99 Suburban towing problems

Discussion in 'GM Powertrain' started by f.p., Sep 25, 2007.

  1. f.p.

    f.p. New Member

    I own a 99 Suburban 2wd with 113,000 miles. When I tow even the smallest trailer I get a bad shudder in the front end and it feels like it is losing power going up hill. I have bought new tires and it still shudders. I have been told it may be the Torque Converter. It occurs in O/D or 3rd gear. The owners manual says tow in O/D. The vehicle does not shudder without trailer. I bought the vehicle when it was 1 year old and it has had a short whine noise from the rear end at approx. 30 and 50 mph under strain with or without a trailer. I added a small bottle of fluid at the advise of a mechanic ( The name escapes me)made by Ford into the transmission. The truck started skipping very bad and I had to get the transmission flushed, The skipping stopped and I'm back to my old problem. One time towing a small boat uphill it shudderd and the check engine light came on and went out. The code is p0430, with light off now. I believe all of this is related. Help Please!
     
  2. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    No shudder in 1st or 2nd gear, just 3rd & OD?
     
  3. collinsperformance

    collinsperformance Epic Member 5+ Years 500 Posts

    you might re-read the manual and on my door and other vehicles with OD all say "Do not tow in overdrive" this adds strain to an already weak transmission. i agree with the above as well does it do it if in drive? or in any other gear if you manually shift it? what happens if you put a few hundred pounds in the back without a trailer same thing? you checked the u-joints and slip joints?...mike
     
  4. f.p.

    f.p. New Member

    I have not tried 1st or 2nd gear to see if it does it but I will. And I have not checked u joints or slip joints. Im not much of a mechanic so Im going to take all of these suggestions to mechanic and have him check them all out. Ive had to put off getting it checked out for a short time because of work, Im just lucky it runs okay without trailer. I have not put very large loads in it without trailer so I cant say if it does it with just a few hundred pounds in back.
     
  5. 84fiero123

    84fiero123 Epic Member 5+ Years 1000 Posts Platinum Contributor

    Something as simple as a misfire on 1 plug or a vacuum leak can cause what you have mentioned and you might not notice it when not towing.
     
  6. f.p.

    f.p. New Member

    Thanks to all who posted reply. Checked gap on passenger side plugs and found one was wrong. Pulled trailer to mechanic for test drive and it drove fine. Not sure why but I guess it fixed it
     
  7. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    It is easy to overlook something as simple as plugs and wires. Especially if they were recently replaced. An unemployed friend of mine was limping around in his van wasting a ton of gas. It would accelerate poorly, but it would do 65mph eventually. Popped the hood and it was obvious that at least two of the six plug wires were bad.

    I had kept the set of 'brand new' wires that I had to replace on my burb. He was able to replace all of his wires with pieces from my set and now it runs just fine.

    btw anybody seen these plug wire splicers from NGK?
    [​IMG]
     

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