Hi, I have a headache on my hands, I cannot get the driveshaft on my 90 suburban to stop vibrating.  It is a one piece assembly, I already replaced both u joints, but the front yoke that slips onto the splines on the tranny seems to have a considerable amount of play.  With the driveshaft off it also seems that the splined shaft in the tranny also has some slop.  The play of the front yoke on the splined shaft appears to be wear related, but the sloppy shaft in the tranny is a mystery.  The tranny has 1000 miles on a rebuilt, but what supports the yoke when slipped on the shaft is an unknown to me.  How much is normal and would replacing the front yoke with a new one help?  I was already thinking of replacing the front yoke but the slop on the shaft has me puzzled.  Your experiences and knowledge,like always are appreciated.

..oh.

I thought your problem would be,"..and I can't get my wife out of the damn thing."

I don't know nothing about cars.

he he no problems in that dept.

You may held off on replacing to joints to long.
Even if so it's not a big deal to fix it will just take time to take it all down.
As long as the splines hpld look and see if you bushings have gone bad.

Sounds like a bearing problem to me, you stated it is a suburban so I'll asume it is 4x4 and rebuilding your tranny has nothing to do with the vibration it would be the transfer case.....

2wd, and I do not know if the bushing got replaced when she got rebuilt.  I have a dim memory of another 700 that I saw disassembled that had the rear shaft actually slip into another assembley.  She vibrates in drive and neutral at speeds over 55, but how can I confirm bad yoke or bad bushings?

was the driveshaft balanced?

The factory tack welded weights are still one her.  Has not been dinged nor did the u joints completely blow.  This truck could cruise at 80 with basicly road harshness only being felt.  Now she is not a bucking bronco but the center console does vibrate enough to make the change in the little utility trays "sing".  I am going to order the yoke from the dealer tommorrow and hopefully that will help.  If you had this problem in a chevy 1/2 ton 2wd with a one piece driveline, I would be really happy to know how you solved it.

If you had it rebuilt 1000 miles ago take it back. There should be no play in the splined piece in the tranny. There is a rear bearing that must have given, or moved in some manner if you have slop in that.
The splined shaft is what holds your drive shaft in place when you put it in the tranny. The outside is just a seal surface to keep the fluid in.

Its [b]normal[/b] for the output shaft of the transmission to have a limited amount of play when the driveshaft is [b]not[/b] installed...(the bushing in the tail housing is what supports it when the driveshaft is installed)
If there is no/very little play when the driveshaft is installed, then that part is fine.

If it [b]DOES[/b] have play with the driveshaft installed...Then the yoke, AND/OR bushing are bad (if the yoke is bad, the bushing should be replaced also)

If your front yoke has wear on it, and is "out of round",...then YES, it is bad, [b]the ouside of the part that slips into the transmission should be smoothe, and uniform all the way around[/b] (some "minor" wear is usually okay)

I was gonna say bad spark plug but after reading this it may not. BTW I don't knows cars or trucks either. All I know is when my car vibrates, which it does once every 6 months, it's because one of the valves is not running right due to a bad spark plug.