Driveshaft Question

[91toyota4x4]

I think my rear driveshaft isnt slipping as much as it should. When the rear suspension compresses it compresses the back shaft a little and then it stops and pushes the front piece forward which pushed the t-case forward and then the trans and motor i guess. I dont think that should be happening. I had my GF bounce up and down in the bed and I layed under there and watched it all happen. When driving and hitting big bumps i can see the shifter going forward and back in the cab. It's been doing it a little for a while but no shocks has made the problem alot more obvious.

I havent greased it in forever though. But it seems like the thing is compressing some and then stopping for some reason. Could it be too much grease?

I dont have a grease gun with me but I do have some grease (I'm in Melbourne) so can I take the shaft and pull it totally apart and clean and re-grease it?

I dont know crap about this kind of thing.

[twotontoy]

It shouldn't compress fully even if it's sitting on the bump stops. Something must be binding it up, and I guess too much grease could do that. I would take it off and look at it. Just remember to mark your flanges and shaft before you take it off the truck, same thing with the slip yoke, so everything goes back together exactly the way it came off.
When it's back on the truck and you put grease in the slip yoke, watch it closely, and stop filling it as soon as you see it start to move (seperate).

[91toyota4x4]

What's the slip yoke? The part were it slides into itself? I guess I'll just take it off tonight or tomorrow and try to figure it out.

This is a 2 piece shaft and the problem is comming from the rear half of it.

It isn't like a hard bottom out either. Hard to explain but it isnt like a metal on metal bang. There is a slight clunky noise, or thud instead. I dont really get it though I just lifted the thing 3 inches, though it did the same thing before, now the shaft is streched further.

[85sfarunner]

Wouldn't excess grease escape through the splines?

Sometimes I notice a clunking noise driving over potholes at slow speed. Never really thought about it much :rolleyes: . My truck makes lots of weird noises though :D .

[twotontoy]

Yes, that's where it slides in and out. If it's loaded with grease you won't hear a metal on metal noise. I know what your talking about, I have the same kind of shaft on my truck.
If your truck is lifted 3" it doesn't make any sense that the slip yoke could be bottoming out.
Only thing I can suggest is to pull the shaft and seperate the rear part to have a look inside. It sounds like something is preventing the slip joint from compressing as far as it should.

[91toyota4x4]

I pulled it apart and it goes in and out. The thing is that as it going in, or out there is like a buildup of air pressure behind the grease that makes it pretty hard to extend or compress and then it gives all the sudden. Is that normal?

I'm gonna go fool with it some more, came in here to look at the FSM online :rolleyes:

[85sfarunner]

Yeah it's normal the grease forms a seal in the splines which can cause a suction effect.

I might check my engine and tranny mounts to see if they need to be snugged down.

[91toyota4x4]

Umm yeah so it turns out I'm just an idiot and dont grease my stuff.

I put some grease on the splines and now it seems to be fine :mad:

I am not smart.

I wouldnt be suprised if my tranny/engine mounts are jacked up though because it has been getting jacked around by the shaft for a while :xsmash:

[91toyota4x4]

I think it's the Ujoint at the diff thats the problem. Yesterday when I had it apart that ujoint was smooth in one direction but felt like ass in the other, pretty rough and a little hard to rotate. Now I greased it today and when I start going something is making a little clanky-clunk comming from what sounds like right under or behind the driver, I bet it's that Ujoint.

Brian how hard was it to change that out? Did you need any special tools?

[85sfarunner]

It's not hard and no special tools are necessary with the exception of a BFH :) .

[91toyota4x4]

Well I replaced the u joint but it didnt really do much. It was going bad though and it did fix the clank I had at takeoff and calmed a little of the vibes.

Something is still forcing my tranny/trans forward when I hit bumps though.