Vibration coming from rear axle???

[ScottsHZJ80]

G'day, I'd better introduce myself before just jumping in and asking questions. I have been lurking (mainly in the 80 section) for a few years. I run a '93 HZJ80 which is closer to a 70 series in terms of running gear than an 80. It is a 1HZ with 5 speed manual and part time 4wd so any questions I have about the trans and drive line are probably likely to be relevant to the 7x series as well as the 80.

Anyway, my problem is a vibration which appears to be coming from the rear of the truck. It is most noticable taking off from a standing start, and feels like really badly scalloped tires, but dissapears by the time I'm in 2nd at about 10 kph.

I replaced the rear drive shaft because the old one had a bit of slop in the slip yoke splines, which is to be expected after 390 000 km, which made a huge difference and stopped most of the vibration. Now I have a small vibration at about 80 kmh (50mph) that I am still trying to sort out.

What I am wondering now is whether the vibration in the tail shaft could have caused any damage to the diff. I have no idea what symptoms a failing diff displays as the only ones I have had let go before have done so in a very spectacular fashion on the trail ie BANG!!!

Any help would be appreciated.

 

[Ron R]

Not very likely but have you checked the rear wheels in regard to balance?

I don't think you've done anything to the reard diff. The bearings are very sturdy and the vibration is in the radial way.

What you can check is or there is no play in the joints and make shure the yokes are in line. As a last resort you can get the driveshaft balanced. This is not that expensive and normally is carried out when the spider and bearings are replaced.

 

[ScottsHZJ80]

Ron, thanks for your thoughts.

It is about time for a tire rotation so I'll swap front to back to try to eliminate any tire balance issues. The uni joints felt OK when I put the shaft in the other day but I may look at replacing them next weekend. IIRC they are about $25 each so that might be a nice cheap fix.

If that doesn't help I guess I need to look at checking the balance of the shaft. Again, thanks for your help.

Scott

 

[knorrena]

Have a look at the pinion nut. Toyota pinion nuts sometimes work themselves loose after a while.

Karl