[lakailimited06]

made a thread about this couple months back and ive searched and found similar but i cant find a solution to this...

when im driving 0-45mph going through 1st 2nd 3rd and 4th all is well no vibes and its smooth, once i hit overdrive in 45mph+ i get a growling sound and vibrations coming from the the floorboard i believe...also its only when im giving it steady gas or accelerating from 45+ in overdrive, once i take my foot off the gas at any speed the sound and vibes go away...

ive had this before i swapped out the cv driveshaft for my double/double cardan and ive taken my new one out just to make sure, and i still have the same sound and vibes with it out..i thought maybe the weight of the new shaft was the cause but if this sound and the vibes were there before hand than what gives?

any ideas?

[lakailimited06]

no idears?

[keith20mm]

Check the transmission tail shaft extension bearing/bushing. Under the vehicle, push up, pull down, push left, push right, where the driveshaft attaches to the transmission output shaft.

More than about 0.020" slop in the bearing/bushing support will produce a vibration as you describe.

Also, depending on model, there may be a grunge buildup inside the spline that mates to the output shaft. This can cause an out-of-balance condition.

Additionally, inspect the driveshaft for missing weights. They are spot welded to the driveshaft tube, and a missing weight will show as a rectangle outline with a small center weld, the outline produced will be where the weight used to be. I'd not expect a missing weight unless you've grounded out on the driveshaft.

Bent driveshaft might also produce this vibration.

[JoshuaDHarp]

my wifes 01 wj does this too. Only it's right at 60. Doesn't shake with gas just when I let off.

I need to check motor mounts and everything underneath but I don't think it's the engine, just because it only does it at 60.

[tirus89]

I got the same thing in my ZJ. I thought it was attributed to the transfer case. But you have the 242 and I the 249, so I dont think thats the culprit anymore.

[jeepdaddy2000]

I to have the same problem in my 97 5.2. While I haven't been able to check it yet, I'm suspecting either a slipping band or a problem with the locking TQ.

[lakailimited06]

found this.......

[lakailimited06]

alright well today i had some time to play around with the jeep.

i shut overdrive off, and went 50-60mph while in 4th gear, and no vibes or humming/growling sound..

so i took the front driveshaft out, and the vibrations seemed to have diminished when in overdrive...however the sound is still there....

im thinking when the driveshaft is in, its vibrating from the sound given off from somewhere within the tranny or the transfer case...either that or maybe the driveshaft isnt balanced correctly?

is it hard to balance such a large heavy driveshaft? its a double cardan on both pinion and TC side from Carolina Driveline..any you other guys with a Carolina u joint driveshaft get this same thing? this is getting real annoying

[CrazyDrivinJoe]

100 bucks to have it retubed cheaper to balance... it could just be your transmission overdrive gear. my dads dodge ram has had the overdrive gear bearing blow twice and it could be that there both mopar unsure which tranny he has and if its the same just a thought

[lakailimited06]

thanks man...i think my first plan is im going to take my driveshaft to a local shop and see if its balanced and if it isnt have them do it..if that doesnt work, then im going to take it to a mechanic because i know notihng abuot trannys and i wuoldn't want ot dive into mine just yet..

[skain8]

Since the problem was there with the old driveshaft, and there without any driveshaft at all, I would suspect that it is not driveshaft related. I would take to mechanic to diagnose, which should cost the same, likely less, than a shaft rebalance.