Problems after lifting truck

[Jimmy W]

Yeah, cross pin and spiders, push the axles in, pull the clips, side gears, and remove the axles shafts from the housing.

 

But there is still "play" between the end of the axle shaft and the crosspin. We aren't talking a whole lot, but that little bit of wiggle creates a lot of clunking side to side.

 

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[fondupot]

Wonder if it's your axle sliding in and out of the rear differential. I know there is a term for it. I don't know what it's called. But my friends truck did it.

 

Edit: but he had a 7" lift

 

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You're thinking of the slip yoke on the driveshaft where it meets the rear of the transmission/transfer case.

 

The axles do not slide in the differential....And the driveshaft is bolted to the rear diff via a U-Joint. The slip yoke is what allows for the driveshaft to be variable length as the rear suspension cycles.

[SouthernSilveradoGuy85]

Maybe axle wrap? Where the axle wants to twist as you give it throttle.

[Bearjew16]

Which King Shocks?

 

Sounds like your sound issue is suspension reaching end of travel going down and your shocks piston is making the sound. (very little suspension travel).

 

Take off your shocks and back down the driveway.

This is what I thought at first so I jack up the back of the truck from the hitch and I had over 3" of up travel in the shocks so I ruled that out, but unbolting them doesn't take long and I want to try it and see what happens

[Bearjew16]

I think there's some confusion here. Axles don't move in and out by design.

 

The driveshaft has to move in and out of the transmission/transfer case on a "slip yoke" as the rear axle assembly moves up and down relative to the chassis. A slip yoke slides over the splined output shaft of the transmission/transfer case and the outside diameter acts as a bearing and seal surface. The other end of the slip yoke has a fork for a universal joint that attaches to the driveshaft. Lifting a truck puts a steeper angle on the driveshaft. This puts more angular (bending) load on the universal joints and slip yoke bearing/splines. The angular load inhibits the fore and aft sliding the yoke is supposed to do. As the driveshaft turns, the u-joint loads and unloads this angular load, due to the geometry of a u-joint. When it is in a rotational position that inhibits the sliding and you move the rear axle assembly up or down (like backing out of a driveway), the slip yoke binds and can't slide in or out easily, then the driveshaft rotates slightly and unloads the yoke and it slips fore or aft, as it should, and you hear a clunk.

 

When you lift a truck, the angle of the driveshaft to the axle pinion shaft yoke and to the output shaft of the transmission/transfer case, gets steeper. A good lift kit will include shimming to rotate the rear axle where the pinion shaft is angled more upward, which reduces the relative angle of the driveshaft to the pinion shaft. However, the transmission/transfer case output shaft is often still steeper than the optimum operating angles when a truck is lifted, especially on big lifts. These extreme cases can be corrected with a 2 piece driveshaft with an extra u-joint in the middle.

 

On your 4" lift, simply lubing the inside of the splines may make the clunk go away for a while. It's a repetitive service item, even on a stock truck. Lifted trucks may need it more often.

 

Search the net on lifted truck driveshaft angles.

 

I've thought about it possibly being the driveshaft because of the new angle but from what I know about bad driveshaft angles I thought you get vibrations on the highway from it and I thought the clunking sound would come when you get it throttle, not when you go over a bump. I'm out of town now but I'll look at my angles when I get home and see how bad they are

[Bearjew16]

I just found a couple threads with pages of guys complaining about the same thing with stock leaf springs. They claim that it's the leafs moving on one another. If that's all this is then I guess I'll have to deal with it -__-

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Holy smokes I have this exact same issue and I have spent 4 months trying to chase down this problem. Three of those months my truck has been in three different dealerships in two different off-road shops throwing parts and labor at it because it's still under warranty. Nobody seems to figure it out in the dealers are absolutely the most clueless. But there seems to be some common opinion that the issue lies within the floating axle and somehow the lift is magnifying this play in the floating axle. I'm convinced it is a floating axle everything else we've tried he's not make the sound go away. Does anybody have a solution to this yet???? I'm dying to know. 

[BrightWhiteDC]

Same issue. When accelerating it clunks. Almost the same feeling when a trailer is hooked up. Dealership can't reproduce the issue but the second I drive away it is definitely notacable. The manager gets in the passenger seat, real heavy guy, and it doesn't do it.


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[Eligio Hernandez]

I have a 2010 silverado with a 9in lift the driveshaft vibrates on the road do i need a longer driveshaft and any recommendations on good ones

[tmo]

I just found a couple threads with pages of guys complaining about the same thing with stock leaf springs. They claim that it's the leafs moving on one another. If that's all this is then I guess I'll have to deal with it -__-

Mine just came back from the dealership for the leaf springs. There is a TSB out to fix them. My truck isn’t lifted, but was making the same sound. I actually thought it was my front suspension, but the dealership did the leaf spring fix and I haven’t had issues since. I would check it out, even if you are lifted they may do the fix since they know it’s an issue. The service rep acted like they had seen a lot of trucks with the same thing [emoji2371]

[Jetiemann]

First question should be why you got 4" of lift from J1 which should only give you 2". Installed properly?