Dynatrac PR 60 install questions ? Please help

[Deacon]

Ok, so Ive posted in a few other threads , so I thought Id start my own.
For some reason I just cant grasp the whole pinion angle - caster relationship and I have read the various threads here and on other forums as well as watched videos etc. First time doing an axle swap and starting from scratch. My past 2 jeeps I got close on the measurements and then had it aligned then came back and made adjustments like everyone has recommended and all was well.

Buster3479 stated in this link "Rear driveshaft angle. I was able to set the rear axle pinion pointed directly at my xfer case so that the 1350 shaft I used has a 0 degree change at the pinion end. It's just under the maximum angle Dynatrac specified on the hang tag they provided."

So do I point the pinion at the transfer case as in straight line or point at transfer case with the pinion at 0 degrees on the flange.
In this picture my Rear upper is set to 17 3/4"( stock at 17 7/16 ) and Rear lower at 20" ( stock 19 3/4) - Bump stops are now centered.
When I have my angle finder at ride height (no coils) it shows 77 degrees at the pinion flange - What should it read ?


Can someone please advise on if this is right or what I need to do to get it right.. thanks in advance

 

[Jkzinger]

I got mine close using a straight edge to the transfer case then installed the driveshaft then adjusted the pinion angle exactly straight with the shaft.


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[Speedy_RCW]

Ok, so Ive posted in a few other threads , so I thought Id start my own.
For some reason I just cant grasp the whole pinion angle - caster relationship and I have read the various threads here and on other forums as well as watched videos etc. First time doing an axle swap and starting from scratch. My past 2 jeeps I got close on the measurements and then had it aligned then came back and made adjustments like everyone has recommended and all was well.

Buster3479 stated in this link "Rear driveshaft angle. I was able to set the rear axle pinion pointed directly at my xfer case so that the 1350 shaft I used has a 0 degree change at the pinion end. It's just under the maximum angle Dynatrac specified on the hang tag they provided."

So do I point the pinion at the transfer case as in straight line or point at transfer case with the pinion at 0 degrees on the flange.
In this picture my Rear upper is set to 17 3/4"( stock at 17 7/16 ) and Rear lower at 20" ( stock 19 3/4) - Bump stops are now centerded.
When I have my angle finder at ride height (no coils) it shows 77 degrees .
View attachment 282926

Can someone please advise on if this is right or what I need to do to get it right.. thanks in advance

You want the pinion face perpendicular to the driveshaft. I’m a little confused by your post because it sounds like you already have it correct. If your driveshaft is at a 10 degree angle you want you pinion to read 80 or 100 depending on how you’re measuring.

Edit: guess I misread. It was Buster that had it right. My point still applies though. Hope it makes sense.
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[WJCO]

Assuming we are talking about the rear axle only: You're overthinking it. Ditch the angle finder and don't worry about caster. Just make sure pinion and driveshaft point at each other. I've found it's easier to snap a picture of it, then go on your computer with a photo software and draw lines through both parts. If you did it right, they should overlap each other identically. Truthfully, you should be able to see this on the jeep visually regardless.

My tablet has shitty editing, but in pic below, the lines point at each other. That's basically what you want.

 

[Buster3479]

Deacon - Basically what WJCO said, I first set a straight line at the axle end (by the way, I never thought to use a picture, that's brilliant WJCO).

Then for a sanity check, I checked the angle to make sure it was under what Dynatrac specified on their hang tag. In order to do so, I held a socket up to the end of the yoke that the strap fits around, made sure the yoke was rotated up and down (eyeballed it), and then measured an angle finder off the socket.

I'll take a picture later on if you need, I'm on 4 jackstands and not at ride height at the moment, so you'll have to disregard the number. If it's confusing I can post a picture just for clarification on how I spot checked it with the driveshaft in place.

 

[Deacon]

Assuming we are talking about the rear axle only: You're overthinking it. Ditch the angle finder and don't worry about caster. Just make sure pinion and driveshaft point at each other. I've found it's easier to snap a picture of it, then go on your computer with a photo software and draw lines through both parts. If you did it right, they should overlap each other identically. Truthfully, you should be able to see this on the jeep visually regardless.

Thanks that really helped, yes I was talking about the rear only and yes I was overthinking it

Deacon - Basically what WJCO said, I first set a straight line at the axle end (by the way, I never thought to use a picture, that's brilliant WJCO).

Then for a sanity check, I checked the angle to make sure it was under what Dynatrac specified on their hang tag. In order to do so, I held a socket up to the end of the yoke that the strap fits around, made sure the yoke was rotated up and down (eyeballed it), and then measured an angle finder off the socket.

I'll take a picture later on if you need, I'm on 4 jackstands and not at ride height at the moment, so you'll have to disregard the number. If it's confusing I can post a picture just for clarification on how I spot checked it with the driveshaft in place.

Thanks for the input - BTW , my axles didnt have a hang tag specifying anything about pinion angle, but I read it multiple times throughout the Dynatrac 60 postings.

I still dont understand what it means by 0 pinion angle - by chance can you explain in simple terms - what should my reading be at the yoke - is there a set degree number ?


Also - thanks to all for the input - My rear axle is in , tires on and starting the front axle swap tonight - the rear wasnt bad but after 2 days of getting up and down in my house garage - bodys a little sore -

 

[WJCO]

Thanks that really helped, yes I was talking about the rear only and yes I was overthinking it.

Thanks for the input - BTW , my axles didnt have a hang tag specifying anything about pinion angle, but I read it multiple times throughout the Dynatrac 60 postings.

I still dont understand what it means by 0 pinion angle - by chance can you explain in simple terms - what should my reading be at the yoke - is there a set degree number ?


Also - thanks to all for the input - My rear axle is in , tires on and starting the front axle swap tonight - the rear wasnt bad but after 2 days of getting up and down in my house garage - bodys a little sore -

Glad to help. Not sure where your '0 pinion angle' question came from. Maybe you mean 0 degrees of change, which is ideal for the rear. Every vehicle is different, so there really isn't a set number that it should be at.

Now on the front, technically, you would also want a 0 degree change between pinion and driveshaft, but that's near impossible to accomplish without causing a shitty caster angle which would cause steering wander. This is why the factor recommends 4.2 (to balance the two angles) and why Dynatrac builds even more caster into the axle to optimize both caster and pinion angle. When you do your front, just set the axle up with the caster that Dynatrac recommends (I think it's 6) and do not worry about the driveshaft angle. If you get vibrations after you test drive it, you can address it at that time.

The DIY alignment link should help you set the caster, and below is a picture that Dynatrac provides explaining a little of how Jeep and Dynatrac build their axles (this is a picture from a PR44, but same idea).

https://wayalife.com/showthread.php...nt-End-Alignment?p=42391&viewfull=1#post42391