for the last few months it seems that while i drive it feels like i have a tire thats not round. It only does it every now and again and it will do it and stop and a little bit later it will do it again. Only last a few seconds every time it does it and probably no more than 30 seconds. I've changed tires so i know its not my tires. I've lowered the tbars all the way but it feels like its in the ass of the truck. I have pulled the overloads but i don't remember if it did this before i pulled them or not. I just installed 2" lowering shackles but i just put those guys on friday.
diagnose my problem?
- Thread starter quick6.6
- Start date
check for wheel bearing play and i have none. pulled the rear shocks and they still have some spring in them. Checked rear ujoint and its solid. Checked front u joints and both have a little play in them. I will replace them but could that be my problem? i'm running out of things to check.
Could be the lowering shackles, they change the driveshaft angle and cause it vibrate at certain loads.
thought of something else to check. i crawled back under and pushed up on the driveshaft around the tcase and it clunked. played with it some more and it moves up and down and thats probably what i've been feeling. is the shaft keyed into the tcase? i'm going to pull it and check it.
check for a broken or a loose bolt in the bell houseing/tcase or any thing like that i had some broken stuff under my truck once and every time i got to 40+ the trans would shack like heck
no more or less when i'm going straight..i do get a sudden slingshot effect when i go around some turns..like the truck just bolts to the direction i'm turning but mostly higher speed turns like 50 but thats once a blue moon. whats the problem if it bumps when turning? i feel it in my seat if it helps when i get my bumping going straight.
I had a UPS truck that would "slingshot" around on a turn. I'd turn the wheel and it would start to turn then all of a sudden without me turning the wheel any further the truck would really turn hard. Took 2 techs to figure out that the gear box was being held on by one bolt with about 4 turns left 
Just a thought.
Just a thought.
I would jack up the front end an check the hub assemblies and the ball joints, those hubs go out often
i checked everything on it and everything looked good. i went to the drag strip again on my old tires and i didn't really notice the problem anymore..i think its my new tires....i thought it happened with my old ones to but i guess not...i'll have them balanced.