Superlift help needed!

[JRod]

Heya folks, Jared here...

 

So a year ago I bought a new style 1999 silverado 1500 ext. cab. At the time I had no idea about lifts. This truck I bought has a 6" lift, and after purchasing it I did some research and found out it was, in fact, a Superlift kit. Now, this dealership I bought the truck from quickly went out of business, and it turns out my truck had a few problems I wasn't told about. I've fixed almost all of them, except for one:

 

Front driveshaft vibration.

 

Now, I've read in the kits that the superlift kit MAY cause driveshaft vibration. This is MOST definately the case with my truck. I've got it down to a science where once it starts to vibrate, I can lift on the gas to change the torque applied to the front shaft and get it to stop vibrating. Anyway, you can see this is QUITE annoying. I've changed both front seals, hoping this somewhat helps. No dice. The ONLY thing left that I can think of is that the dealership or the previous owner never had a new longer driveshaft installed. Can anyone verify if my symptoms sound like a short shaft problem? Also, can someone with a 6" superlift kit measure the length of your front shaft, from joint centerline to joint centerline? If you're in the OC area, I'll even buy you a beer!

 

Any help on this topic would be GREATLY appreciated. THanks guys!

 

Jared

[1BADHD]

Get under your truck......if it doesnt have dual cv's on each end, you dont have the newer driveshaft. It should also be painted black.

[got dirt]

Ihave a Superlift on my 2500 HD never had a driveshaft front drive shaft problem and it is the orginal. Find a drive shaft shop and have them take a look at it. Or remove the front shaft and make sure it is the problem. Leave it out until you can get it fixed

[mayhem]

Installed a superlift 6" on my 2500HD and decided against replacing the front driveshaft to see if I really needed it. In 2x4 it is okay but in 4x4 I can only go upto 30mph before the truck starts to vibrate vilently. I have the need to drive in 4x4 during the winter where I am so I checked into it more and I found out that the angles with the factory front drivesaft is too severe and therefore you need a new one with cv's. I have mine on order now and will have it replaced next week. One thing that makes my case different from yours, though, I have the HD which I know the kits say have to have front driveshaft replaced. I didn;t think that was the case for non-HD. Hope this helps...

[1BADHD]

Your totally backwards. The 1500's require it and NOT the HD's. The reason for a new driveshaft is the Auto-Trac transfer case. The HD's dont have that option. That is not to say it cant use it, to smooth things out.........if you go over 6" then you may need one.

[JRod]

1BADHD, consider yourself my new hero.

 

My truck is a 99 1500 4x4 w/autotrac case. Pulled the shaft, nothing like you described. Called up the local parts store, they had one of those dual cardan shafts in stock, popped that in aaaannndd..

 

Beautiful. Problem solved:)

 

Thanks again guys!

 

Jared

[1BADHD]

Sweet!! Glad it worked and I could help out.

[mayhem]

1BadHd - I went to buy my lift and was told )and read myself) that the footnotes for my year HD said I needed the replacement. Quite honestly, I thought the same as you until I Got it back and found that over 30moh in 4x4 the whole rig had the shakes. I then called Superlift and they told me the same which is why I am having it installed tommorrow. I quess I will know the truth tommorrow. By the way, the truck is lifted more than 6" with the TB's up a little...

[1BADHD]

1BadHd - By the way, the truck is lifted more than 6" with the TB's up a little...

They reccomend it, BUT it is not required. Some trucks need it, some trucks dont. With our HD's the frnot shaft does not turn all the time. Only when engaged. so if you have a vib, you wont have it unless your in 4 wheeld drive. And 9 times outta 10, you wont be going fast enough in 4 wheel drive to feel the vib.

 

When I said anything over 6" of lift needs one, I meant if the front diff is actually dropped more than 6". If you crank your bars all your doing is lowering the tires more to gain lift. Not the whole from assembly. Anyway, let us know what happens and post pics when your done!!

[mayhem]

Got it back after installing the replacement front friveshaft and just like that 4x4 was a breeze. Now I have taken the 4x4 up to about 65mph and there is no vibration. I have no idea about the basis of this debate but all I know is that Before I put on the driveshaft I had no 4x4 over 30mph and now I do... Furthermore, before I had a slight "chirping" sound everytime I started up from a dead stop and now I don't so who knows???

[chvythndr]

Got it back after installing the replacement front friveshaft and just like that 4x4 was a breeze. Now I have taken the 4x4 up to about 65mph and there is no vibration. I have no idea about the basis of this debate but all I know is that Before I put on the driveshaft I had no 4x4 over 30mph and now I do... Furthermore, before I had a slight "chirping" sound everytime I started up from a dead stop and now I don't so who knows???

That chirping sound you heard sounds like the slip yoke. Mine had the same prob, and there is a TSB for a new nickle plated slip yoke that "supposedly" fixes the prob.