Strange Transmission Operation


Original poster
Dec 4, 2011
Hello all,

Last night while driving on the farm I noticed something very peculiar. I normally keep the gear selector in 1 while on the farm to limit my speed, keep a constant max torque, and have engine breaking. Well this night for what ever reason I put the gear shifter in the 2 position.

Well I noticed when I would take off from a stop, there was absolutely no power till the revs got around 1.5k. The truck would just mush forward instead of a nice crisp roll forward. It felt as if you would slowly release the clutch on a manual car. As if you were to engage the clutch just a little so it would push the car forward, but with very little power since the clutch is only partially engaged. Then once you engage the clutch all the way all the power is there, and everything is as expected. It even feels like it is starting in second gear, totally skipping first.

If I put the selector in 1,3, or D it is a very firm and crisp take off. But in the 2 gear selector it is very mushy as if it is not fully engaging or if it is actually starting in second gear.

The lack of power does not feel like the tranny is slipping, and the this does not occur in any other gear selection, plus the fluid is only 10k old and clean.

I can even start an acceleration with the selector in the 2nd position and shift it to any other gear selector spot and there is a noticeable clunk and my power is back to what is expected.

My scan guage show's a - when in the 2nd gear selection, but it correctly shows gears in all the other gear selections.

The only rhyme or reason I could see is that our transmissions are programmed to be only in second gear when put manually put in the second gear selection to act as a "snow" gear. (This is where an automatic transmission starts off in a higher gear, usually 2nd or 3rd to send less torque to the wheels so you have less of a chance slipping on snow or ice when you accelerate from a stop) I have seen this on a few older chevys and honda's but I have never heard about this on a Trailblazer.

Help, insight, or thought would be greatly appreciated.



Nov 18, 2011
It is in the design of our trucks. It locks into 2nd only so it does not down shift into first, thus the sluggish off line performance. It is to help with snow I believe.

I think in 4-lo however that it will shift between 1st and 2nd even with shifter in 2.

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