High Freq. rumble

[SteveMc]

My 1987 Suburban has 220 k miles and has had a drive train high freq. rumble since I got it at 187 k. Have had all drive shaft rebuilt and balanced by local pros. That made a noticable differance. Now at 60 mph it starts to rumble and seems to be coming from rear. Putting trans in nutral and idling the eng. makes no differance.

The rear is a ten bolt limited spilt system that was rebuilt 80 k ago. Ive been thinking about pulling the axles and having them checked, but the freq of the vib seems faster than an axle turning unless they are both messed up I guess.

Would appreciate any thoughts or past experances.

SMc

[sidedump]

Check out what Randy's has to say.
http://www.diferentials.com/tech/yukoninst.pdf
This pdf should tell you what is going on in your diff.

[More Power]

Wheel bearing problems can produce these symptoms. Try gently rocking the steering wheel side to side at cruising speed (or whatever speed produces the most prominent sounds) to determine whether loading/unloading each side of the vehicle changes what you hear.

MP

[SteveMc]

Thanks for the tips. I'll be changing the diff. lube soon, so will also get a look inside the pot to see if anything looks amiss.

SteveMc