1989 240sx KAE stock Bizzare Drivetrain Shake

[xs04298]

While driving the car, and reaching 15mph the car will do a little shake, wether it be in first, second, or 3rd gear, just a little budududud, but this morning i had to go through a 15mph school zone, in 2nd gear, i slow down around 17 mph i start hearing this thudthudhtuh(about the pace of a heartbeat, sounds like a rubber hammer hitting solid medal) and keeps doing it untill i drop my speed to about 12,13, so i bring it back up to 15 in 3rd gear, same thing, let it coast in neutral, same thing, engage thet clutch in gear and in neutral, same thing...so whenever i pass 15mph it does this dumdumdudumdumdumdum shake, shakes enough i can see the shifter bouncing around, also i can feel it, and it feels and sounds like its right under me or behind me, but that may just be an asumption...

No other symptoms, no whine, doesnt shake at idle or at speed, even highway speed, i checked the transmission mount, crossmember, drive shaft bolts everything is tight, i'm really not sure where to turn next

hayllpp!

Thanks,

brandon

[180fan]

checked that bearing at the middle of the driveshaft yet?

[xs04298]

Nooo I hadn't, but i just checked, and all the rubber appears to be torn and dry rotted, i live in a dirt road, is it possible dirt can get in there and burn that up? I mean that would make sense, since its the only part that moves the same speed no matter what gear at a certain MPH...

..Wonder how much of a charm that is to change out :-\

[180fan]

Yes, dirt + rot + age = bad mix for something that's always moving. I've got to get around to switching mine out as well unless I opt for a lightweight driveshaft. But it doesn't look too bad to change out.