I took the Trekker out for a spin this evening after getting some things back together and its got a nasty drive line vibration, at first I thought it might be tire / wheel related but I dont think it is now. At 45mph its pretty bad, when I push in the clutch / throw it into neurtral its dies down. Does this sound like a drive shaft issue? Ill be 100% honest, Ive not greased anything yet nor have I really inspected things in depth like the drive shaft and U joints. Last week when I drove the beast home I thought the vibration was all tire related, they were really really low on pressure and were installed years back but have no miles on them, I just figured it was flat spots but now Im really not so sure! Im going to check my drive shaft for slop, hopefully its nothing major but somthing feels / sounds out of whack in the rear end of the beast! Any ideas would be a help! ~Matt

 

Sounds like a U-joint going south to me. Thats exactly how the u-joint on my 98 tacoma acted when it was going out. Started vibrating, the worst at 45ish, then the range of vibration got bigger, than it began to clunk when shifting, then I replaced it.

 

I've been lurking here for a while, you get to be my first post =)

It seems unlikely that it would be a u-joint issue if it dies down when you depress the clutch, as the driveline continues to turn as long as the vehicle is in motion. However, I had a driveline behave similarly on my '79, the vibration lessened but didn't quit completely when the driveline was not under engine load.

For me, this was because the bolts that hold the driveline to the transfer case were coming loose, causing the plate on the driveline to separate slightly from that on the transfer case under load, and cause vibration. If I were you, I would get under there, and make sure they are all still in place and snug at both the transfer case and rear end. Also, if they were loose, a drop of locktite may do you some good, for me I had 3 bolts drop out on the road after I had already tightened them. due to clearance issues, these bolts are a slightly abnormal stud to head size configuration, so finding replacements can be a real bitch.

U joints could be possible however. If this is the case, they would have to be in BAD shape, with all the needle bearings inside basically gone completely to allow the driveline that much slop room. One way or the other, if you haven't replaced them on this truck, you probably should. They can bea pain to remove, but u-joints are one of the most common points of failure on this vehicle.

Good luck!

 

Pumpkin, it was actually the big nut behind the plate that the shaft bolts to on the rear diff input shaft! I dropped the drive shaft and re-torqued the nut to 90ftlbs and was good to go! I dropped the front too and it was a little loose too! I think a lot of the existing vibration is just from the 10 year old Continental tires, they have very very few miles on them but are hard and I think they have flat spots from sitting for long periods of time, the truck hasnt seen the highway in a few years, just back roads....

 

Glad to hear you got it figured out. Did you look into the u-joints while you were under there?

 

Why can't all newbs posts be helpful like this??? Welcome to the board Pumpkinyota!

 

Thanks, glad to be here =)

 

I'am having the same problem with my 81 yota, but it has a new drive line. At lower rpm's mine really vibrates and it smoths out with higher rpm's and speed. I've had a few people say that it might be the flywheel though.