still vibrations in overdrive!?

[lakailimited06]

i would check the pinion angle i have no idea what it should be or how to really change it...i dont know if i can really change it that much with just the lower arms, the a arm isnt adjustable..

[XJtheXtremeJeep]

i would bet that is the cause of your vibes.. thats what mine was and i had to cut/reweld perches but its a little more expensive with coils... unless you have full adjustable control arms.... the yoke on the axle and the drive shaft should make a straight line, no bend in it at that u joint at all

[lakailimited06]

i have rear lower adjustables i will see what i can do the next sunny day..

[XJtheXtremeJeep]

yeah i would def start with that especially since it doesnt do it when your just coasting

[lakailimited06]

well, got it back today for the second trip to the mechanic with the jk wheels/tires on...mech now says without the MT's he can tell its definitely coming from the rear end and that its shot...

he said im gonna need a whole new rear end rebuilt and put in for $1350.00

im still not sure if this is 100% whats wrong im gonna pop the diff cover when i get a chance and see if theres anything in it..

either way im not paying that much money for a crappy D35 to be put back in if anything ill get a junker one and use that since money is tight or maybe bite the bullet and swap a 44a but then ill have to regear...im in a pickle right now lol

thoughts?

[lakailimited06]

ok so...thought something in the rear diff was shot causing my vibrations...had the 30/35 regeared to 4.10s and i still have the same vibrations..

so far besides all of the above ive recently:

-had the driveshaft balanced and new joints put in (again)
-dropped the tranny pan twice, once to check for anything in it, 2nd to put a drain plug on it
-played with my rear pinion angle by adjusting my lower arms..Iron Rock says put them at 18 5/8" which i did, had the same vibes...lowered them to ~18" which is just slightly longer than stock arms and no difference still had same vibes...

i dont think its the pinion angle because after playing with it for 2 days the sound hasnt even changed at all..

the guy who did the gears said my slip yoke might be maxed out and i need an SYE..i dont believe this because theres guys running 6.5" lift with my same rear shaft...

plus the rear driveshaft is alot longer than that of a TJ etc and SYE's arent too commonly done on grand cherokees..

again im only at 3" in front ~4" in rear...im stumped..

could it be a tranny problem? im just tying to think of where my next paychecks are going towards..

also the guy who did the work on the gears said he drove in 4 wheel with the rear shaft removed and he said the vibes werent there (hence the reason to replace u joints again and have it balanced)

TIA

[XJtheXtremeJeep]

dude im tellin ya take a look at pinion angle.... same stuff mine was doing

[lakailimited06]

pinion angle seemed fine...i measure 6-7* on the pinion and 6-7* on the TC output shaft...if it was the pinion angle i think i would have at least heard/felt a change in the way the vibes occured..i tried my short arms at 3 different lengths and on all 3 the vibes occured same exact time...