I have a 02 Lightning and I have front and rear Hotchkis springs installed, Strange adjustable shocks set to 7, stock shackles, no shims, and Truck-Traks slapper bars with the snubbers 1 inch from the springs.

I just got the suspension installed last week and all is well for the most part. I have noticed a slight vibration when acceleration in a sharp turn from a dead stop. (example: Turning right at a 4 way stop) This only occurs under harder than normal acceleration,(around 1/3 throttle), occasionally when dry and often on wet roads. Under lighter thottle applications, it is smooth. I do not have any vibrations when driving in a straight line at any speed.

Is this normal due to the increased stiffness of the rear springs? I am a big boy and when I sit on the tailgate, I get hardly any movement in the suspension. I went to an empty parking lot and simulated these conditions and the vibration only occurs when the tires are at the limits of adhesion and spinning or trying to spin.

It's not a big deal but I don't want to break anything. Do I need to have my pinion angle checked? The issue began when the springs were installed so I assume it is not the diff slipping. The truck has 17,000 miles on it and has not been abused. Any opinions would help.

Randall

 

probibly the limited slip try adding modifier ar living with it they have upgrades clutch packs out there

 

It sounds like the diff, but what are the odds thjat the diff would magically break just when you install a new suspension? So I would check the suspension first.

You violated the basic scientific method by changing more than one thing. To triage your problem, I would remove the traction bars. Then I would check the pinion angle. Then I would play with the shocks, starting with a setting of 1, and increasing only one or two notches at a time.

 

Agreed, but I had a shop do the install and it was easier that way. The only real changes are the springs and shocks. I've had lowering shackles and the bars for a year with no issues.

I just took the truck for another spin and I was watching the rear tire during the turn and it is wheel hop. I guess that would rule out the diff? I assume that Hotchkis did their homework and the pinion angle is ok but I guess it needs to be checked just in case my truck is a freak. I played with the settings on the shocks and 1-3 make the rear end bounce over bumps. 4-6 are tighter but still bouncy. 7-8 feel the best to me. 9-10 are STIFF. None of the settings affected the axle hop. I also removed the snubbers from the bars and that had no affect.

I will have the pinion angle checked and see if it's off. It only happens under certain conditions (mostly wet streets) and I can live with it. I may upgrade to JLP long bars and see if that solves the problem.

 

I completely understand -- lots of times things have to be done together.

The diff chattering could in fact cause wheel hop. Diff chatter can be much more violent than you expect. It would just be odd for it to pop up for the first time after a suspension rework.

Check all of the obvious stuff also -- like making sure that the bolts are all tight, and that there is no physical contact anywhere.

 

Is it possible you simply were not driving around corners as aggressively before the new springs were installed, and now that they are you are giving it more mustard in the corners....

 

I am driving it a little harder but I have driven it hard in the past and not noticed the problem. I did a search with every term I could think of and it all points to pinion angle or diff chatter.

I will say I am very happy with the Hotchkis kit. I don't have the sway bars but handling is much improved with just the springs. The ride is stiffer but not nearly as bad as most people say it is.

 

Give it some time. In the beginning, I felt so speedy that I lied to myself about how rough the damn thing was riding. But the longer I ran it, the less I could tolerate it, and the more I realized how oversprung the truck was for the street.

I still have the Hotchkis leaves, but I'm turning them into monoleafs (should be about 140 lbs./in), with the balance made up with airbags.

 

If you can, just remove the snubbers and see if that makes a difference.

 

It is very stiff. Our roads are probably better than LA and roads but I already find myself avoiding parts of the road I would just run over in the past. I will no doubt question my intelligence after living with the Hotchkis suspension and full Bassani exhaust for a while. For the time being it puts a smile on my face to drive it.

 

I tried that and it made no difference. I also gorilla torqued all the hardware in the rear this evening and everything was tight.