Okay so here is the issue. My truck 91 sr5 4x4 with a V6 started marking a weird vibration sounding noise coming from the drivetrain. So here are the symptoms.

1. Truck has no issue in 1,2 or 3rd gear.
2. 4th and 5th get this loud whining and sounds like it is vibrating more then normal.
3. The transmission makes only a quite whine when it is accelerating but make a loud metal on metal rubbing noise in the middle to rear part of the drivetrain between accelerating and releasing the gas pedal.
4. If i put the transmission into neutral all the noise gears completely away.

There is a support bearing just to the rear of the transmission that needs to be replaced as it has at least 1.5"-2" of place. So this might be the cause but seeing as the whole rear driveshaft keeps spinning with the axles shifting it out of gear shouldn't get rid of the sound it that was the problem. I have added a photo of the bearing i am speaking of its in fron the the three grease nipples on the driveshaft.

Well if i have to i'll be taking into a mechanic to get the transmission check out and if it is the transmission then i get to buy a new to me diesel jetta . But the truck is getting the 2lt from a 85 swapped into it. I already have all the parts from a old wreck 85 pickup so it would be nice to use the truck as a project truck.

Any help is nice.

Thanks.

 

If that drive shaft bearing has that much play in it, then that would be a good place to start. A bad bearing can make all kinds of noises, so replace it and go from there.

 

had a friend who had his carrier bearing go out. gernaded his driveline and $500 later he got a new one. the funny thing is about a year ago they were only like $35 at autozone and now they are over $100
grease all of the u joints and the splines on the shaft.

 

Thanks for the responses it's always nice to check with others who has been or seen the same issues. Going to try and get replacement parts this week/weekend. Hopefully it's just a simple center bearing. Grave highways sure can do a number to trucks.