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Whining '94 1500SLE and my sob story

Discussion in '1992-Present Chevy & GMC models' started by Chris_T, Sep 18, 2002.

  1. Chris_T

    Chris_T 1/2 ton status

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    Whining \'94 1500SLE and my sob story

    Looking for opinions on what is wrong with my '94 2wd GMC 1500 SLE. I moved from Alberta to Missouri 2 months ago (has it been that long?) and I drove down my truck towing a 16 foot single axle camping trailer (which was a BIG mistake). Now I've never had any problems towing the trailer in the past, never put premium gas in it to tow .. but here's what's happening now.

    Somewhere in Manitoba a huge wind/rain storm came up that continued into the Dakotas. I pulled over to sleep (finally - I think I spent 45 hours getting here, 35 driving and 10 sleeping) and in the morning when I pull out the truck is making this high pitched driveline whine once it hits about 45 mph. I didn't notice it in the windstorm the previous night and I presume something went south in the headwind. Apart from being annoying as hell (turn the radio up), I'm getting worse mileage .. like WAY worse, 6 mpg or so. Check the fluid (it's an auto) .. looks OK, doesn't smell burnt, level is OK, change the air filter at a NAPA in whatever town I pass next just in case the mileage is due to all the dust whipped up, seems OK. At this point I'm hoping it's something in the rear end rather than the trans (it's probably not engine as the whine is speed-specific, not rpm specific). So I limp into town, get settled, unhook the trailer and drive around. The whine is still there, but the mileage is much more normal.

    So ..

    Some friends are going camping in southern MO, ask if I can drag the trailer out. The truck has been OK for a while .. not counting the whine .. and it isn't that far, so I say OK. On the way out any sort of hill and I drop from 60 mph down to 35 or 40, and now the engine is KNOCKING on the hills. Stop for gas, fill it with premium and the knocking goes away. get home on premium with much fewer problems (terrible mileage aside) and it's OK to run about town.

    So what's your best guess? Though I was hoping the initial whine was the rear end, aI'm since leaning towards tranny. If I had to guess I'd say that the torque convertor is slipping, causing the whine and the terrible mileage. But why the knocking on my second outing? Just bad gas? I'm also willing to entertain any other diagnoses.

    Now here's the sob story. I was going to move down with my '72 Blazer. Even went so far as to get the new gears installed as well as a tranny cooler and an in-pan trans temp sensor. Drove the '94 because it fell into my lap (Dad got a new truck), it was too good to pass on and it would be more reliable for the trip. I also left the majority of my tools in Edmonton with my '72, anticipating some sort of mechanical problem when I get around to driving it down. So now I'm here, no Blazer, no tools, and a really annoying whine.

    So, if anyone has a diagnosis, I'd love to hear it, as well as any good trans shops in the area.
     
  2. Chris_T

    Chris_T 1/2 ton status

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    Re: Whining \'94 1500SLE and my sob story

    No one?



    Still pounding PAVMENT after all this time
     
  3. ChevyHuny

    ChevyHuny 1/2 ton status

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    Re: Whining \'94 1500SLE and my sob story

    My goodness I feel so bad for you. I'm sorry your move has gone so bad. Have you gotten your tools yet? I am really not good at these sort of things but I will give it my best guess /forums/images/icons/grin.gif lol


    The mileage problem, You stated that when you unhooked your trailer the mileage got better. How heavy is your trailer? When you towed your trailer before, did you notice the same amount of mileage problem? or is this the first time?

    The knocking sounds, if it stopped once you filled it up, I would guess its a very good chance that it was gas. I have had a few cars that run horrible on regular gas (make noises or bad smells) but a lift in octane, or a better gas station (like chevron or texaco) always made the problem better for me. Has it happened anymore? Or just that one time?

    Have you had your tranny oil flushed or changed recently? If you can find a place that will do it for a reasonable price, it might be worth a shot.

    I believe you said that it only whines when you get to a certain RPM. If it is sitting in park can you push on the gas and get the RPMS up enough for the noise to start? Or does it only do it in DRIVE? If you can, just have a friend sit in the seat and push on the gas, then crawl underneath there. I have found noise problems like that by laying underneath while someone gets my RPMS up enough for the noise. (a loose cat converter for example).

    I wish I could recommend a shop for you but of course your not in my area. /forums/images/icons/frown.gif I hope things get better for you soon.
     
  4. Chris_T

    Chris_T 1/2 ton status

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    Re: Whining \'94 1500SLE and my sob story

    Usually when I tow the trailer I get somewhere around 10-15 mpg. By the end of my trip I was getting somewhere around 6 mpg. I think the trailer is in the neighborhood of 1700 lbs, but I could be way off.

    The whining is only in drive or overdrive ( I haven't downshifted it into second to check) and is when it's under load. If I ease off the gas - no whine. If I shift it into neutral and rev it to the appropriate rpms, either in my driveway or coasting in neutral on the road - no whine, so I'm thinking somewhere in the driveline after the engine (trans or rear end, leaning heavily towards trans). I don't think it's the engine because the noise starts consistantly at 45 mph, regardless of whether I'm in 3rd or OD. Everything was flushed before I headed out and yeah, it's going in to get flushed again, but if anyone has any suggestions I'd surely love to hear them before I have a tranny shop (still haven't found a good one) tell me I need a whole new trans
     

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