Paging Mister P

[CHEVY6000VHO]

Mister P,

 

To try and make a long story short, I've been battling to getting my driveline vibrations resolved for the past 3 months or so.

I've been told by quite a few people, that you may be of some assistance.

I have a 05' VHO ECSB.

I lowered the rear 3" with McGaughy adjustable shackles and hangers. Front with Belltech 2" spindles.

I've had vibration issues from the get go right after. 3 different ones actually.

One was a low speed shudder from 10-20mph, vibration under hard acceleration and another at 60-65mph.

I have since then found that 4* shims with the fat side to the front has taken out all hard acceleration vibrations.

I've also had a custom carrier bearing bracket made to allow full range adjustment of the carrier bearing.

The problem is getting this low speed 10-20mph shudder to go away.

It's only felt under normal light acceleration at those mph.

The only way it seems to start to dissapear is when you raise the carrier up very high into the truck. Though that causes another issue of putting the u-joint angles at the tranny at a bad angle. It places more than 3* of angle on them. More like 4-5*.

Is there a solution to this??? I'm at the point of surrendering to this truck already and selling it or putting it back to stock.........

Belltech says that they haven't seen a GM truck need to use a carrier bearing relocator kit with just a 3-4" rear drop.

McGaughy isn't any help at all. They are actually pretty rude.

I currently have it at a shop. They are "trying" to get this low speed shudder to go away. They think it is no big deal, but I do.

If you hold the truck at 15mph using the brake slightly, the shudder can be felt quite a bit.

I don't know what to do anymore..........

 

HELP PLEASE!!!!

 

Jim

[04CHASE]

have you got your pinion angle checked? that would be what i would check first. and if you can measure the angles of a stock truck with the same driveline as yours and try your best to mimick those . i know we used a carrier bearign relocater on a firends vho with 2 degree shims and he does not have any vibrations. maybe he will speak up and give you some advice since he has a very similar set up.

[CHEVY6000VHO]

I have found that raising the carrier bearing up gets rid of the vibrations......but the angles on the tranny u-joints go beyond the maximum working angle of 3*.

I just don't understand why these kits are sold like that, without instructing you to measure the u-joint angles at the tranny.

I had a custom one made to try and help allow the correct u-joint angles, but have yet to see that raising the carrier bearing is a good thing.

Is there no other way??

 

Jim

[misterp]

Hi - I still have driveline issues with my truck as well. Just like yourself I know the problem is pinion angle but exactly what the problem is has eluded me, and living in the sticks has not allowed much opportunity to get the truck to a bona-fide chassis engineer.

 

Sounds like you need more pinion angle, more than 4-degrees. With your foot on the brake at 15-mph you force the pinion to climb even more, probably to it's maximum travel allowed by the rubber spring bushings. My pinion angle was so far out of whack that I had to cut, move, and reweld the spring perches on the axle tube, it was off by some 9-degrees (best that we could measure anyway) and it's now better but still not right, there's a slight vibration at freeway speeds. I also think that my transmission and engine mounts both need to be lowered, but doing so will alter the front driveshaft pinion angles in my SS, so I need to take it to someone with experience. If I do need to have my drivetrain lowered in the chassis (which I'm not against) then I will have to also install E-fans. It's a sordid little soap opera.

 

McGaughys - yeah I've never heard anyone having a positive experience with them, myself included. Consider yourself lucky at being treated 'rudely', some other experiences have been very hostile.

 

Since you are 2WD (2-piece driveshaft), you have the option of putting the stock leaf spring hangers back on, then using the Belltech products to drop the rear which include a magic carrier bearing relocator that makes everything line up correctly. There is also the option of using aftermarket leaf springs (dropped springs) but you loose payload capacity doing that.

 

Sorry to not have the answers yet -

Mr. P.

Edited January 15, 2007 by misterp (see edit history)

[CHEVY6000VHO]

I already have a custom adjustable carrier bearing relocator bracket.

Raising it will require a 1/2-3/4" tranny mount spacer.

I don't see how switching to Belltech hangers will fix anything. I also have Caltracs installed, so I don't get much flex from the bushings ,just the rear ones.

Belltech's hangers will not allow the use of Caltracs without modifying their hangers.

I guess I will have to look for another shop. They don't seem to be able to fix the problem.

I will look for a chasis specific shop I guess......

This shit sucks. I will not install any of my go fast mods until the driveline is fixed.

 

Jim

Edited January 16, 2007 by CHEVY6000VHO (see edit history)

[misterp]

Yeah I hear you, being in the same boat.

 

As far as I can tell the modified front spring hanger is the culprit, it is what is rotating the pinion (mostly). The Belltech rear kit uses the stock front spring hanger, but I think new (dropped) leaf springs combined with the longer rear shackle.

 

Make sure that you do not go too far with your pinion angle, or the truck will vibrate under heavy braking.

 

Mr. P.

 

edit - just noticed you were in Houston

Edited January 16, 2007 by misterp (see edit history)

[CHEVY6000VHO]

Yeah I hear you, being in the same boat.

 

As far as I can tell the modified front spring hanger is the culprit, it is what is rotating the pinion (mostly).  The Belltech rear kit uses the stock front spring hanger, but I think new (dropped) leaf springs combined with the longer rear shackle.

 

Make sure that you do not go too far with your pinion angle, or the truck will vibrate under heavy braking.

 

Mr. P.

 

edit - just noticed you were in Houston

<{POST_SNAPBACK}>

I hear you. The only thing about the leaf spring drop is that it lowers the truck too much. It's considered a 4" drop, but it actually lowers the VHO and SS trucks a tad more than 4" in the rear. It causes the rear to sag. You have to lower the T-bars down to get a level ride. I don't want more than 3 to 3-1/2" drop in the rear. The truck sits nicely right now, but the vibrations from all of this look really isn't worth it.

Check my update in my other thread in this section. You'll see why I'm getting a bit frustrated from what a computer program anlysis told me.

 

Jim