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Vehicle Jerks when turned on.

Hi,
This has been going on since I bought the vehicle. When I start the vehicle and it turns over, the entire cabin Jolts. Its right when the vehicle turns on and its intermittant. I wanna say it happens 85 percent of the time and the other 15 percent it starts without a jolt.

What do you guys suppose would cause this? No error codes what so ever and it doesn't seem to be hurting the vehicle though I am curious to the cause.

Regards, and thanks in advance.

I had that very problem consistantly just the same,the problem for me went completely away since i installed a new tranny 3yrs ago.

Thanks, I wonder if it will make a difference when I install the Transgo kit to fix some idiosyncrasies with my trans in a few weeks....

Trans downshifts like a grandma on WOT sometimes and my 1-2 bump came back. Been an issue for as long as I've had the vehicle.

Quote:

Originally Posted by DrEaMsTeVe (Post 261419)

where are you getting your Transgo kit? and how much? its for the 4L60-E right?

thanks!

Yeah. It's the SK 4L60E kit. Shift Improver. I don't want a performance kit. I have the option of finding it cheap at ebay and doing it myself or going through a transmission buddy of mine for $150 part/labor.

I'm leaning on letting my trans guy do it. The instructions weren't nice to the little bit of understanding that I have regarding the transmission.

perfect!, thanks alot!

Tsb 08-07-30-026

GM TSB on the subject:

Quote:

INFORMATION Bulletin No.: 08-07-30-026

Date: May 22, 2008

Subject:
Information on Slight Vehicle Movement In Park At Start Up After Cold Soak

Models:
2009 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)
2009 and Prior HUMMER H2, H3
2009 and Prior Saab 9-7X with Automatic Transmission

Some vehicles may rock or move slightly forward or rearward while in park at start up after cold soak. This condition may be accompanied by a clunk noise. This is a slight movement that is more often seen visually, rather than felt, when viewed from the outside and using the auto-start feature, if equipped.

This slight movement is due to the residual transmission fluid in the clutch packs that creates a partial apply on start up. This movement is stopped by the parking pawl and/or transmission fluid exhausting completely from the clutch packs.

This slight movement has no adverse affects on the transmission and no repair should be attempted. This condition is normal. This can be verified by comparing with another identically built vehicle under the same cold conditions.

To prevent this condition from occurring, the parking brake should be utilized as per the Owners Manual recommendations anytime the vehicle is parked.

^^^^^ That sounds like a good source, what is it?

Quote:

Originally Posted by SWC1969 (Post 271185)

To prevent this condition from occurring, the parking brake should be utilized as per the Owners Manual recommendations anytime the vehicle is parked.

Just don't do that in sub-freezing temps. Unless you plan on calling in sick the next morning because you can't move your vehicle.:icon_doh:

Quote:

Originally Posted by okvortec (Post 271199)

^^^^^ That sounds like a good source, what is it?

That is a GM TSB (technical service bulletin). I have posted this in the past as well. It really is not much to worry about.

You could flush the transmission and fill it up with Dexron VI which is a fully synthetic transmission fluid that flows better when cold.