04 trailblazer has no forward or reverse

Discussion in 'Chevy Trailblazer Forum (GMC Envoy)' started by Treadnmud, Apr 9, 2012.

  1. Treadnmud

    Treadnmud New Member

    My brother in law just recently bought an 04 trailblazer with about 172k on it. It has the 4.2 v6 but no sure bout the trans.
    He was driving down the road when his tach revved up and he noticed he had no gears. I looked at it for him. Noticed it had way too much fluid, maybe it smelled a touch toasted. But not burnt by any means. His torque converter is spinning at least from the outside. No matter what gear you put it in the engine does not load up or otherwise give any indication that it is trying to go in gear.
    A quick scan showed no codes. I did verify that the TCC slip is identical to the engine rpm. Maybe broken input shaft, sprag, torque converter? Any ideas?
  2. Brad Preece

    Brad Preece New Member

    I'd imagine the sprag is the culprit for the initial issues. That being said, I'd say all the forward apply clutches and stills need to be replaced, along with an upgraded sun shell and all the other doo doo parts that usually go
  3. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    A broken sprag would not stop reverse from engaging. It certainly CAN end all forward motion. What is the history of the vehicle? Has it been used to tow? If so, how much weight and how frequently? Has it given any other warning signs like noises, slipping, shuddering. Has it set the check engine light? If so, what are the codes? It may be a torque converter problem. The Torque Converter is what takes the place of a clutch on an automatic transmission. If it has no pressure, insufficient pressure or insufficient fluid inside it, it will not engage the engine to the transmission. This may be why you have too much transmission fluid. There may be none getting into the torque converter, which could be a bad valve in the transmission. Sign of a broken sprag: If your transmission slips between the shift from 2nd to 3rd gears.

    BTW: the Trailblazer did not come with an available V6. It is an inline 6.

    Need... more... input!
  4. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Did you check to make sure that the driveshaft is not spinning? Might not be a trans issue at all could be the rear end. Another post thought he had a trans issue and it ended up being the rear end.
  5. triberfan

    triberfan New Member

    On our 04 I thought we had a transmission problem too, but it turned out to be a problem with the instrument cluster motors. Seemed pretty weird to me that it would have such a strong affect on the transmission. We had to have the entire cluster panel replaced and it fixed the problem.
  6. Treadnmud

    Treadnmud New Member

    Yep, u right! I keep forgetting it has a straight 6! No history on the SUV, it was bought off a car lot.

    The problem turned out to be the front pump. It pretty much exploded. We just had the entire trans rebuilt.

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