Help setting pinion angle

[N9nefingers]

I need some help from driveline angle wizards...I've been reading and searching but the info I'm finding is either melting my brain or contains links that no longer work. Like this one... http://www2.dana.com/pdf/J3311-1-HVTSS.PDF ...which is a bummer because most threads point to this as the one to follow. I have a '70 C10 with a 350 and T350 with a two piece driveshaft. I have it on bags with Accuair Elevel set at ride height. Currently my driveline points down to the carrier bearing then up at the pinion. I'm thinking this is not correct as that's what I've been reading. But that info is for one piece driveshafts. Anybody got a good link or advice? Any and all help would be awesome.

[HO455]

Here is a good link to the Spicer drive line calculator and a video on how to measure the angles.

https://spicerparts.com/calculators/...gle-calculator

And here is a link to what I did on my Burban scroll to post 348.

https://67-72chevytrucks.com/vboard/...698377&page=14

Once you have recorded the angles on yours then enter them in the calculator. Then you if you need more help you can post them back here.

Just out of curiosity what is you planned ride height?

[N9nefingers]

Thank you for the response...Elevel set my ride height at 29" at the rear fender with 235/75R15 so 29" tires. I have to get my angles as outlined and I'll post those up shortly. I'm pretty sure I did it wrong before.

[N9nefingers]

So here's what I got using two different angle finders...
Trans 6* down
1st driveshaft 7.3* down
2nd driveshaft 1.3* up
Pinion 4.5* down

[Ironangel]

Originally Posted by N9nefingers

So here's what I got using two different angle finders...
Trans 6* down
1st driveshaft 7.3* down
2nd driveshaft 1.3* up
Pinion 4.5* down

Subtract 6* from 7.3* 1.7* Excellent! Subtract 1.3* from 4.5* for 3.1 which is good considering you've lowered the truck. With that understood, the only way to improve that angle is NOT to add a one piece drive line but to cut the factory trailing arm perches off and rotate the pinion up a couple of degrees with new CaptainFab perches...Or, install wedged shims between the trailing arms and the factory perches rotating the pinion up. Thus decreasing the 3.1* its currently in...Jus Sayin

[N9nefingers]

So here's what I got...I went and raised the carrier bearing using the second set of higher up holes that GM was so thoughtful in putting in the crossmember. This raised it roughly a half inch which brought my drive shaft angles to 5.5* down for the first and 0.5* up for the second. I took the opportunity to remove the shafts and see what it would look like if I flipped the carrier housing upside-down to see if I got better results. I can raise it much higher this way getting even better angles. I also got exact measurements off the tailshaft and pinion while the shafts were out. Those are both 5* down. So if I raise the carrier mount to the higher holes I end up with better but not great operating angles.

The confusion I'm having is that I've read on several places that the trans angle and pinion angle should be the same to cancel vibrations, also the operating angles should be less than 3*. Since my trans and pinion are the same, both down 5* then should I flip the carrier bearing mount, play with it until the operating angles are good and drill new holes? Or raise the trans up and shim the axle to keep the angles the same and see what that does to the drive shaft angles?

[garyd1961]

I always thought about a one piece driveshaft when setting pinion angles, never thought about a two piece shaft before. Not sure if the two piece simplifies it or complicates it. Sorry for not being able to help but I would be interested in how this turns out.

[67C10Step]

HO455's reference to the spicer link was what I was thinking when I was reading your post. I used that chasing some dive line vibrations in my son's Tacoma with a two piece drive shaft.

A much more advanced expert will probably chime in but I've always thought the transmission and pinion should be close to the same angle but could be on different planes. So, if your tranny is pointing down 6 degrees your pinion should be pointing up 5-7 degrees. The drive shaft(s) and u joints can make up the difference in height. As it is you have a 10.5 degree angle from output of tranny to pinon input and I don't think that is good.

[N9nefingers]

That makes a lot of sense to me. It's what I've been reading elsewhere as well. My question is...does that rule apply even with two piece shafts? If so I have a lot of parts to move around because I'm not close. I can't remember what the driveline angles were before I bagged the truck but I did have a whirring noise at around 50 mph and up. Just chalked it up to the carrier bearing. Maybe the driveline wasn't great before the bags.

[HO455]

Plugging your numbers into the calculator you come up with the angles that each ujoint is operating at. This is more important than the angle of the drivelines themselves. Measurement of the drivelines allows us to determine the angle the ujoint is operating at.
In a perfect world the ujoints would be between 1 degree and 3 degrees. The greater the angle you get less lifespan and the more vibration from the ujoint. Your set up is showing the following ujoint angles.
1.6*
8.6*
5.8*
Not exactly ideal. If you had a one piece set up a change of pinion angle would likely bring the angles into spec. With the 2 piece shaft a change in the pinon angle will increase the up angle of the 2nd shaft bringing the angle at the rear end into spec but making the center angle worse.
Ideally you would raise the pinon up and the carrier bearing mount up to get better angles. I'm assuming you have the pedestal mount carrier bearing and no slip joints in the drivelines. (Photo1) If that is the case moving the carrier up is more difficult, but it can be done.
Many folks do away with the carrier bearing and run a one piece set up. That has it's own issues as the length is so long it really requires a 3.5 inch diameter shaft that is of high quality with a superior balance to give trouble free service. Some driveline shops won't make such a shaft.
Another option would be to have the center ujoint replaced with a double cardone joint which won't have a problem with the large angle created by raising the pinon angle.
I suggest you jack the truck up and place jack stands under the rear axle (thus maintaining the ride height) and then unbolt the carrier bearing. With the bearing mount swung out of the way, find a way to support the bearing in a higher position and re-measure the angles to see if you can come up with better numbers.
I found that when I raised my pinion angle it made a larger change in the drive shaft angle than I expected. Here is a cut and paste from post 682 of my repair thread.
You will notice that there are only numbers for a one piece set up. I had converted to a1 piece due to a number of reasons not related to proper ujoint angles.
I am pretty sure your truck is lowered more than mine is. And with the addition of a gearvendors overdrive I have a much shorter driveline which is within the tolerances for a 3 inch drive shaft.

Once the driveline was installed I checked the U-joint angles. The one piece set up definitely changed the angles. The transmission angle didn't change, but the number I read did since I did the readings up on the jack stands this time.
The new number for the transmission is 2 degrees down.
The drive shaft was at zero degrees.
The pinon angle was at zero also.
Not the best arrangement. So I ordered a pair of 2 degree shims (Last photo) from Speedway Motors as there was nothing available locally.

https://www.speedwaymotors.com/Rear-...SABEgIe6PD_BwE

A couple days later I had them installed and once I had reset the bags to ride height and had double checked that the transmission number hadn't changed I checked the other angles.
Transmission angle 2 degrees down
Driveshaft angle 5 degrees up.
Pinion angle 2 degrees up.
I was surprised that the drive shaft angle changed so much with only 2 degrees of pinion change.
All this means the U-joint angles are now both 3 degrees. Just about perfect in my book.

I hope this helps I'm not an expert by any means but I have done some industrial driveline alignments in the past. And by all means ask if something isn't clear.

[SCOTI]

Originally Posted by N9nefingers

I need some help from driveline angle wizards...I've been reading and searching but the info I'm finding is either melting my brain or contains links that no longer work. Like this one... http://www2.dana.com/pdf/J3311-1-HVTSS.PDF ...which is a bummer because most threads point to this as the one to follow. I have a '70 C10 with a 350 and T350 with a two piece driveshaft. I have it on bags with Accuair Elevel set at ride height. Currently my driveline points down to the carrier bearing then up at the pinion. I'm thinking this is not correct as that's what I've been reading. But that info is for one piece driveshafts. Anybody got a good link or advice? Any and all help would be awesome.

Have you altered the carrier bearing mounting? If not & your truck is lowered, it needs to be raised if possible.

The Spicer info is spot-on for a non lowered vehicle where the rear end housing/pinion is well below the forward sections.

Once you start changing things, the most important thing to keep in mind is to try & set-up the driveline as straight as possible from the trans output to the pinion. As was mentioned, you need small differences between each section (called working angles) for the joints.

Also.... If the 1st shaft is pointing 'down' & the 2nd shaft is pointing 'up', the numbers are added together when calculating angles @ the joint between the two.

[N9nefingers]

Thank you for all the responses...I think I have a better idea of what I'm looking for now. I'm going into the garage to figure this out soon. I had earlier in the build gotten rid of the rivets holding the carrier bearing and trailing arm mounts in favor of grade 8 bolts knowing that I would bag the truck at some point. I think I'll try moving these around to see what the angles are. I'll post back with what I find. Thank you again for the responses.

[Ironangel]

Originally Posted by N9nefingers

Thank you for all the responses...I think I have a better idea of what I'm looking for now. I'm going into the garage to figure this out soon. I had earlier in the build gotten rid of the rivets holding the carrier bearing and trailing arm mounts in favor of grade 8 bolts knowing that I would bag the truck at some point. I think I'll try moving these around to see what the angles are. I'll post back with what I find. Thank you again for the responses.

Are you having a vibration problem? In other words, are you experiencing a problem or just tripping on shaft angles? If you have a C/10 with an unmolested rear axle (with coils & trailing arms) Axle in factory radial location, lowering your truck will lesson the critical angle which improves performance! All that other BS is out the window to that fact! Go ahead, ask me how I know? Anybody suggesting a one piece driveline either hasnt done one yet or dont understand the physics the GM engineers thankfully did! Get your drive line balanced and Slam that baby! Yer trippin! ~Ghostrider~

[Woodnears]

Fingers,
I can take a photo of how i set mine up if you would like. im running a full porterbuilt chassis with e-level. I had to fab up a 2" or so carrier bearing spacer to raise the bearing to achieve an acceptable driveline angle. Shoot me a PM with your number and i can text you as many photos as you need. Maybe it will help you imagine what needs to happen.

[N9nefingers]

Scoti when you're saying trans down and pinion up you are saying that the trans output physically points down and the pinion output physically points up towards the bed correct? But while the pinion output points up at the bed it is counted as a down angle correct?

[N9nefingers]

Woodnears I sent you a PM

[SCOTI]

Originally Posted by N9nefingers

Scoti when you're saying trans down and pinion up you are saying that the trans output physically points down and the pinion output physically points up towards the bed correct? But while the pinion output points up at the bed it is counted as a down angle correct?

Correct. In the orientation that is considered the standard, the pinion pointing up to the trans output is considered a 'down' angle. They are pointing toward each other.

[N9nefingers]

Update...I flipped the carrier bearing mount 180* and drilled holes/mounted it after moving it around for the best possible measurements. I played with moving the trans around as well. In the end the best I was able to get is 4.5* down for trans, 2.7* down for first shaft, 1.5* down for second shaft and 4.3* down for pinion. That leaves me with 1.8*, 1.2* and 2.8*. Thanks for all the help, info and advice you guys gave me.

[HO455]

Good work! It looks like you have got a nice good smooth set up.

I forgot where I had the link to this article stashed until this morning. I may not be of any use at this point but it does explain about ujoint lifespan versus angle.

https://4xshaft.com/blogs/general-te...onversion-kits

One more thing to check while you are at it, is the transmission yoke and how far it is sticking out past the end of the output shaft.
Since you have no sliding joint in the driveline all of the fore and aft movement is compensated with the yoke. Sometimes on lowered trucks there isn't enough room for the movement and the yoke bottoms out.
Sometimes tolerance stacking is your friend and other times it isn't.