Trans Slipping? And Other Stuff

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I just bought a 2004 silverado 1500 w/ 5.3 and it is a super truck, except that in both 2nd and 3rd gear, under heavy acceleration, I feel bad vibrations from about 3500 all the way up. Trans fluid looks/smells great, full to the top. ive got about 120k on the clock. I also note that I have a 2006 2500 express with a 4.8 and it is nowhere the machine that the truck is-the silverado has a LOT more push to it. It appears stock, except that the last bozo drilled about 20 holes in the muffler to give it a throaty tone (it worked). Could the 5.3 be that much stronger than the 4.8? Is it just cause the 5.3 is a little uncorked?

[Nytemare]

5.3 has a fair bit more punch than a 4.8 to begin with. Also...the truck has better aerodynamics than the van... ...wow that was hard to say...and the truck probably weighs a little less.

 

Also you most likely have either 3.73 or 4.10 gears with a 5.3 where your van probably has 3.23's or 3.47's

 

You never know, the guy may have tuned the ECM also.

 

 

As for the trans....you may just have your U-joints on the way out... drive down the highway at 50 and slightly accelerate you should get the same vibration if they are bad.

If its pulling hard its not slipping....you can tell when its slipping.

 

This vibration could also be caused by engine mounts, or trans mounts

[txab]

Edit: Too slow this AM. ^^^beat me to it.

 

The Silverado may have a better rear gear ratio giving it more pep along with the slightly larger engine displacement.

[alwcurlz]

I just bought a 2004 silverado 1500 w/ 5.3 and it is a super truck, except that in both 2nd and 3rd gear, under heavy acceleration, I feel bad vibrations from about 3500 all the way up. Trans fluid looks/smells great, full to the top. ive got about 120k on the clock. I also note that I have a 2006 2500 express with a 4.8 and it is nowhere the machine that the truck is-the silverado has a LOT more push to it. It appears stock, except that the last bozo drilled about 20 holes in the muffler to give it a throaty tone (it worked). Could the 5.3 be that much stronger than the 4.8? Is it just cause the 5.3 is a little uncorked?

 

Few questions here...

Is there a vibration at that rpm when in park? Does it vibrate at that rpm if you manually select 1st 2nd or 3rd? Could be a number of things ranging from motor/tranny mounts or what is most likely a damaged/cracked flexplate/flywheel. I would check these things out before running it too hard and having a big crash/bang underneath the floor.

[gmtech4]

5.3 has a fair bit more punch than a 4.8 to begin with. Also...the truck has better aerodynamics than the van... ...wow that was hard to say...and the truck probably weighs a little less.

 

Also you most likely have either 3.73 or 4.10 gears with a 5.3 where your van probably has 3.23's or 3.47's

 

You never know, the guy may have tuned the ECM also.

 

 

As for the trans....you may just have your U-joints on the way out... drive down the highway at 50 and slightly accelerate you should get the same vibration if they are bad.

If its pulling hard its not slipping....you can tell when its slipping.

 

This vibration could also be caused by engine mounts, or trans mounts

 

 

 

+ 1 ,on the u-joints ,there may be a low speed squeak(rotational) as well,pull the rear shaft and rotate them ,easy,just block the wheels in neutral so the shaft isn't strained and reassembly is easy sleazy lol,