2nd Gen Non-Engine/Transmission Still Shakin' Too!

[wilsonsh]

I'm gonna start my own thread here... I kinda hi-jacked BEnglish's so I don't want to give him any more reason to put out a "hit" on me! Plus, I think we have different issues.



Anyhow, I'll just repost here what's going on for me so you don't have to flip back and forth:



Been chasing a vibration problem between 40-50 and 65+mph. It seems to be in the rear end since the vibration can be felt in the seat and, when I have something in the bed I can watch, it will shake the load with the vibration. At 40-50 mph the shake is more of a bounce and 65+ the bounce starts to pick up frequency on up to just a vibration in the floorboard. I also just replaced my tires with BFG ATs (285/75/15) about 6k miles ago.



I've recently been following up on the bad tires theory and had an axle and frame shop take a look at it. They said(and showed me) out of round tires.



Then, I got a second opinion the next day at a "name brand" shop. Had them dismount all tires from rims and check wheels for bend or whatever. Remounted and balanced and found no bad wheels but a couple tires were minimally out of round according to their standards but, indeed, out of round. They also inspected the driveline, wheels, and whatever else and found nothing loose... in fact everything was in very good shape.



Well, got a chance to get down to the dealer I bought the tires from today. Talked to the tech and he took a ride, came back and put the truck up on the frame jack and removed and checked all the tires/wheels on road force balancer. He agreed that there were two tires that were slightly out of round and replaced them. Took it for a spin real quick and all is well.



NOW, the tire shop is about 40 min from my house so I had plenty of opportunity to check the balance of the new tires. As I kept going, THE VIBRATION CAME BACK!! I'm tellin ya, I had a chance to check the vibration between 40-50 and again at 65+mph RIGHT AS I DROVE OFF THE SHOP LOT and it was nill... NO VIBRATION! The further I drove, the more the vibration came back! As I drove down the final stretch of 65+mph road 5min from my house, the vibration was in full effect, just as before.



Could this vibration have been "reset" when the truck was lifted by the frame lift at the tire shop? I'm really leaning towards control arm bushings at this point... whadduya think? There is play in the steering but, with the help of a friend, the steering box was identified as the weak link. I have been reading old threads of guys who thought the vibration was in the rear but ended up being first signs of death wobble. The steering wheel does NOT shake when the vibration appears. I've had nothing but steering issues ever since I bought this truck 25k ago and have replaced:



-ball joints

-all tie-rods/drag links

-aftermarket trackbar(DT ProFab)

-steering stabilizer

-both front and rear driveshafts fully rebuilt and balanced



I'm thinking caster shimmy from weak control arm bushings but need input. The way I understand it, there really isn't a way to check them other than pull 'em out.



Thoughts?

 

[keioga]

how about u-joints? Mine went out at 60000 ended up buying new tires only to have the vibration come back, ended up being a ujoint

 

[wilsonsh]

propeller shaft ujoints or driveshaft?

 

[EDembowski]

The only fix for an out of round tire is to make it round. I'm telling you from experience with my BFG 315s. I spent at least a thousand $$$ in my time alone trying to chase this problem down. Tried Force Balance, Centramatics, U-Joints Drive shaft balance, etc. . Turned out I found a shop that Trues/shaves tires. Problem fixed. I couldn't believe I was driving the same truck. When I get a new set of tires, I'm going straight to his shop, and letting him true em' up. Your symptoms match exactly to the ones I had. I think there are very few shops that do this any more but look around, some people call it truing or shaving the tire, basically it's a tire lathe. You might try a high performance shop or even someone that deals with the big rig tires. Good Luck!

 

[BEnglish]

Perhaps the parts (what ever is shaking or allowing the shake) is tighter when its cool and as it builds heat from the shake it allows more movement?



I have updates in still shakin’ one. LOL

 

[wilsonsh]

Yep, that's kinda what I thought as well... you can feel the vibe at first and it gets worse the longer you drive it. The control arm bushings shouldn't cost too much so I'm gonna go that route for now.



Thanks B!

 

[BEnglish]

Yep, that's kinda what I thought as well... you can feel the vibe at first and it gets worse the longer you drive it. The control arm bushings shouldn't cost too much so I'm gonna go that route for now.



Thanks B!

i have replaced mine (lowers) and i am convinced it is the sector shaft now (see "still shakin' 1")

 

[EDembowski]

I hate to beat a dead horse, but tires heat up as you drive. Spend the $65 or so and make those tires round.

 

[J.BURCHFIELD]

I have had out of round tires a time or two. A quick way to check jack the wheel off the ground and put a block next to the tread after some adjusting of the block you may see a little space and the space close up as you rotate the wheel/tire. A 32nd of an inch gap is borderline and might vibrate at 60 or above 70 mph. A 16th of an inch and it vibrates like hell. One of the reasons I prefer Michelins, they are seldom out of round and require less weight to balance. The Shops that shave tires are few and far between. In the old days they were more of them but as tire manufactures got better equipment fewer tires were out of round. A shaved tire will not give you the milage you want but they are smooth. The old saying, if you wanna dance you gotta pay the fiddler. I found Firestone to be the worst. A lot of it could be the luck of the draw. Sometimes you can put an out of round tire from the front (if it is on coil springs) and put it on the back if it is leaf springs and the problem will go away if the tire from the back is not out of round. We can go to the Moon but don't ask us to make a simple thing like perfectly round tires.