Tilting the front Diff. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tai6mai9shu · 03-21-2006, 03:34 AM

I have a question about tilting the front diff because my u joint knuckles hit together when in 4wheel drive and i was told if i tilt the diff it will give it a better angle and i wont have the problem, the truck is lifted and its a 84 gmc k1500, i was just wondering if anyone has any idea's, Thanks

Mudder · 03-21-2006, 06:18 AM

The only way it can be done is by moving the pumpkin on the axle tubes without turning anything else. It will totally mess your steering and handling up if you don't.

drink2mny · 03-21-2006, 06:40 PM

How much lift you have???
You can get away with 2-4 degree shim most times.

tai6mai9shu · 03-22-2006, 03:00 AM

What would i be shimming if thats the case? the front of the trans.???
Now i;ve came to the problem that i cant find a u-joint for the front shaft. all the parts stores say someone must have placed a different front yoke on the shaft cause the u-joints are not matching up, wondering if the stock yoke spines will match up so maybe i can put the stock front yoke back on it and then place the right u joint in there. any way i can find out how many splines the front yoke for the front drive shaft has?
Thanks

tai6mai9shu · 03-23-2006, 02:58 AM

I found a u-joint and have it installed and it seems to be ok, havent' put it into 4wheel drive yet had to get to work shortly after installation. any ideas on how to move that front diff, if i still get my knocking sound? and i have to get two new drive shafts anyways because someone added some to it and welded them im and they are no longer ballanced, i want to get some square tube ones but i have no idea where to find them. any help would be greatly appreciated.
Thanks

qksilver · 03-23-2006, 11:29 PM

square tube drive shafts? they won't work........since the drive shaft rotates they need to be round so that the torque of twisting/ torsion is spread over a large area. Square tubing would localize the torque and bend them

drink2mny · 03-24-2006, 09:41 AM

Actually alot of off roaders use square tube driveshaftsbecause you can get alot of slipout of them. They just weld on the yoke ends and just put a smaller tube in a bigger one and call it good..

You never did say if you had a lift on your truck and or what year it was..
as for a quick shimming answer, you would order or go to an offrad store and get them. They would be put between your front springs and the spring pads on your axle..

You mentioned you had to get a different u joint to hook up the front. Those are called conversion joints. Usually needed when some one either has changed the output yoke on the diff or has a different year driveshaft.

LONGHAIR · 03-24-2006, 10:08 AM

As drink2many said, the square tube definately does work, but I don't know that I would run one on the street. It's more of a rock-crawler off roader type thing. Speed and balance and over-all mass being the issues.

Also as drink2many asked, you never did say how much lift..........This is an important factor.

I am not a big fan of the shimming on the front axle though. It doesn't really gain you very much clearance in the yoke an it will cause steering issues. You are doing more against the steering (castor) than you are for the driveshaft angle.
If you have enough lift to have a driveshaft angle problem it is likely that you have much bigger tires too. Larger tires will exaggerate the castor problem. The proper castor angle helps the truck keep tracking straight and reduces the tendancy to wander.

As Mudder67 said, there is a way to do this right but it is going to take some work. Don't let anyone talk you into rotating it too much though. This causes problems too. You don't want your u-joint angle to be too straight. This can make too much difference between the upper and lower joint angles. Tilting too far can starve the outer pinion bearing of oil too.

tai6mai9shu · 03-30-2006, 03:48 AM

it has a 9 inch lift on 36's there are no springs or blocks its all leaf's that are lifting it. no extentions on the leaves to lift it up no blocks at all.. strickly leafs. its a 84 gmc k1500,

03-21-2006, 03:34 AM	#1
tai6mai9shu Registered User Join Date: Mar 2006 Location: Williamsport PA Posts: 13	Tilting the front Diff. I have a question about tilting the front diff because my u joint knuckles hit together when in 4wheel drive and i was told if i tilt the diff it will give it a better angle and i wont have the problem, the truck is lifted and its a 84 gmc k1500, i was just wondering if anyone has any idea's, Thanks

03-21-2006, 06:18 AM	#2
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Re: Tilting the front Diff. The only way it can be done is by moving the pumpkin on the axle tubes without turning anything else. It will totally mess your steering and handling up if you don't.

03-21-2006, 06:40 PM	#3
drink2mny Registered User Join Date: Jun 2003 Location: spokane wa Posts: 2,189	Re: Tilting the front Diff. How much lift you have??? You can get away with 2-4 degree shim most times. __________________ Support The Board

03-22-2006, 03:00 AM	#4
tai6mai9shu Registered User Join Date: Mar 2006 Location: Williamsport PA Posts: 13	Re: Tilting the front Diff. What would i be shimming if thats the case? the front of the trans.??? Now i;ve came to the problem that i cant find a u-joint for the front shaft. all the parts stores say someone must have placed a different front yoke on the shaft cause the u-joints are not matching up, wondering if the stock yoke spines will match up so maybe i can put the stock front yoke back on it and then place the right u joint in there. any way i can find out how many splines the front yoke for the front drive shaft has? Thanks

03-23-2006, 02:58 AM	#5
tai6mai9shu Registered User Join Date: Mar 2006 Location: Williamsport PA Posts: 13	Re: Tilting the front Diff. I found a u-joint and have it installed and it seems to be ok, havent' put it into 4wheel drive yet had to get to work shortly after installation. any ideas on how to move that front diff, if i still get my knocking sound? and i have to get two new drive shafts anyways because someone added some to it and welded them im and they are no longer ballanced, i want to get some square tube ones but i have no idea where to find them. any help would be greatly appreciated. Thanks

03-23-2006, 11:29 PM	#6
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: Tilting the front Diff. square tube drive shafts? they won't work........since the drive shaft rotates they need to be round so that the torque of twisting/ torsion is spread over a large area. Square tubing would localize the torque and bend them

03-24-2006, 09:41 AM	#7
drink2mny Registered User Join Date: Jun 2003 Location: spokane wa Posts: 2,189	Re: Tilting the front Diff. Actually alot of off roaders use square tube driveshaftsbecause you can get alot of slipout of them. They just weld on the yoke ends and just put a smaller tube in a bigger one and call it good.. You never did say if you had a lift on your truck and or what year it was.. as for a quick shimming answer, you would order or go to an offrad store and get them. They would be put between your front springs and the spring pads on your axle.. You mentioned you had to get a different u joint to hook up the front. Those are called conversion joints. Usually needed when some one either has changed the output yoke on the diff or has a different year driveshaft. __________________ Support The Board Last edited by drink2mny; 03-24-2006 at 11:51 AM.

03-24-2006, 10:08 AM	#8
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: Tilting the front Diff. As drink2many said, the square tube definately does work, but I don't know that I would run one on the street. It's more of a rock-crawler off roader type thing. Speed and balance and over-all mass being the issues. Also as drink2many asked, you never did say how much lift..........This is an important factor. I am not a big fan of the shimming on the front axle though. It doesn't really gain you very much clearance in the yoke an it will cause steering issues. You are doing more against the steering (castor) than you are for the driveshaft angle. If you have enough lift to have a driveshaft angle problem it is likely that you have much bigger tires too. Larger tires will exaggerate the castor problem. The proper castor angle helps the truck keep tracking straight and reduces the tendancy to wander. As Mudder67 said, there is a way to do this right but it is going to take some work. Don't let anyone talk you into rotating it too much though. This causes problems too. You don't want your u-joint angle to be too straight. This can make too much difference between the upper and lower joint angles. Tilting too far can starve the outer pinion bearing of oil too.

03-30-2006, 03:48 AM	#9
tai6mai9shu Registered User Join Date: Mar 2006 Location: Williamsport PA Posts: 13	Re: Tilting the front Diff. it has a 9 inch lift on 36's there are no springs or blocks its all leaf's that are lifting it. no extentions on the leaves to lift it up no blocks at all.. strickly leafs. its a 84 gmc k1500, __________________ 84 GMC K1500 Lifted 9 inches on 36's "Lift it, fat chicks can't jump"



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