Slight lurch upon startup...

Ok so lately I have noticed that when I start my truck, it will slightly jump forward. It's barely noticeable, but I notice even the smallest of things that are out of the ordinary... What could be the problem?

Is it fate that I just saw a very nice looking, higher mileage, 2001 Blazer Trailblazer for dirt cheap at a local used car lot?... Only thing I could see wrong with it was a bit of rust on the doors down on the lower front corner. Nothing that I couldn't get fixed for dirt cheap.

Ya got me stumped!
Is this with the truck in park? No codes? Trans oil clean?

Yup, it's on initial startup. It doesn't do it all the time. Seems really erratic. No codes either, just scanned it before I posted.

Transmission was serviced around 4000 miles ago. I need to drop the pan again anyway to install a drain plug.

Strange. Is this on the Bravada? or did you buy a trail Blazer?

It's on the Bravada.

I just stopped in and looked at an '01 Blazer Trailblazer on a used car lot at lunch today. But, its a lot more miles than my Bravada has (125k miles vs 82k miles on the Bravada) and it needs ball joints, brakes, shocks, full tune up, and it may have a rear main seal leak. All for $4900... Oh yeah, needs tires too! LOL. And I already mentioned the rust...

check your shift linkage. my jimmy used to do that all the time..lurch forward a small bit when i started it.

My 2000 blazer does the exact same thing. It just rocks forward a bit on startup. It never worries me though, I've come to accept it as a characteristic of the vehicle.

Ha. My truck is just saying 'Hello!' LMAO

Or it is dry heaving. :)

I dont think its anything to worry about. Mine does it too once in a while. More so when cold.

Yeah, I just started noticing it since it's gotten colder out. Didn't notice it at all last winter, but then again, I didn't drive it a bunch last winter either. I have been driving it for the past 3 weeks as I procrastinate on getting my door weather deflectors resealed on my Bonneville.

I have seen this to be more common in the electronic controled transmissions.

If the history of the torque converter serves me right, it has to do with the TCC (torque converter clutch) controler.

Its a GM thing. SUPPER common with the mini vans, lumina, corsica, ect....

Some are corrected by doing fluid and filter changes, most need that TCC changed out (some who don't, end up changing out the trany) due to the torque converter takes out the trany.

On most 95's and up also check your shifter cable (could be signs of the cable has too much play). Not fully engaging in park. And there is no adjusting the cable, it's either right or wrong (replacement only).

EDIT:

Oh and I am surprised that the mechanics here (there are a few ASE Cert. ones) have not posted this due to it is a very common issue with GM's.