Starting Issue ?

mattymax · April 28, 2011

2007 NBS 5.3 26K miles

Cold/warm engine, warm out, start the truck and it seems like it jolts foward when it starts. It makes the entire truck move, but it doesnt happen every time.

I had this issue on my 2002 Silverado but it was only when it was COLD COLD.

Not sure if its a problem or not. It starts great without a problem

-matt

mattymax · April 29, 2011

No ideas ??

miltoney · May 20, 2011

Ive experienced the same thing a couple times in the last couple weeks...as soon as the engine starts it feels like the drive shaft was engaged and it jolts the truck so hard it rocks for a couple seconds...anyone else experience this?

tesnoboy · May 20, 2011

Ive experienced the same thing a couple times in the last couple weeks...as soon as the engine starts it feels like the drive shaft was engaged and it jolts the truck so hard it rocks for a couple seconds...anyone else experience this?

I have had this happen to me a couple of times. Not as hard as you have described though. Mine felt like the starter was loose or something, but nothing was.

jro909 · May 20, 2011

happens to me very rarely on my 04, i think its just the inertia generated by the high rev on start up and the slack on the parking pinion

mhenshaw · May 20, 2011

Mine does it every so often too.

mattymax · May 20, 2011

Yea mine def doesnt do it EVERY time. Even if it sits for a few days, its hit or miss

-matt

RaddHazzard · May 20, 2011

Mine does too, about one in 15 starts. I asked this question to Justin at BB because it did it with one of the data logging drives I did. He said maybe the ac compressor engaging immediately after startup. It actually rocks my truck back and forth real hard. I also have an audible click sound along with it.

Duelin · May 21, 2011

This is an old post from Jan. 28, 2009. Posted by Bordi.

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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.