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Posted

I have a question for all of the guys out here who are mechanically inclined. Would it be possible to remove the rear drive shaft put in in 4x4 and drive to eliminate drive shaft and rear end as cause of vibes. If still present, reinstall shaft, then take out front shaft to eliminate front shaft/diff as cause? I'm almost positive this can be done but not sure what you can use in rear of trans to stop spillage of atf and also front of transfer case. Any trans gurus in this thread?

It is possible but like mentioned above if you do it yourself you have to seal the rear out put otherwise the t-case pukes out transmission fluid. Not sure how you're supposed to seal it up to prevent this, maybe there is a special part GM has that replaces the stub shaft that slides into the transfer case. You could remove the stub shaft from the drive line by pressing out the u-joint and slide it back into the t-case but I don't see how you would prevent it from falling out without the drive line to hold it in that would really suck for it to fall out at 70mph on the freeway, for you and whoever is behind you on the road, it's designed to slide in and out as the suspension cycles so there is no keeper holding it in. The front drive shaft doesn't turn when in 2wd only the front CV shafts are rotating while in 2wd.

Posted

The truck went back to tire shop today to reestablish balance, confirmed had some tires a little bit off so we trued them up again. While there, I asked can we get it up on a lift and get all tires rolling at once, we did and nothing looked bad in the driveshaft or wheel assemblies.

 

Drove into work this morning, tire vibration is better but there is still something there.. I am thinking something in torque converter... as soon as you crest a hill and plane out with little throttle input the truck has some "shuddering", full throttle no problems...

Posted

After chasing the elusive vibration issue with my 2015 Sierra crew cab short bed for most of a year, I finally expanded my search. My truck had been lowered with long shackles and shocks in the rear and a drop spindle kit in the front which did not cause my vibration issue. It also did not change the issue and I had decided to just live with it until I blew the drive shaft somewhere north of 95 mph. Lucky for me the truck had been lowered so the rear part of the drive shaft just skipped along the road surface. Now for what appears to be the fix that works for me. I found CALVERT Racing of California and got a set of Caltrac 3400's installed after making sure the pinion angle and drive line were all in specs, about 1 degree negative pinion. This seems to be the best $400.00 ever spent. No shake, No rattle, No role, No vibration all the way up and down; 0 to 112 mph anyway and no ill ride effects. The ride seems to be tighter and totally stable at all speeds. Total cost for me was about a grand and has a warranty. As far as I'm concerned GM should put Caltracs on all of their Silverado and Sierra 1500 pickups. They could probably do it for no more than a $300.00 price change out the door and make a lot more people happy.

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  • Like 1
Posted (edited)

So you are saying that your pinion angle was off? Or do you think your original driveshaft was bent or out of balance?

Edited by trik396
Posted

The original drive shaft was bad from the factory and the pinion angle was off by one degree. Replacing the drive shaft and correcting the pinion angle both did not stop the vibration. After installing the Caltracs, the vibration is gone. I don't much care what it took to correct the problem. Just came back from a drive that gave me the opportunity to get up to about 107mph and no vibration problems. It does make a slight clunk when crossing rough ground though.

Posted

Old drag racer here. Familiar with cal tracs. Also if I remember correctly you need minus 2 to 3 degrees of neg pinion. But I have no clue what specs are for our trucks

Posted

Old drag racer here. Familiar with cal tracs. Also if I remember correctly you need minus 2 to 3 degrees of neg pinion. But I have no clue what specs are for our trucks

 

Think they are saying 1 degree now for street vehicles, still 2 to 3 for drag racing.

 

Oddly enough I ordered my set of Caltracs earlier today, for different reasons mainly but also because now that I have gotten my vibration fixed I have noticed some pinion angle vibrations during coast or cruise that go away with heavy load.

Posted

Can anyone tell me where I can find information on what correct pinion angle should be?

Can anyone tell me where I can find information on what correct pinion angle should be?

Can anyone tell me where I can find information on what correct pinion angle should be?

Posted

Check out this video....

 

 

 

I had no idea there was so much wind-up of the axle housing with a leaf spring suspension! With that much angle change, how does any truck not vibrate like crazy? I would imagine the previous generation did the same thing...why no vibs there? Makes me wonder how import pinion angle really is on most vehicles.

Posted

Pinion angle is important. Yes it changes with a heavy load or hitting bumps etc but it has a range of motion that it works thru and as long as it's within spec it is smooth. If it's off from the start it doesn't work right and you can have problems with u joints and vibrations

Posted

Frame beaming is the real culprit, along with stiffer body mounts this generation truck, allowing vibrations from engine, and driveline into the cabin and steering wheel.

 

Shame on you GM.....!

 

Solutions that will help.

Balance your driveshaft, confirm run out at axle hubs, sell your oem tires buy good brand name quality ones. Run 18" rims

Add some dampening melt sheets under your carpet on the floor, this and softer body mounts will reduce these crapola problems. A good test is to clamp angle iron many c clamps or f clamps to frame and retest your vibrations.

If your vibration intensity changes you have confirmed GM's known problem!

 

Good luck

Posted

Proof that it is a frame resonance issue that can't be pinpointed?

 

 

The Silverado will ride on an all-new frame, but the truck’s basic setup—separate body and frame and a live rear axle located by leaf springs—isn’t going to change, nor will the usual choice of standard rear-wheel drive and optional four- or all-wheel drive.

 

http://www.caranddriver.com/news/2019-chevrolet-silverado-1500-spy-photos-news?src=ha_m&mag=cdb&dom=fb

 

I find it hard to believe GM would be doing an "all new" frame after only a 5-6 year run.

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