This kind of has me wondering...i just put my high pinion dana 60 in my 70 f-250, this helped my u-joint angles significantly. With the low pinion i didnt notice much vibration and never broke a shaft. With the new angles will i have to worry more about breaking shafts/more vibrations?

 

Only if your pinion is on the exact same plane as your T-case. Meaning your pinion would be completely level, rear pinion pointing straight at your front axle, not up at all. Most are slightly turned up and the pinion angle can change depending on shims, shackle flip, spring placement, etc when lifting the truck. Does this make sense?

 

i think so, i was finding my angle the wrong way, i was just measuring the angle of the driveshaft. but i googled the pinion angle and found i need to subtract the angle of the driveshaft from the angle of the pinion flange to get the pinion angle. is that right? so i got a pinion angle of 2 degrees on my stock truck...does that sound right?

then, if i calculated it right, with 4" of lift, it should put the pinion angle at about -1.8 degrees?

-jason

 

i have run them like you said with 0 degrees at the piinion before too

the reason they are supposed to be at the same angle is to cancel out the vibrations from each joint's eliptical motion. its not noticable at small angles, but when you get up to steeper angles at the x-case, and you have the pinion pointed at 0 degrees, it vibes pretty bad

plus one thing i like to do, even on a cv shaft, i always like the pinon to be popinting down 2-3 degrees at rest, so when your cruising the pinion is at or near 0 degrees. the compensates for some axle wrap

ill stop rambling

 

2* is an almost non-existant angle, I don't think that's right. The easiest way to find your angle, though not exact, is to take a 50 cent protractor and line it up with the yoke on your t-case. Hold it so the straight edge of the protractor is up and the round side down. If you imagine the output shaft continuing straight past the yoke you'll want the flat side even with this. If the protractor is centered on the yoke note where on the round side the driveshaft falls. This will show you your angle. You can also do this with an angle finder, I just have noticed that people often don't take into account that the ground they're on isn't perfectly level and sometimes the T-case doesn't sit level in the frame either.

 

i used a protractor with a weight suspended by a string on the protractor...lined up the flat side on the driveshaft and found that angle was 7 degrees, then the angle at the pinion flange was 9 degrees. 9-7=2 degrees.

http://www.steeda.com/-techtips/pinionangle.htm

don't know if i did that right though

-jason

 

I believe it is recommended that you not exceed 5* max angle per ford manuals unless your using a double cardan joint.

 

All u-joints are cardan joints. You mean a double-cardan or CV?

 

a double cardan joint setup is the real name for what we refer to as a cv joint. A cv joint, has a true constant velocity in its range of motion like the cv axles used in front axles, where as a double cardan joint just almost have a constant velocity

 

I just wanted to pop in on the pinion angle topic as I raised my truck 6" front and 3" rear. I have a F350 Crew Cab long bed 2WD. I was looking at pinion angle and the carrier bearing. The two driveshafts are at different angles to each other, but I can't tell angle of tranny vs. pinion without some gauge.

Jason pointed out earlier that it seems tranny angle to pinion angle wouldn't change just lifting the rear end. I tend to agree (I'm aware pinion to driveshaft angle would change). Going on with this, my lift kit came with tapered blocks with instructions to put the smaller part of the block facing the front of the truck thereby raising the pinion angle.

Does it make a difference that I have two driveshafts?

 

thats only if you buy a lift system with rear springs do they come with tapered blocks. but you're right, with a system it usually doesn't change b/c the manufacturer has built the system per certain specs. and you would want the small side pointing towards the rear to lift the front up... if you were wanting the pinion to point up a lil more.

no it doesn't makea difference 1 2 or 30 driveshafts, you will still have some sort of angle any way you look at it. its just you dont look at your pinion at the tranny/t-case, you look at the angle where the shaft drops down to the rear axle.... ie the rear shaft and not the shaft hooked directly to your tranny!

i went to home depot and bought an $8 angle finder! its awesome and theres no guessing. its what i used to help me setup my shackle angles and get them perfect! i highly recommend everyone getting one b/c there is always a use!

-cutts-

 

Home Depot would be my favorite place if not for the checkout lines. I'll look for the angle finder. I just spoke to an "installer" today who said I probably just need to lower the carrier bearing and I'd be fine having not changed springs. His rule of thumb on lowering the carrier was 1/4 for every 1" at the axle. I'm one of those worriers.

 

When I did my 4" lift it included the tapered block that Drew Worm mentioned. My truck also has the two piece driveshaft and at 60 to 65 mph the truck had an evil vibration in the driveline. To correct this I experimented with dropping the center carrier bearing. I made a bracket that would allow me to use heavy steel washers to space it down in increments. I would have to go out and measure the exact thickness, but it is in the ballpark of an inch lower and this depth has eliminated all but the faintest vibration. So, as the installer said, 1/4 inch per inch of lift height isn't all the far from reality. What I really need to do is get an angle finder like FISH said so that I can really hammer down the exact angles.

All that being said, it has been mentioned more than once that the rule of thumb for setting drivline angles is to keep them the same on both ends. On a vehicle that has a 2 part driveshaft with a center carrier does this still apply? Regardless of the method of lifting be it blocks, springs, shackle reversal/flip the rear axle is still being lowered a given distance from its original height. So, on these multi part driveshafts, which are the critical joints to match the angles on? Looking at the way my truck was set up, initially it appeared(I didn't actually measure) that the t-case joint was relatively close to zero degrees in relation to the carrier. What appeared to be the evil nasty angle was the joint on the rear of the carrier. By dropping the carrier, it decreased that angle, but increased the angle on the t-case.

So, to simplify my question, is there some rule of thumb that applies to multi part driveshafts, or is it just experimenting to find a happy medium between the three joints? The way I did mine was pretty much just an educated guess, but I will hopefully be eliminating the blocks before long so I will have to re-adjust things all over again. To have a hard and fast rule to follow would be awesome.

 

I think the point you are missing is that a regular spring or block lift does not change the pinion angle because the lift is fairly equally divided between the front and rear mounting points of the spring; on the other hand, a shackle lift (or shackle flip) only changes the spring's position relative to the frame at one end. Hence it changes the angle of the axle pinion by rotating the axle assembly. Is this any clearer?

 

SORRY GUYS. Wrong thread.