Shaking at 45 to 60

[msb71]

Ok , fellas got one for ya,
Just recently my truck has started shaking in the front end or somewhere else, the problem starts at 35 mph to 60 mph , skakes or hops harder when you gas it then let off at highway speed.
i took it in and had the tires rotated and balanced thinking I may a tire out of round or something , but problem is still there, possible scenarios:

Shocks have 50K on them and have had a hard life ( has quad front suspension)
Rancho 5000's.
The guy at the tire place suggested it may be a drivetrain problem as he checked everything.
The u-joints are tight and look good as does carrier bearing.
I know for a fact my Ring and pinion is going bad , it clunks real hard when I shift to reverse.
I f anyone has any ideas what this may be, please this is very annoying , I live in the city so 45 is a driving speed around here , driving nuts.

 

[Lost]

I would not rule out the u jionts . A dry cup can do what u described.

 

[95F350XL]

Ill 2nd u joint. Even tight they can give probs. I know at work we did this once, pulled the rear shaft and put truck in 4x4 so just the front shaft was drivin the truck. You could try that. Also that you have the shift kit the u joints are gettin banged when it shifts.

 

[Skandocious]

Ill 2nd u joint. Even tight they can give probs. I know at work we did this once, pulled the rear shaft and put truck in 4x4 so just the front shaft was drivin the truck. You could try that. Also that you have the shift kit the u joints are gettin banged when it shifts.

Not possible on these trucks. He'd have to at least leave the front section of his rear shaft ON the truck or else it would start spewing ATF out the rear housing on the tcase.

Also -- Mike, just because it clunks into reverse doesnt mean your ring and pinion are bad. Mine are brand new and mine does it too. I believe it's more involved with the trans/tcase. My old ring and pinion did it and they dont have a single mark on them, look brand new. I'd rule that out as possibility.

If I were you, I'd remove the rear driveshaft and see if any of the ujoints bind when you try to rotate them in different directions. Often times you can't tell when the ujoint is bad if you've still got it on the truck.

 

[msb71]

OK, I'll check the u-joints out then , they aren't that hard to replace. Just recently I replaced the ones on my Mother-in-law's Crown Vic , you want to talk about no ground clearance , was a pain to get the shaft out.
I'll give it a try then , thanks for the quick reply's , if anyone has any other ideas , feel free to chime in.

 

[95F350XL]

Chris they do make plugs that go into the tailshaft to seal it up. How did you ck them? Using a prybar and seeing if they moved?