Hello all and happy new year! Ok i have a 98 12 valve 4x4 with the nv4500. I have been noticing and vibration or rattle coming from the drivetrain when accelerating while loading the motor while in 3rd from around 25-30mph, (around 1,350-1,600 rpm). I thought it might be a u-joint but I have checked and all are tight. I did notice some slop, or side to side and up and down play on the top of the rear driveshaft coming out of the transfer case, output shaft/bearing? Has anyone else reported this also with a 5 speed or an auto? I am not exactly sure but is there any other possibilities as far as maybe the actual transmission? Any help would be appreciated as I have 83,500 mi on my truck and I don't feel like giveing the ******* money to investigate for non warranty work. Thanks guys!

Bill D.

 

Is there a mid-ship bearing on your truck? If its worn it may present similiar symtoms. I observed what I thopught was a u-joint failing turned out it was the mid-ship, wrty service, but for some reason they had to replace the whole driveshaft assembly about $1800 worth and after only 35K.

 

how many miles?? and when you inspect thr joints are you out of gear??
and check the yoke (s) real carefull...infact u joints ..please rechec them re carefull ..LOOK and FEEL ant slop is not admisable

 

I have 83,500 miles on my truck. I checked the u joints. There is no slop at all in the joints. I even went so far as to pry on the yokes with a bar and there was nothing. My truck is a regular cab 8 ft. bed so there is no mid bearing. any other ideas?

Bill D.

 

ok this is going to sound stupid but bear with me...will it give this vibration with a nois?? and will it do it at fast idle in nutral 1st clitch in then out???

 

There is a very small change in pitch of sound when i let the clutch in and out in neutral, but it mostly sounds like the gears running in the tranny when the clutch is released. The sound i am describing when the motor is lugged/loaded in 3rd gear is way more harsh, as it vibrates the whole truck but only for maybe 2-5 sec. untill i get out of that rpm range. after that it drives nice.

 

if you rev to 1700 rpm and hold her there will it in anyway duplicate it.
and I think someone all ready asked you about the carrier bng??

 

nope . and it is a regular cab so no carrier bearing

 

Is it possable the driveshaft or something could be out of balance? wouldnt that make a bad vibration mainly at certin rpms?
I know tires do that.

 

Oops on my first post, regular cab.
Check the motor and transmission mounts for looseness or cracking.

 

well were diging deep know....the only 2 other ez things ..loose/broken eng mts.or busted loose shackles?...somthing that will let the axle walk around ????then this is a mabe dose, your transfer case have a chain in it??
and dose it do it in just 3 rd gear?(is that what you said)??

 

basically it does it when i am loading the motor between those rpm ranges. it is slightly noticable in 2nd, bad in 3rd, and real bad in 4th and so on in 5th. the faster the drivetrain spins the worse the rattle. the mounts are all tight and in good shape. the slop i am describing is actually on the splined yoke coming out of the transfer case. Seems to me like the output shaft on the transfer case has the play. I can't tell if it is in the spline or in the shaft or bearings. I was wondering if anyone else has reported this? I am clueless on where to start and i really don't want to pay the dealer. that might cost me more than the truck is worth.

Bill D.

 

My sons 94 3500 does the same thing, drives me crazy.

 

welll.........it would seem a yoke bng. problem would be felt in all gears,so-dose it do it at all in high??????/
if not i would suspect cluster gear bng. problem

 

check you driveshaft for dents or twist i had a very small dent on my 92' bad vibes aroun 65-70mph it evently ruined the tranny. igot the shaft re-tubed problem gone.

jed