Driveline Setup - Vibration And Power Loss Through Excessive Driveshaft And U-Joint Angles 

I was taught that if a u-joint doesn’t have at least a little off-axis motion on a regular basis, it will cause Brinelling and premature failure.

Great video- excellent explanation especially because FEW BUILDERS take this important aspect seriously enough to have this conversation. I can only imagine the errors for anyone NOT considering it. Thanks

The rear pinion angle of -3° to -5° depends greatly on what crankshaft/tail shaft angle you have up front. Each vehicle has a slightly different crankshaft angle.

The engine is placed at the industry standard of 3 degrees down and the axle pinion placed at 3 degrees up. This takes care of the joint lube issues. Since the universal joints are not made to work completely straight. The needle bearings need enough angle to make them roll in the lube. That's how they are assembled. And the u joint manufacturer also explains that.

Good stuff to know! I can see a lot of different vehicles with problems, especially trucks with lift kits. Maybe they have CV joints, but maybe not. This is something else that is overlooked way too often.

You’ve got so much knowledge up there man, glad you are able to share it with us!!

After picking up my 1st Mopar Build, I can clearly see why Mopar guys talk about U-Joints & Transmissions. Mopar really stretched the limits on their angles (esp in early A-Bodies) where as GM & FoMoCo kept them a lot straighter. Definitely a challenge to change up an early A-Body, but one I fully embrace. Great video as always UTG! Keep them coming.

This is a great video. Thanks!

Had many K5s my new 90 rr u joint would have to be replaced every year . Finally had new drives haft made heavy duty. They told me that alot of trucks bang drives haft being unloaded off car carriers from factory .Who would guess that .This rear end angle under load is right there and I never caught that! Darnitt!! Luv you guys!!

From my experiences and as noted by specific scientific literature on using hookes joint universals, the aim is to cancel out variations in the rotation speeds (changes in velocity) of these joints when they work in pairs at an angle. The usual method is to ensure that both the crankshaft & transmission line and the pinion angle line of the rear gear set (in a traditional front engine rear wheel drive car) are both parallel to one another when viewed from the side. It doesn't matter if the differential or engine/trans combo is higher or lower than each other, as long as they are parallel. Setting up the driveshaft in this manner effectively cancels out the differences in velocity changes in the rotational speed of hookes type universals due to the opposing universal joint compensating for the other. A perfectly level driveshaft using hookes joints is a no no, as there has to be a slight difference in angle otherwise the needle rollers within the joint won't rotate (as they are a bearing) and the universal joint will have a very short life. The rollers will effectiively dig into the journal surface creating gouges. Not mentioned also, is that they should also be phased correctly to one another if using a slip yoke type tailshaft. A novice enthusiast may not be aware of this and fit a hookes type universal totally out of phase with its partner at the other end. This is more common on cars that run a flange on the rear of the transmission and not a sliding joint. Centre bearing driveshafts need to be setup carfullly and thoughtfully if driveshaft vibration is to be avoided. Just my 2 cents Tony. I enjoy your presentations.

Great information as always

Tony is correct. Everyone needs to watch the video at Garage Fab about pinion angles and driveshaft vibration.

I had vibration in my old van that shook the floor and found missing rubber from motor mounts, bad transmission mount, worn transmission tail shaft bushing, (even replaced the yoke) and bad U-joints. It took all of that to get smooth again.

Those Nolathaine bushes you are replacing the rubber with work quite well I have had them in my 69 Valiant for the last 20 years and they have held out quite well. Down under in Australia the factory manual specifies to use a tap to remove the cup if it is worn out. Recommended tap is ( Inch and 3/8 12 threads per inch. They come out very easy using this way on a press if someone is choosing to replace bushes with rubber PS I like your technique as not everyone can get their hands on a tap. We also had upgraded lower control arms in the later model valiants which were plated on the ends of both arms to prevent the lower arms from distorting and result in the bushes prematurely wearing out. These arms also were an option on police vehicles. Keep up the good work Tony

Thanks , great video.

Right after I read about Mopars' penchant to drop the front of the shaft and attempt a pole-vault, my 72 Challenger tried it. Luckily I only had to ride the bus with the whole shaft to get it fixed.

If you cut the tail shaft & re weld make sure the uni joints are put back in line the same .The angle should be the same front & rear also.I had to line up a GE Jet Turbine once to a gear box with a short about 1M long tail shaft .It had to have a bit of offset both ends to work the roller bearings like other people have said.If you have angle only on one end you get all the vibration to the wheel.If both ends are the same but to excessive a angle its mostly the tail shaft that vibrates depending how heavy it is.Someone in Australia invented a double Yoke set up to handle much bigger angles.

Check out Dick Landey's books on kinda primitave mopar suspensions for drag racing. We aplied it to a ford and it worked! Nobtraction bars or extended shackles. We moved the leaf springs rear but put the rear end 1/2" foreward. The car lifted the rear and went. Bent the frame and the doors wouldn't open!

I did lots of stuff in this area and one of the issues is if you can't make a straight driveline (most of us) keep the angles equal between the from and rear universals to reduce vibration. I have seen many jacked up cars that forget that issue and are terrible to drive on the street do to the vibration caused by that setup is undrivable in a cruise car.

As a derby driver that years ago used to run only stock parts meaning non purpose built derby parts. I can say stock parts can take alot more than people think even at crazy angles

Driveshaft CV joints are also called Double cardian joints .Also don't forget about drive shaft phase . Great video.

Another good one, Uncle Tony. Thanks!

Getting the drive angle right for the application is critical. Driver fatigue when a driveshaft vibrates it terrible. Not to mention wear on other parts. Like having a bad tooth. It will drive you nuts but its super gratifying when setup correctly.

Finally someone explained the drive train offset! Been trying to find the reason for years. Now I can sleep a night.

That67 coka a cola body style is my favorite.

Another good show Uncle, do a follow up on how to make the angle adjustments with plates between the springs and spring purchases and uses of a pinion snubber. Keep up the good work. the youngsters need someone to show them what we went through without the Uncle Tony's. I'm 68 and restoring a 1972 Duster, 440/ 727/ 8 3/4/ 3.55 posi/ Power steering/ power 4-wheel disc./air conditioning/ Bluetooth radio system. It should be ready to fire very soon and then to the paint shop. Harry

I've been taught that the u-joint angles need to be at equal but opposite angles... and not have one at more of an angle than the other.

My Duster had a driveline vibration for years I finally figured out(by accident) that the center hole in one main leaf was 1/2" further back than the other one.

I just replaced u joints on my street rod. The rear did in fact shave brinelling

If you’re talking about diffs, and driveline angle, you have to discuss Wheel Hop- what Ford did, gm, Chrysler, leaf, coil, and shocks. Manual trans cars, big and small.

Gotta' mention 4x4s! Pinion angle gets more interesting when balancing vibes and handling (caster on a solid front axle).

I’m going to swap a 440 and 727 trans into my 67 barracuda some day. I bought a trans, and engine is underway. I assume I’ll need a larger diameter driveshaft, or custom driveshaft-and just toss (like Uncle Tony likes to do) the slant 6’s driveshaft out to the yard. QUESTION: what clearance do you need at static state, driveshaft yoke to trans…to avoid binding during drag strip launch? I’m guessing this dimension is key to having correct length driveshaft. So much to learn. Thanks!

I had an old jeep that I put about a 5” lift on with big silly tires, and that change in the driveshaft angle turned it into an absolute u-joint eater. About every 15,000 miles I had to pull the shaft and throw new joints in or it wasn’t gonna be pretty.

The remedy for vibration with 5 degrees of pinion angle. Stronger front segment on leaf springs. Then you can run less angle.

I think what you are referring to as a CV joint is a double Cardan, basically 2 U joints back to back. A CV joint is a ball and cup like on FWD cars.

My 68 Firebird has a very slight vibration on the turnpike but when I let the throttle up very slightly, not decelerating or accelerating it goes away. Yes my drive line angle probably changes slightly,, I have constant velocity u-joints on the output trans yoke could I put another one on the rear end yoke??

So on a vehicle with a driveline angle is it a good idea to use a CV style joint? Is there a strength issue? Would you only need that joint at one side of the drives haft? My 93 dodge Cummins uses a CV at the front drive shaft but not at the rear and there is an angle. At around 50 mph you can feel a bit of vibration but above or below that it's fine.

AWESOME vid UT. So true on the MOPAR drive train...fyi i HATE you that you can be on your knees this long through out the video...lol MOPAR 4 EVER.

What is that heavy disc on the front of the drive shaft? Since one can't apply a driveshaft brake to a swinging part like that, is that there for balancing?

Speaking of driveshafts, what determines diameter? Is bigger stronger? My C3 corvette drag car has a small dia. shaft. About 2-1/2". The GMC pickup I tow it with has a shaft twice that size. Is it a matter of available space? Does length matter? The tiny shaft in the Vette ( which is very short) handles 750 HP and never had a problem.

I always thought that there was supposed to be a few degrees of angle at both ends of the driveshaft. I thought it was supposed to be equal angles at both ends. Just a few degrees. I can't remember where I heard that. But I'm more confused than ever now.

so..raiseing or lowering the ride hight of the car (espesicaly) in the rear will affect your driveshaft angle...correct?...and put more of a load on your u-joints,tail shaft busshing,ect...correct...?..great video U.T.....thank u..!

On my 4link I have the pinion angle @ -4 degrees. So that it squats when it leaves the line.

I got something out of that. Kiwi touched on this a few weeks ago, with that Mustang gearbox conversion.

Great stuff!

I don't know about this one.

I'm having some kind of vibration and squeak in my drive shaft, and will have to take it off and examine it.

The steering box is usually on the left, therefore the engine would be offset to the right. So you would want the pinion to be offset to the right as well.

PRICELESS.Thanks 🙏

Tony, I think my truck may have this problem. I hear a pulsating noise in the cab. I put clamps on the leaf springs in front and behind the perches to stiffen them up and that helped reduce the problem. Anyway, I was curious what it actually sounds like and if it is a pulsating / droning noise? My vehicle is a 1976 K20 chevy truck with a SBC 350. I have a 2" lift over stock. I have measured angles and my pinion is set 2 degrees nose down with shims to account for torque during acceleration. One thing I did not consider is the angle from side to side. I will have to check that out.

you blow me away Mr. Tony. The ford 9" takes the slack, so to speak.?

I still haven't figured out how u-joints work, though: when they're vertical (like an upright cross) the up and down movement they allow is obvious. But turn them 45 degrees so they form an X and they're rigid--they don't appear to allow vertical movement at all.

Seeing u working on ur charger makes me wanna work on mine more and more

Great video ! Cardan joint. I’ve 3 1 tons. Variation of a CV joint of sorts. And they too can be rebuilt but they suck and it helps to have an extra set of hands ! Ball bearing in between two u joints and that wears too …..

The engine/trans offset to the passenger side is a Mopar thing. Almost no other company did that. As long as the shaft centerlines are parallel, except for spring wrap, everything equals out. Almost imperceptible power loss. JMO

Didn't check all the way down; did anyone ask about center-bearing drivelines? My old Nissan Frontier and my '87 Ford Ranger 2.9L use rubber-mounted center-bearings connecting two short driveshafts. How do they fit in?

What’s the recommended crankshaft/trans angle? 0°, -1°, -2°, -3° etc?

i got my 66 gto then i got a 75 Bonneville found that a lot parts bolt right on the 400 turbo and drive line went right in the power trunk bolted right in the electrics on seats bolted right to the buckets under the hood light the tilt wheel plus it had a 455 that i put in funny part is i got the 66 gto for 500 then picked up the Bonneville for 100 buck running and driving just had a smashed 1/4 panel the tri power i got cost 800 which was more then i had in the car but worth it i built that when i was 15

Except Chrysler always has u-joints offset looking down or up vertically from the ground. Specifically so that as the axle raises or lowers in relation to transmission it will never line up and cause a vibration. You do not want much offset, but you must have some or a vibration will result. This is illustrated in the Mopar/direct connection books

This means I need to check and see if the carrier bearing is going bad in my truck and causing the angles to be off. I hope that is all the problem is, because that will be the cheapest fix.

Always wondered if offset position of the engine in the engine bay was because of the driveshaft.

All my C-bodies had CV joints.

When I set up my ford 8.8 rear end, and a 46rh I set my pinion angle at 3.5 degrees down pinion, and my tailshaft at 3.5 degrees down. Did I do that correctly?

Youll see it on monster trucks, the transmission’s tail is angled down

I still remember seeing a garbage truck driveshaft lying in the street in front of high school. It was twisted like a stick of licorice. I always wondered how that happened?

Why does the auto trans tail shaft is so long? Like what does it even house in it that its as long as the actual transmission part itself?

Enter my 75 blazer i had with 8 inches of lift and 38 inch super swampers my drive shafts looked like chop sticks

What about Double Cardan Joints

I'd love someone to point me in the right direction with a problem I've been having. I have a 74 charger with a 91 dakota power train, was told the driveshaft was from a 68 dodge pickup and the rear end is the factory 8 1/4 with 2:76 gears. My problem is this, up till 85 nothing is wrong but beyond 85 I start having a pretty noticeable rumble, it's not constant, kinda like a horse gallop, lugaluga....lugauga.....lugaluga. and as you go faster it'll calm down a little but it's still there, if you let off the throttle it'll be a little more violent, at 130 it's more or less gone, it's there but you barely notice it either because it's rotating so fast or evening out. I want to say it's the driveshaft not being balanced but in my 69 the 904 shaft was shortened for a 727 and it would make it to around 65 and be so bad you couldn't possibly take it faster and expect that car not to fall apart it was a constant very violent rumble that would get rougher and rougher. The 74 has been like this since I bought it a year ago and I put in new ujoints a year ago along with a rear seal and I take it this fast almost every day and the seal is still good along with the joints. Am I correct in thinking that whoever shortened the 68 pickup shaft didn't balance it correctly or is it something else?

GTR R35 driveline is arranged in a way where the angle becomes straighter under load.

Anyone found that having around a 3 degree angle down on the pinion provides better rear end squat on launch? Conversly having the pinion pointing up 3 degree's will cause unloading of the tyres and wheelspin on launch.

A straight u-joint needs some angle or it won't lubricant too much will bind. 1/2-3° is about ideal

hi it's your special friend lol

You talked about parasitic drive loss but not the driveshaft speeding up and down when the u joint runs on an angle hence the other end needs to do the opposite..trans and diff angle needs to be in the same plane a grocer getter

Anybody know where those 3 young guys Austin with the car UT give them what happened

THIS problem is why LINCOLN engineers, designing the '61 - '69 uni-body Lincolns, prescribed "double-cardan" constant-velocity joints at both ends of their driveshaft.

Great timing for me!

I got something outta that

Tony has always been my hero !!!

Al Go Rhythm

How does this apply to ball and trunnion joints?

Couldnt a CV arrangement be incorporated in the drive shaft? That seems to be the solution, although probably costly.

Tony you forgot to paint that transmission 😅

This is great info. I was taught that the rear diff needed to be parallel with the tail shaft to where the offset angles matched. Is it better to angle the rear to point to the tail shaft if angling the transmission isn't ideal? To where only 1 u-joint has a slight angle vs 2? Hope this question makes sense. Thank you!

Hi Tony what do you think of holley 2BBL for example the 2245 ?

Another great one Tony but you sure stirred up some folks

?? 😶 So what's happening with project impossible 318? Or whatever it's supposed to be called. And Bottle rocket. So, we're doing nothing to it, meanwhile Casper is building the fastest damn truck in Tennessee. 😳 Tony's talking about driveshafts. It's probably the squirrels damn fault 🐿️

Seriously, did Kiwi find a 265 to bring back to the US???

Better tell the engineers who designed straight front axles that there mis useing the outer u joint in that application!

Ujoints that don’t have angle will not center the drive shaft while spinning causing premature failure.

Might as well do a video about front end alignment as well then, ride height vs under load scrub toe. Max suspension stroke to ride height differences. I love how you teaching the kids the tricks to getting stuff right.

The 5° downward angle of the yolk at rest should only be applied to vehicles with leafspring rear suspension. If the vehicle is converted to coil overs and/or has any type of four or five Link suspension then this is unnecessary and will cause premature failure of the differential.

Hey, Uncle Tony, I have a myth for you to bust or prove to be true. It may be good content for a short video. When I was a kid in the 70's I used to hear about people putting 'Moth Balls' in their gas tanks to increase the Octane of pump gas. If you don't want to make a whole video, could you maybe leave a short reply on your thoughts? Just about everything I know about cars and hot-rodding I learned from people like you. Thanks for keeping old school car knowledge alive. Thanks.

I think you're off on this one UT. Out of the thousands of different models of vehicles produced they were never set up with zero angles on the drive shaft. Ideally you want the transmission (down) and the pinion angle (up) to match. I think you were also trying to imply running the u joints at an angle causes speed variations? I've heard that somewhere else but that's false. The angle causes the caps to run in 2 different planes but at the same constant speed. If you think one set of caps as speeding up and slowing down the other set would be doing just the opposite at the same time. Kind of an impossible situation.

I have a build where there is no suspension on the vehicle and planned to hook the tranny directly to the rear with a splined dragster coupling. Will it hold up on the street. It's a Mark Williams dragster coupler.

There a lot of lifted trucks around here, (the owners are sweating bullets), If they had watched this video

FIRST.....ROAD TOADS

I thought the double u joint was a cardon joint

I’m hating life right now. Thx uncle tony Not that u made it worse. U ground me

Uncle Tony you are so wrong on this, the engine/transmission crankshaft/transmission output shaft has to be parallel to the rear end pinion shaft centerline but at an angle. the engine/trans centerline can be higher or to the side of the rear end centeeline. There is a degree angle, I want to say 30 degrees that is the most you want to go. I have made front driveshafts for high lifted Toyotas that universal joints had plate that bolted to plate on the trans shaft and one on the pinion and the drive shaft had a slip shaft like a power take off shaft on a bush hog mower, these trucks had 12 inches of lift or more to clear oversize tires. where the universal angle will be too sharp, folks use a CV joint Bumps and hog head twist on acceleration are acceptable variations to a point. Pointing the hogs head upward or having you motor/trans at a downward angle so the pinion/driveshafts/trans shaft/crankshaft is on a straight line is WRONG!! You want the centerlines parallel with driveshaft at an acceptable angle the same on both ends at rest...the universal joint is designed to run on a slight angle no matter if the driveshaft is 3 inches or 30 feet.