Manual Transmission Problems

SuperGMC · December 5, 2011

Hello Everyone, I am hoping that someone can help point me in the right direction. I have a 07 GMC Sierra that is having transmission trouble. No matter what gear you are in if you let off the accelerator the truck has a noticeable bucking feeling. I haven't ever heard much noise from underneath the truck when it is doing this. The truck will also jerk/buck a little when you push accelerator in.

I thought it was cured as it hasn't done this since I received it back from the mechanic, but now it has started back.

Any help is appreciated!

Stevens03 · December 6, 2011

Possible drive line slack Have you had all the u-joints checked, maybe repacked the slip yoke with some grease? Does it shutter any when your pulling out from a stop?

What work did the mechanic do?

SuperGMC · December 6, 2011

Thanks for the reply!

He replaced the ingition switch and ingition coil. He checked out the driveshaft and said that everything was tight.

The jerking/bucking went away for a few days after the switch replacement. It just started doing it on my way home this evening. I asked him to check it out while it was up there, he couldn't replicate the problem. He suspected that perhaps the ingition switch was shorting out and trying to shut off the engine as I was driving. I dunno.

SuperGMC · December 23, 2011

I figured out a solution to this.

Turns out that there is absolutely nothing wrong with my transmission. It finally hit me that the problem only happens when it rains. After the engine heats up the truck runs fine. I did a tune up on my ignition system and it is running like a top. It jerks a little when slowing down from any speed over 40mph, but it has done that since the day I bought it.

It seems to be A-OK now.