Locker Noises

[stockk5]

Alright i just put a new axle in my truck with a detriot in it. When i am driving now and im off the gas i feel a slight vibration throughout the floor of the truck. My ujoints are all new, my driveshaft angles are perfect and dead on so i dont think it could be that. The noise tends to come more when im going straight down the road right after i let off the gas. Anyone have an idea what could cause this or is it just how the detriot tends to work?

 

[trailblazr81]

Hmm, mine didnt vibrate, but I couldnt tell or didnt bother with the lift, n big tires. I could definately feal it when I let off the gas or got on the gas. Is it a constant steady vibration when you coast or just for a second or 2?

 

[MTMike]

Could the new axle have changed the driveline angles? Maybe the pinion is tilted up a degree or 2 more in the new axle vs. the old one and the u-joints are out of sync.

 

[stockk5]

well the driveline is dead even now. the spring perches were welded on so the driveshaft's rear u joint is perfectly even up to the rear yoke which isnt at a bad angle at all.. no binding or anything.. it seems to only be for a few seconds after i let off the gas. then goes away....

 

[MTMike]

If the perches were welded on, and angled the pinion (relative to the parallell ground) differently than the old axle, then the pinion-to-U-joint angle may be different than the TCase-to-U-joint angle, which would cause a vibration.

Driveline Geometry explained: http://4xshaft.com/techinfo.html

 

[87BrnRsd]

Alright i just put a new axle in my truck with a detriot in it. When i am driving now and im off the gas i feel a slight vibration throughout the floor of the truck. My ujoints are all new, my driveshaft angles are perfect and dead on so i dont think it could be that. The noise tends to come more when im going straight down the road right after i let off the gas. Anyone have an idea what could cause this or is it just how the detriot tends to work?

If you fill out your user profile, it may be easier for us to help you. Anyways, after installing a new rearend with a detroit, and a lift in mine ( I saw you also did a lift at the same time), I had the same vibration only when I let off the gas. If you have a np 208 t-case, then its all about the angles. I have an np 208 and the only way to get the noise to go away (the noise comes from the slip yoke in the t-case being at a bad angle and kind of moving around in there), was to get a cv shaft for the rear made. If you have a 208, then I bet that is what the problem is.
-Harrison

 

[badfish4tail]

Alright i just put a new axle in my truck with a detriot in it. When i am driving now and im off the gas i feel a slight vibration throughout the floor of the truck. My ujoints are all new, my driveshaft angles are perfect and dead on so i dont think it could be that. The noise tends to come more when im going straight down the road right after i let off the gas. Anyone have an idea what could cause this or is it just how the detriot tends to work?

Wow, I am having the same prob. I just swaped out my 10blt for a 14ff w/detroit and when i get speed up to about 40-45mph and let of the gas to coast i hear and feel the vibration. I also replaced my u-joints. I will have to recheck my angles. It does sound like it could be my pinion vibrating against the ring

 

[badfish4tail]

Just looked under my rig and my pumpkin looks like this, but i dont have the CV joint at the top, i have a slide in

 

[lrazer]

that would cause it
the ujoint angles need to cancel each other out
and you don't want a ujoint to run at 0* should have some angle to it
ideal is 1-2* but we know thats not gonna happen on a lifted truck

 

[stockk5]

here are pics of my angles... what will happen if i keep driving w/ the vibes?

 

[stockk5]

here are pics of my angles... what will happen if i keep driving w/ the vibes?

 

[MTMike]

Yup, your problem is a driveline angle mismatch. Your pinion is angled up so your pinion ujoint angle is ~0* and your transfer case u-joint angle is at at least 5.

You either need to rotate your pinion down so the 2 angles match, or get a CV shaft.

What will happen is you will be annoyed and it could lead to premature u-joint failure.

Mike

 

[trailblazr81]

You will eat U-Joints. I got a 1350 CV shaft and no vibes and no busted u joints.

 

[Beast388]

When I installed the 14BFF inmy Burb I had the same problem. I had a vibration at highway speeds. I purchased a $10 angle finder from Home Depot and measured the two angles. I ended up putting a 4* shim in there to correct the problem.....no more vibration.

 

[Beast388]

Looking closer at your pictures, I bet that once you angle the pinion down far enough, your d-shaft will be too short.

Hard to say until you measure and move it.

 

[87BrnRsd]

here are pics of my angles... what will happen if i keep driving w/ the vibes?

That angle at the t-case end looks bad. Jack the rear end up (block the front tires of course), and have someone get on the gas while you look and listen under the truck. I bet its comming from the t-case and not the diff. The easiest way to solve your problem would be to get a cv shaft made. It fixed mine. Oh, and left unattended, it will eat u-joints, and can kill the seal in the tailshaft of the 208. That will make you lose a lot of tranny fluid. Unnoticed, it could kill your t-case.
-Harrions

 

[trailblazr81]

I like the 3 exhaust clamps within like 12"s.

Also the old bare V-8 out in the yard...in the snow!!

 

[stockk5]

I like the 3 exhaust clamps within like 12"s.

Also the old bare V-8 out in the yard...in the snow!!

haha yeah.. i didnt do the exhaust.. however that is an old 318 i am scrapping... maybe the money from all my scrap metal can get me a new cv driveshaft....

 

[trailblazr81]

Check out Denny's Driveshaft and High angle driveline.

 

[lrazer]

it almost looks like your angle at the diff is slightly above 0*
could probally use a slight downward angle to that and of course a cv joint at the tcase end