SaS Dana44 Crazy bad vibrations at 1+mph in 4wd

[snow junky]

I'm having un drivable vibrations in 4wd. Only on street. On dirt/snow it seems fine

In 4wd hubs unlocked I have no vibrations
This is all going in strait line. Turnings another story


I have a spooled Dana 44 in the front.

I can't figure out what's going on. Thanks for the help

 

[mxer]

I have a spooled Dana 44 in the front.

I can't figure out what's going on. Thanks for the help

Maybe look into what a spooled differential is, then try and figure out why you are having problems. You have cheaply locked front axle, of course you are going to have problems on the street.

 

[4eigner]

I'm having un drivable vibrations in 4wd. Only on street. On dirt/snow it seems fine

In 4wd hubs unlocked I have no vibrations
This is all going in strait line. Turnings another story


I have a spooled Dana 44 in the front.

I can't figure out what's going on. Thanks for the help

What gear ratio in the front and back diff?

Edit: signature states 5.29 F&R, is this the vehicle in question?

 

[4Running Daily]

What have you changed recently? Are you sure the gear ratios are the same?

 

[snow junky]

Maybe look into what a spooled differential is, then try and figure out why you are having problems. You have cheaply locked front axle, of course you are going to have problems on the street.

Notice how I said the vibrations are in a strait line......

 

[snow junky]

What have you changed recently? Are you sure the gear ratios are the same?

I changed the front driveshaft spline and yoke. But it seems fine and no vibrations when hubs are unlocked and tcase in 4wd

What gear ratio in the front and back diff?

Edit: signature states 5.29 F&R, is this the vehicle in question?

5.29 in rear 5.38 front because it's a Dana 44 they equal the same

 

[4eigner]

I changed the front driveshaft spline and yoke. But it seems fine and no vibrations when hubs are unlocked and tcase in 4wd






5.29 in rear 5.38 front because it's a Dana 44 they equal the same

I understand that the Dana is not a Toyota and uses different gears, but I'm under the impression that gear ratios need to be within .05 of each other to work properly on pavement. Have you ever had this setup working properly on pavement? If not, have you verified those ratios or were you just told?

 

[snow junky]

I understand that the Dana is not a Toyota and uses different gears, but I'm under the impression that gear ratios need to be within .05 of each other to work properly on pavement. Have you ever had this setup working properly on pavement? If not, have you verified those ratios or were you just told?

Everyone that does a SaS with a toy rear and Dana front gets 538

Yes when I first did install it was working in a strait line on pavement.


I'm leaning on it being because of the spool or maybe the tcase chain skipped a tooth.
I have no idea. About to mount a camera down there to see what's going on

 

[KidVermicious]

5.29 in rear 5.38 front because it's a Dana 44 they equal the same

I beg to differ, my good man . Ask [MENTION=62048]thardy[/MENTION] about the 5.38 in his front D44 and the trouble he had. Combine that with a spool that doesn't let the tires rotate against eachother, let alone against the rear driveshaft, and you've found your problem. It doesn't do it on dirt because the tires are allowed to slip smoothly on dirt. Put it on pavement and they can't slip, so they're scuffing and bouncing.

 

[D Farms]

even if your diffs were the same the small difference in tire size will make them do this as well, also dont use 4wd on pavement! maybe you should have stuck with ifs.

 

[thardy]

I beg to differ, my good man . Ask [MENTION=62048]thardy[/MENTION] about the 5.38 in his front D44 and the trouble he had. Combine that with a spool that doesn't let the tires rotate against eachother, let alone against the rear driveshaft, and you've found your problem. It doesn't do it on dirt because the tires are allowed to slip smoothly on dirt. Put it on pavement and they can't slip, so they're scuffing and bouncing.

This exactly. I had the same issue with mine. The slightly higher gears in the rear are pushing faster than the fronts can keep up. On dirt or rock this is fine, but on pavement they will bind against each other.

Theoretically they should be fine, but you are experiencing the exact problem I had, which has sense been eliminated with a Dana44 rear and 5.38s front and rear.

 

[thardy]

Notice how I said the vibrations are in a strait line......

You're right, a spool shouldn't cause a problem in a straight line and shouldn't cause the vibration you are feeling. As far as cheap locker, yes it is, and in the front can be a pain, but that is a discussion for a different thread. A lot of people love them. I will likely weld my rear in the near future.

 

[snow junky]

I beg to differ, my good man . Ask [MENTION=62048]thardy[/MENTION] about the 5.38 in his front D44 and the trouble he had. Combine that with a spool that doesn't let the tires rotate against eachother, let alone against the rear driveshaft, and you've found your problem. It doesn't do it on dirt because the tires are allowed to slip smoothly on dirt. Put it on pavement and they can't slip, so they're scuffing and bouncing.

This exactly. I had the same issue with mine. The slightly higher gears in the rear are pushing faster than the fronts can keep up. On dirt or rock this is fine, but on pavement they will bind against each other.



Theoretically they should be fine, but you are experiencing the exact problem I had, which has sense been eliminated with a Dana44 rear and 5.38s front and rear.

Yea this is the only thing that would make any sense to me.

When I was doing research everyone said that 1% would even be ok on the street. With every tire rotation the front is only going about 1in further then the rear
I would think it could easily slip one inch for the 110in circumference. But what do I know

Guess I'll start looking for a wide trac Dana 44 rear

 

[snow junky]

You're right, a spool shouldn't cause a problem in a straight line and shouldn't cause the vibration you are feeling. As far as cheap locker, yes it is, and in the front can be a pain, but that is a discussion for a different thread. A lot of people love them. I will likely weld my rear in the near future.

I like the spool in the front. I would never spool the rear unless I trailered it to the trail

I had a heep that was welded in the rear and I could feel it slip on a 45mph turn. Scary as hell.

 

[snivilous]

5.29 in rear 5.38 front because it's a Dana 44 they equal the same

Gearing is gearing, a different axle won't change the ratios at all because the ratios are solely a function of the pinion and ring.

Yea this is the only thing that would make any sense to me.

When I was doing research everyone said that 1% would even be ok on the street. With every tire rotation the front is only going about 1in further then the rear
I would think it could easily slip one inch for the 110in circumference. But what do I know

I've heard you can be within like .01 gearing change (4.10 vs 4.11) but have nothing to base that off of. 1 inch of 110 doesn't seem like much, but that's still 1" that has to slip, which when you factor in a high friction/traction surface that's a lot of force and binding going on.

 

[csp]

Is this recent, or better question, has it ever been drivable with this combination?

I'd tend to lean towards driveshaft angles if it hasn't ever been drivable. You're within 2% (not within 1%) on gear ratio differences, which is borderline.

This is the difference as a percentage of the smallest number of the two ratios. It isn't 4.11 minus 4.10 for example.

5.38-5.29= 0.09

0.09/5.29=0.017 or 1.7%.

 

[snow junky]

Gearing is gearing, a different axle won't change the ratios at all because the ratios are solely a function of the pinion and ring.
cant put 5.38 in toyota axle, cant put 5,29 in dana or i would have


I've heard you can be within like .01 gearing change (4.10 vs 4.11) but have nothing to base that off of. 1 inch of 110 doesn't seem like much, but that's still 1" that has to slip, which when you factor in a high friction/traction surface that's a lot of force and binding going on.

apparently this is correct live and learn i guess :brick:

 

[snow junky]

Is this recent, or better question, has it ever been drivable with this combination?

I'd tend to lean towards driveshaft angles if it hasn't ever been drivable. You're within 2% (not within 1%) on gear ratio differences, which is borderline.

This is the difference as a percentage of the smallest number of the two ratios. It isn't 4.11 minus 4.10 for example.

5.38-5.29= 0.09

0.09/5.29=0.017 or 1.7%.

havnt done much driving around in 4wd on the street but i think i remember it working ok on the street.... i chanced the dana style yoke to toyota with the new spline and a wheeling trip and thats all that changed

if it works on on the dirt then i think the angles ok.

 

[mxer]

Notice how I said the vibrations are in a strait line......

Are your tires the exact diameter? If one is more bald than the other or even different air pressure I would suspect it would reek havoc with a welded differential.

 

[IBallEngineer]

I am missing something here, why are you attempting to use 4wd on dry pavement?

I have never known of anyone doing this without some binding/noise/vibration.

I know you said it's there in a straight line, but as many have pointed out, you have the tires rolling radius, and the slight gear ratio variance working against you. If it works in 2wd, and works in 4wd where it SHOULD be used, I don't see a problem.

Or am I missing something?

opcorn: