crazy sound under acceleration?

[knottyrich]

got a "whap whap whap" kind of sound when i gas her hard? like shaft is rubbing? maybe since lift ....rear shaft doesn't push into yoke far enough? i need new shaft but am i getting warm? just had u-joint replaced....already burned thru them? everything seems tight. of course i can't yank on t-case to see if its loose....f^&*%$$%ker weight 9000lbs. somthings going on down there. maybe drv shft balanced?
also got a grinding sound when i let off accelerator at like highway speeds?
i know kind of vauge questions..but any help is super cool! thnx
got a **** load of stuf for the rear suspension....keep ya posted on how it goes togther.
later knottyrich

 

[howdiy]

How is your pinon angle?

 

[Hogback Fabrication]

How much lift? And as mentioned, what does the pinion angle look like?

 

[knottyrich]

not real sure of angle , i put a 6" lift, nothing too extreme, is there a way to jack truck up and turn shaft by hand and see if its binding?
guess i could buy a angle guage? hold it on to the shaft?

 

[wasted wages]

6" lift with no driveshaft modifications.....

could be slip joint is maxed out front and rear,,,,,or the double cardan joint at the front of the transfer case is binding against the stops...may need to pull the front shaft and grind the stops down as a temp fix...

my experiance is with 6 " of lift you need to have the shafts lenghtened,,and the driveline pinion angles checked,,,and adjust with shims if needed..

hope this helps

 

[knottyrich]

frt drv shaft shouldn't be spinning when in 2wheel drv right. i did have the front lengthened 2" and "stops" ground a little. i'm thinking that the rear is not seated in the yoke far enough.....gonna get new shaft made with the same kind of slip part as the front...in the middle of shaft. i guess they call it slip yoke eliminator??