Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: Vinman on February 12, 2012, 06:48:37 PM
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05 LJ Rubicon.
Stock suspension, no lift yet.
33 Engineering belly-up skid
1" MML
Adjustable rear upper control arms.
I get a nasty vibe starting at 60 MPH and continues as speed increases.
I have played with pinion angle from about 2.5 degrees below driveshaft to 1 degree below DS angle, no change at all.
- New CV shaft just built
- Vibes are much worse with CV shaft then with stock shaft and stock CAs.
- Absolutely ZERO vibes at any speed with rear shaft removed.
Am I missing something here? Any ideas? Maybe a bad driveshaft balance?
Any input is appreciated.
Vince
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How much does the Belly up brings everything up? ... may be you need more then 1"MML.
With a CV you should be ok though...
When I put a tummy tuck on Bonnie's 06 rubi... I raise every thing pretty much the same....1.25 MML+1.5" TT + 1.25" body lift (which des not affect the drive line at all)...
You have a longer wheelbase and a longer driver shaft also. You should be ok.
How's your pinion angle compare to the driver shaft? may be it binds there on the yoke.
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How much does the Belly up brings everything up? ... may be you need more then 1"MML.
With a CV you should be ok though...
When I put a tummy tuck on Bonnie's 06 rubi... I raise every thing pretty much the same....1.25 MML+1.5" TT + 1.25" body lift (which des not affect the drive line at all)...
You have a longer wheelbase and a longer driver shaft also. You should be ok.
How's your pinion angle compare to the driver shaft? may be it binds there on the yoke.
I didn't measure the actual increase in t-case output height between stock and the bellyup but I would guess it's about 2 inches.
The pinion is pointed almost exactly at the t-case so the pinion is about 1 degree below driveshaft angle (to compensate for pinion movement when power is applied)
According to the numbers and angles, I should have no issues with my current setup, well within specs.
Here are a couple of pics.
(http://i40.photobucket.com/albums/e229/vinman02/100_0675.jpg)
(http://i40.photobucket.com/albums/e229/vinman02/100_0673.jpg)
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my best guess is your driveshaft is not balanced properly.
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my best guess is your driveshaft is not balanced properly.
That's what I'm leaning towards as well.
I must be the unluckiest guy in the world when it comes to having driveshafts built or repaired. EVERY time I had one built or repaired the shop got it wrong, this one is no exception. I was very specific when I ordered it that I wanted a greasable center section and NON greasable u-joints. When I went to pick it up, all u-joints were greasable >:( >:( >:( .
I had to make a second trip so they could replace the u-joints. This leads me to the possibility they did not re-assemble it the same way they took it apart resulting in a brand new, unbalanced shaft.
Vince
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my best guess is your driveshaft is not balanced properly.
True...
It might be also the case of empty Labbatt 50 you have in the back of the Jeep ;).
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go have it re balanced and check your pinion bearing if u have any movement in it ..
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True...
It might be also the case of empty Labbatt 50 you have in the back of the Jeep ;).
When I have the top off the Jeep, I hide my wallet under the case of 50, nobody this side of Nova Scotia will even touch the 50
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go have it re balanced and check your pinion bearing if u have any movement in it ..
Zero movement in the pinion bearing, I guess I'll take the driveshaft back for rebalance.
Vince
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looks to me like it is too straight. this will wear out the needle bearings and there will be no .... backforce when the phase of the driveshaft wants to shift. if the shaft can phase in and out at will, it will vibrate. i wouldnt use a cardan for that angle. when my shaft dies i am going without the cardan cause my angles are too strait to have one.
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looks to me like it is too straight. this will wear out the needle bearings and there will be no .... backforce when the phase of the driveshaft wants to shift. if the shaft can phase in and out at will, it will vibrate. i wouldnt use a cardan for that angle. when my shaft dies i am going without the cardan cause my angles are too strait to have one.
I have never heard of a problem like you're describing and lots of vehicles run the double cardons with a relatively straight driveline. The stock front TJ driveshafts don't have much of an angle and don't have any prroblems.
Everywhere I've read suggests the pinion should be pointed directly at the t-case output then dropped about 1 degree to compensate for the diff rotation when under load.
Vince
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All it takes is one of the ujoint cup to installed with piled up needle bearings
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yea, always boggles me. im pretty sure when under load the pinion side of the low pinion will lift upwards. im pretty sure one of the nathans had the same problem with straight or 3 degree +/- angles. i think +/- 5 degrees fixed it. ive seen where they suggest pointing the pinion at the transfer case with a cardan shaft but only recall reading that about TJ's.
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Was the stock flange and dampener removed Vince? If so, it's common with rubi's to have the Lin slide out of the speedo tone ring then fall behind it when you re torque. All which causes a runout issue on the rear output and a subtle vibration.
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Was the stock flange and dampener removed Vince? If so, it's common with rubi's to have the Lin slide out of the speedo tone ring then fall behind it when you re torque. All which causes a runout issue on the rear output and a subtle vibration.
Stock flange and damper was re-used and the damper was never removed from the t-case.
This is hardly a subtle vibe Bill, above 60 mph,this thing shakes like a dog pooping razor blades.
Vince
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where do you guys get the cv double cardans rebuilt?
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Try clocking it 180 to see if it changes at all. If it does, that definately would confirm your balance.
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where do you guys get the cv double cardans rebuilt?
Pat's or DSI
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where do you guys get the cv double cardans rebuilt?
In my garage ;D
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where do you guys get the cv double cardans rebuilt?
Danco. Right by the old DSI over by modern.
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So I took the driveshaft back into Pat's this morning and they initially said my angles were wrong, the angle at the t-case must match the angle at the pinion to cancel each other out.
I disagreed and said anything I have ever seen with a double cardon joint had the pinion pointed straight in line with the shaft less a degree or so.
They agreed to double check the balance and it was off. Apparently the machine had been set up for a DS with a 4" tube and mine was 2-1/2".
I will get the shaft back in tonight but won't be able get it up to speed given the road conditions out here.
I'll report back after a road test.
Vince
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Danco. Right by the old DSI over by modern.
That is where i go, Wherever Cory works is where i follow. Used to be next door at DSI, now at Danco.
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That is where i go, Wherever Cory works is where i follow. Used to be next door at DSI, now at Danco.
Exactly. Cory is without a doubt one of the best driveline guys around, and he treats us better then those big shops.
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Exactly. Cory is without a doubt one of the best driveline guys around, and he treats us better then those big shops.
Well that's good to know, right after I spend $600.00 at Pats :'(
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Exactly. Cory is without a doubt one of the best driveline guys around, and he treats us better then those big shops.
Yiup Cory da dude!!!!!! He da one dat set-up the rear drive shaft for de ol XJ....only had to do it once, good to go!!! ;D
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Re-balanced DS back in and ran it up to about 110kmh, vibes about 95% gone. I should be able to dial it in a bit better with the pinion angle.
Right now the pinion is 1 degree below the DS, should I be going up to a zero angle or down and increase the angle?
Vince
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Down. Increase the angle a bit. U joints need to see some kind of angle for them to work properly
U want those needle bearings moving inside the caps when it rotates if not ull just wear out the u joint by running on the same few needle bearings
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Down. Increase the angle a bit. U joints need to see some kind of angle for them to work properly
U want those middle bearings moving inside the caps when it rotates if not ull just wear out the u joint by running on the same few middle bearings
Thanks Jeff, I'll play around with it tomorrow night.
Vince
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Well that's good to know, right after I spend $600.00 at Pats :'(
diddo, I go to pick up my front ds today at Pats
and yeah 2 degrees below seems to be the standard suggestion