Yukon 5.29s installed! Question...

[4WD Toyota Owner Magazine]

Got the Yukon 5.29s in front and rear today...no real problems...got the axles in and out after locking the diffs etc...cool.

Question: there is basically no new noise or NVH up to about 50mph. Then it gets "grinding" in sound. Not horrible, like it's flying apart or grenading, however, but definitely a grind-style noise. Sometimes it happens when I let off the throttle from 70 and let it coast, and it'll happen when I'm accelerating back up again. There's also just a touch (not a lot) of vibration I can feel at my feet.

Any ideas? Thank you!

 

[ginericLC]

Sounds like the pinion is not adjusted correctly. Could be driveline vibrations too. But since you just swapped gears I'd go for the pinion first. Also, any chance the driveshaft got out of phase while the work was being done?

 

[Hondo]

did you follow normal break in procedures? seems to me like most recommend low speeds for first couple hundred miles...

ie. http://www.performanceunlimited.com/documents/gearbreakin.html

http://www.ring-pinion.com/content/technicalhelp/default.asp?pid=122

 

[helocat]

Dave,

It may also be vibration coming from your drive shaft. Now that you have the lower gears your drive shaft now turns considerably faster to maintain the same speed.

OD aka 4th, with your A442F automatic transmission is 0.765:1

With 5.29 gears your drive shaft now has to spin 1.19 times more just to = one revaluation your 4.10 gears did for the same speed.

So say with 35” tires your drive shaft spins at 2362 RPM when you are going 60 MPH with the 4.10’s.

Now to do the same speed with the 5.29’s you drive shaft now has to spin at 3047 RPM just to maintain the same 60 mph road speed.

So your drive shaft now thinks your doing 77 MPH when you are really doing 60 MPH. This extra speed it has to spin to accomplish the same speed will start to magnify since these are sustained speeds at a lower road noise. (Road noise at almost 80 is much different than at 60!) So we hear stuff that we may not have before.

Ok all that said, almost all aftermarket gears make some noise.

Mark

 

[cc93cruiser]

Dave,

It may also be vibration coming from your drive shaft. Now that you have the lower gears your drive shaft now turns considerably faster to maintain the same speed.

OD aka 4th, with your A442F automatic transmission is 0.765:1

With 5.29 gears your drive shaft now has to spin 1.19 times more just to = one revaluation your 4.10 gears did for the same speed.

So say with 35” tires your drive shaft spins at 2362 RPM when you are going 60 MPH with the 4.10’s.

Now to do the same speed with the 5.29’s you drive shaft now has to spin at 3047 RPM just to maintain the same 60 mph road speed.

So your drive shaft now thinks your doing 77 MPH when you are really doing 60 MPH. This extra speed it has to spin to accomplish the same speed will start to magnify since these are sustained speeds at a lower road noise. (Road noise at almost 80 is much different than at 60!) So we hear stuff that we may not have before.

Ok all that said, almost all aftermarket gears make some noise.

Mark

+++++thread hi-jack+++++

Do you think this would explain why I have gone through 2 rear pinion seals with my newly installed 4.88's? I can't explain why? There are no vibes, grinding noises or whinning sounds, nothin.. The differential shop told me that the driveshaft might not be balanced correctly, but I have no vibes at all( wouldn't it be causing bad vibes if my driveshaft was not balanced correctly?) Sorry for the hijack, but I was wondering if there are any of the same problems out there that I am having with my gears....

 

[cc93cruiser]

The shop told told me that I have to replace the rear pinion yoke... That there is a slight groove that is causing all the leaking from the pinion oil seal....

 

[landtank]

my Yukon 4.88s were a little noisey as well but now that they are broke in with 100k on them they are fine.

 

[OGBeno]

Dave,

It may also be vibration coming from your drive shaft. Now that you have the lower gears your drive shaft now turns considerably faster to maintain the same speed.

OD aka 4th, with your A442F automatic transmission is 0.765:1

With 5.29 gears your drive shaft now has to spin 1.19 times more just to = one revaluation your 4.10 gears did for the same speed.

So say with 35” tires your drive shaft spins at 2362 RPM when you are going 60 MPH with the 4.10’s.

Now to do the same speed with the 5.29’s you drive shaft now has to spin at 3047 RPM just to maintain the same 60 mph road speed.

So your drive shaft now thinks your doing 77 MPH when you are really doing 60 MPH. This extra speed it has to spin to accomplish the same speed will start to magnify since these are sustained speeds at a lower road noise. (Road noise at almost 80 is much different than at 60!) So we hear stuff that we may not have before.

Ok all that said, almost all aftermarket gears make some noise.

Mark

Great explanation Mark. Thanks.

 

[LandCruiserPhil]

The shop told told me that I have to replace the rear pinion yoke... That there is a slight groove that is causing all the leaking from the pinion oil seal....

More hi-jack

Bad balance will eat pinion seals. A slight groove normally takes a little time to leak. You can shim the pinion seal out to avoid the groove if thats the problem. My guess is new drive line speed combined with out of balance.

hi-jack over

 

[4WD Toyota Owner Magazine]

great info mark--thanks!

getting it checked tomorrow will report back then!

 

[4WD Toyota Owner Magazine]

Got it--the faster spinning shafts caused already tired u-joints to have their death rattle. Got new u-joints from local Toyota dealer front and rear, will install tomorrow.

 

[montocr]

will need a double cardan shaft

You will need a double cardan shaft at least for the front going over 3". The rear may need one at 5" +.

 

[FJBen]

You will need a double cardan shaft at least for the front going over 3". The rear may need one at 5" +.

Not true...this is a vehicle by vehicle debate...I'm running a 4" lift with the stock driveshaft, no or extremely minimal vibes that i can tell.

 

[Tapage]

Not true...this is a vehicle by vehicle debate...I'm running a 4" lift with the stock driveshaft, no or extremely minimal vibes that i can tell.

I thought it depends how much weight you have in your cruiser .. so the real lift was afected.

 

[landtank]

it all depends on how much you rotate the axle to correct for the lift. The amount of lift also factors into it but not that much. FJBEN has actually rotated past the need for a DC Shaft with Slee's arms. If he had more accurately targetted his caster to 3* he probably would have needed one.

 

[nakman]

Amount of weight directly correlates to amount of lift though, so they can't be labeled independent of each other when determinining castor correction. Presuming FJben has a front bumper & you don't, YMMV. From my investigative reporting a couple weeks ago I learned Alvaro runs the same setup as Ben (Slee 4", Slee arms, stock DS) and also has no vibration. so 2 data points

 

[montocr]

double cardan

I have had a coupl of these rigs w/ just about any spring/weight combo. The front over 3" count on doing a double cardan. For the rear on my 96 I couldn't go over 4-5" even w/ adjustable rear arms. If you get a noise (like a chatter or growl) on light accell/decell/float thats the noise. I run 4.88 in all my trucks and experienced the rear problems over 60 mph +. Had it been stock gears it may not have been noticeable untill a much higher speed.