that it smells burnt.. your probably looking at having it rebuilt with new clutch bands I call them replaced. The white smoke is probably transmission flluid hitting your exhaust when it was hot. Not the transmission smoking.
  4. dspud

    dspud New Member

    I have not done anything yet. Its just sitting in my driveway right now. I might do that just to see whats going on with it. The oil on the engine sure doesn't look like trans. fluid. And its on the opposite side of where the trans fluid dipstick is located. The only place it could have come from that I can see is the valve cover.

    - - - Updated - - -

    Well, here it what it looks like underneath. 12137319606_1b28c4ce20_b.jpg
  5. the phantom

    the phantom Active Member 1000 Posts 100 Posts

    Looks like to me that just the rear seal blew out. Its sitting there on your drive shaft. all the oil spun out onto the catalytic converter and thats the white smoke. Have to pull the driveshaft and put a new seal in there and fill up your tranny put driveshaft back in and try it. Make sure you have the fluid on the dipstick before trying to move it.
  6. dspud

    dspud New Member

    Thats what I was thinking. The parts look cheap. Guess its worth the time and the 20 bucks (not even) to replace it and see if it fixes the problem If it moves after adding fluid, I'll probably do a full trans flush and filter change.
  7. the phantom

    the phantom Active Member 1000 Posts 100 Posts

    If you felt it slip at all before you pulled over then there might be some damage. It doesnt take much to burn up the bands.. When you started it back up and it wouldnt move, as long as you didnt keep trying to do it then it may be alright. You might even just tap the old seal in real quick and fill it with fluid to make sure it moves. would kind of suck to remove the driveshaft and replace the seal if the tranny is toast. that seal looks like it might stay in long enough to try it.
  8. dspud

    dspud New Member

    Didn't notice any slip before pulling over, but definitely felt it trying to back it into the driveway after having it towed home. You can smell that burnt smell easily. Pretty sure something burnt up, just hoping a seal and new fluid will give me a little while longer with it. It was a daily driver until recently, but now it just gets used a few days a week. Hate to dump a lot of money into it right now, but I am not going out to buy another truck right now either.
  9. dspud

    dspud New Member

    UPDATE. replaced the seal. topped off the fluid. It took 6 Qts. I drove it around the block, but there is still some sort of metal grinding noise coming from the transmission that increases and decreases based on the speed of the vehicle. But it does move, thats a start!

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