'98 Tahoe Clunk Jerk Pop Noise few seconds after Startup

[atxballer]

Hey Fellow Tahoe Owners! I have a '98 Tahoe 2DR 2WD with the 5.7L Vortec with an auto transmission. The problem I have occurs a few seconds after the engine is fired up. You can feel the Tahoe jerk as if it wants to back up, almost feels like someone is pushing the car from the front. Could it be that something is trying to engage?

In that same instant there is a sound coming right behind the middle of the dash (near the engine) that is very similar to someone popping a dent out. Imagine someone popping a dent out of a Rubbermaid garbage and that would be a sound similar to the one I hear. I wish there was another way I could describe the noise but that's what it sounds like to me. The noise happens once and it's only for a split second.

It usually occurs the first time it is started each morning or sometime later in the day if it has not been run for awhile. It also seems to happen more often when the weather is cooler. This happens in PARK,with or without the parking brake set and with or without my foot on the brake pedal. It does not happen every time which has made troubleshooting a little cumbersome.

Whatever, the noise/jerk is it doesn't seem to affect the drive ability of the vehicle at all. The Tahoe has over 130k miles but this has been going on intermittently for a long time (since ~75k). I am the original owner and at times when I have had servicing for something else I try to get them to diagnose this but of course it never replicates itself.

If anyone has any idea what this might be or if you have had something similar I would really appreciate your feedback! Thanks!

 

[Slammed]

very odd I would say it was the 4wd disengaging but you have 2wd so I am at a loss

 

[Rick90467]

I would guess worn or cracked motor mount, when the engine moves a bit your linkage may try to engage the tranny. Or maybe just a worn/misalgned linkage joint.

 

[thekl0wn]

The lunging sounds like my truck... It does this every once in a while.

If it's just a loud popping, then you might need to charge your AC system. I'm guessing you leave the defrost on? If so, try shutting it down with the AC/defrost turned off. If it doesn't do it, then I'd guess that you might need a bit of a charge... Don't know the technical explanation, but I've had this issue before, and heard of others with the same thing.

 

[skimo]

I have a 97 Z71 2 dr....I ordered mine. When I had about 80 miles on it mine did the same thing. I took it back several times and they heard it. Forgive me that I dont know what the actual term is but I was told by three different dealerships(even one 200 miles away when I went on a trip-thought I would ask them) that this was normal because of the Votec Engine/Transmission. I have 140,000 miles and finally had to change my Transmission at 120,000. The transmission person told me that sound was normal (even tho it sound bad) and it had nothing to do with my transmission get replaced. New transmission........still hear the "clunking". Hope this eases your mind

 

[azfitch]

In that same instant there is a sound coming right behind the middle of the dash (near the engine) that is very similar to someone popping a dent out. Imagine someone popping a dent out of a Rubbermaid garbage and that would be a sound similar to the one I hear. I wish there was another way I could describe the noise but that's what it sounds like to me. The noise happens once and it's only for a split second.


I have the same problem with my 05 5.3 tahoe. It only clunks after the truck has been sitting for a while. Ive tried turning off the a/c on startup and it still makes the same sound. It only clunks about a .5 second after startup and is very brief. Any ideas?