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front tires . does this look correct?


macattack

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looks like a stud piloted wheel on some steel wheel studs, or a float on some shorter studs for 8.25"aluminum wheels. theres not much you can change to straighten that up if you still have your bounce, maybe jack up the front axle and spin it to make sure you dont have a very rare bent hub or wheel.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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thanks guys. yah still trying to isolate that wobble. happens at around 35-40 and after that fine. the truck has an ht740rs allison trans. it seems that just before it shifts into 4th is where the wobble begins. after it shifts everything seems fine. i checked the trans filters for debris and found nothing. oil looks brand new. the wobble also shows up when coasting back from hiway speeds. if i let it coast downhill with no acceleration it begins to wobble from 35-40?? once its passed it rides great.

changed and checked alot of things still hunting.

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Hmm, seems to be the wobble happens at a time when there is no load on the driveline then, right before the shift from 3 to 4 if its like some I have driven it kindof lags and coasts a little the power pulls back, then as you said when you coast it wobbles, if you stay on the throttle hard thru the shift and that speed does it still wobble? if you force a downshift early and let the rpm stay high to keep torqe on the driveline when slowing down does it still wobble?

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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thanks 84superdog. this wobble thing has got me. i will explain it a little better.

accelerating up to 35 mph everything is fine. between 35-40 a wobble begins and lasts for only a very short time. it does seem to be worse rite before the final shift from 3rd to 4th. once in 4th everything is fine. almost feels like the driveshaft is whipping. if that makes sense.

driving the truck my steering wheel does not shake or vibrate. you can steer like its new.

when i go downhill in gear and let the truck coast the wobble shows up and then dissappears once i get to 35mph. wobble lasts for about 5mph.

it actually feels like someone is rocking the cab between 35-40mph. if i stay hard on the throttle wobble is still there but not as bad.

i thought it may be my transverse rod (one from the rear axle to the frame), but it seems fine. i had much the same wobble issue on my other truck (international) and my transverse rod was shot, but this one seems to be fine.

the truck has the large 425 in front and 12r22.5 in the rears. i have only 90lbs in the rears maybe i should up them to 110 or so??

i should also mention that this truck is equipped with air throttle. found this out when my modulator valve screwed up.

the throttle is controlled by a small motor connected to the linkage on the pump. also since it is air operated, the mod valve is a pneumatic type. anyway may have something to do with the way it shifts?? just a thought.

thanks for your expertise.

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I would keep the tires aired up to within 5-10psi of the spec on the sidewall, under inflated tires break belts and then blow out when they get hot and I would bet you are not riding around empty all the time. I dont think its a tire vibration sounds like its driveline related to me, especially if it is not as bad if you power thru the shift keeoing the driveline loaded as much as possible keeps the slack out, I would check the driveline and drive axle suspension mounts one more time, you seem to have an issue, whether its a carrier bearing or u-joint or torqe arm I dont know but a tire out of balance or out of round will be in sync with road speed and applying more load to the driveline wont make it any better so Im betting on a driveline issue, pay close attention to the carrier bearings and u joints a u joint will make a shutter when there is driveline slack.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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thanks again. i will put more air in the rears and see what happens. i may be able to get the rear end lifted up this weekend. i am gonna try to run it at the issue speed with the rears up to see what the heck is going on. being in a smaller town a guy does not always have quick access to the right equipment.

thanks

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Well good luck, I hate to say it but jacking it up and running the tires at speed won't show you anything, the tires will wobble all over the place and bounce like crazy in the air the only was to run one at speed like that is on rollers like a dyno.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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