Rumbles when I let off gas

[ccso503]

OK new U-joints installed and same outcome. The drive shaft appears to have the weights still attached and dosent look like it has one missing. This has only done the vibration thing in the last few days and before that it was fine.

The transfer case is leaking around the output shafts, but still registers fluid. I will be droppin gthis in an hour or so but dont know what to look for inside.

Im going to replace the seals and clean it up when its down though.

 

[nad]

The seal that's leaking on the tailshaft could be the vibration problem. That means your slip yoke is wiggling around in the seal. That would be the next thing to replace and see if that fixes the problem.

 

[driney]

Inside the tail housing is a bushing that may be worn. It isn't very expensive so I would probably change it while I was at it.

 

[ccso503]

OK, I reinstalled the drive shaft the other day with th enew u-joints and had the same problem. I drove to the parts store and got some new seals, dropped the transfer case and installed them. Put it all back together and I had to go to town to get some otherthings today and the drive shaft rattled off the rear u joint.

So now I got smart and decided I had to spend some money and went to the junk yard and got a used shaft, took it to the drive shaft place nad nw they are makeing it about 3 inches longer because of the lift on the truck.

So now I inpatiently wait for it and will prob have to get it tommorrow instead of today but hopefully this will have corrected my problem for now.

What are some other things I should look at as far as the truck's drive train being stock and the added pressure of the lift and bigger tires? I downgraded to 35's already.

 

[nad]

How did the shop know exactly how much longer to make it without seeing it on the truck?


I think I fixed my problem by centering the joint on the pinion, somehow it wiggled itself to one side.

 

[ccso503]

My buddy has a shop in the town I live in, he picked the Blazer up on his rollback and took it for me. I was also told that you can measure from the 3rd member to the end of the transfer case, or add however much of the shaft is actually in the transfercase and add that to the overall length of the driveshaft.

It sounded clear as mud to me when he said it so im sure I confused it up a bit but I know I was somewhere in the area.

 

[nad]

That's why I've always been afraid to have a custom shaft made. Unless the truck gets towed to the shop to get it done properly, it's hard to know. And towing is expensive when you don't know someone

 

[ccso503]

yep, funny I offered to buy his gas and he said a six pack would be better, so I got him the beer for 5 bucks and the gas would have been at least 40? go figure.

 

[k2mslskier]

Sorry to Hijack but I'm having the same problem. 4" lift with 35's...but it's been this way for almost 2 years and the vibrations just started maybe a couple of weeks ago. It did this to me last summer as well after a good romp in the mud. Sprayed off the truck/wheels/underneath really well and it stopped.

I sprayed it again yesterday really well and greased everything today making sure everything was tight. Still doing it. I'm stumped.

 

[ccso503]

Well at least I have a longer shaft now. I still have the vibration as well. It is def coming from the 3rd member. I will be looking at it hopefully this weekend to check on it.

Is there a seal or bearing that can be changed out on the driveshaft side of it?

 

[obijuan]

getting a new driveshaft doesnt necessarily adress your ujoint angles. what are they?

if by third member you mean the pinion yes theres bearings inside the pinion snout of your rear axle. if theres any play up and down or the rotation of the pinion feels gritty the bearings ought to be replaced.

 

[WJACKSON11X]

check the pinion bearings for play. This was my case, so I just decided to put in a 14bff instead of changing pinion bearing. Worked out better anyway,stopped the vibes and I got a kicka$$ rearend.

 

[k2mslskier]

Hijack again....replaced U-joints today....smooth as silk. The rear was so bad it wouldn't even turn when I took the driveshaft out. Replaced with Spicer greasable ones.

Hijack over.

 

[obijuan]

yikes man! glad thats taken care of.