Jeep Wrangler Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
142 Posts
Discussion Starter #1
Hi all, I need some help...I just finished the install for a SOA lift on a 95 Wrangler. I crawled under and was looking at the axle pinion angle and measuring it out, and I will have to go with 32-33* shims to get the axle pinion pointing at the TC output pinion.

(This is a bolt on kit and the stock perches were re-used and were not removed or repositioned)

I have stock springs with a Rancho add a leaf of 2" in the spring pack, however the add a leaf was added in 1996 and I believe has sagged since. I did before and after measurements and net amount of lift for me from this kit was 5.5".

On a separate measurement, the distance from yoke to yoke is 22 3/4" and the drop from the TC output pinion yoke to the axle yoke is 11 1/2".

I'm running Stock shackles as well, and I do not have (and would very much like to avoid) a transfer case drop.

Is the 32-33 degree angle excessive for this? If I have to shim the axle this much is there other considerations when doing a shim this much?

Does anyone know what might be needed to fix/adjust this?

Thanks....
 

·
Registered
Joined
·
4,885 Posts
Probably going to get a better answer in the YJ thread...

good luck none the less :)
 

·
Registered
Joined
·
2,933 Posts
With an SOA you do not point the yoke at the TC output. If you have a Traction Bar you point it about 2-3 degrees low. If you have no traction bar you need to point it more around 6 degrees low.

I dont know if you know what axle wrap is, or how much homework you did before installing the kit, but that is the biggest part of doing an SOA properly. When you hit the gas your axle is going to twist your rear springs and the yoke will rise. When it is under power is when it needs to point directly at the yoke (assuming you are doing a CV shaft). If you have a traction bar it will not rise anywhere near as much which is why you reduce the angle to compensate for the difference.

Personally I have a CV shaft. I do not like it, it is nt very durable and I have to grease it all of the time. I am assuming you got an SYE? If you did not get one yet then I would suggest a super short SYE with 1350 joints and a strait shaft that has a slip. The larger joints will handle the steep driveshaft angle, and the driveshaft is much more durable. You would also make your axle yoke parallel (under power) with the TC output. I am guessing you probably looked into this a little bit. If you didnt just google YJ axle wrap. There are some good videos showing exactly what it is.

Also, you should either add a full length leaf to those spring packs, or get the rubicon spring packs made for SOA. Either of those will help quite a bit with axle wrap whether you have a traction bar or not, but I highly recommend a traction bar.
 

·
Registered
Joined
·
142 Posts
Discussion Starter #5
With an SOA you do not point the yoke at the TC output. If you have a Traction Bar you point it about 2-3 degrees low. If you have no traction bar you need to point it more around 6 degrees low.

I dont know if you know what axle wrap is, or how much homework you did before installing the kit, but that is the biggest part of doing an SOA properly. When you hit the gas your axle is going to twist your rear springs and the yoke will rise. When it is under power is when it needs to point directly at the yoke (assuming you are doing a CV shaft). If you have a traction bar it will not rise anywhere near as much which is why you reduce the angle to compensate for the difference.

Personally I have a CV shaft. I do not like it, it is nt very durable and I have to grease it all of the time. I am assuming you got an SYE? If you did not get one yet then I would suggest a super short SYE with 1350 joints and a strait shaft that has a slip. The larger joints will handle the steep driveshaft angle, and the driveshaft is much more durable. You would also make your axle yoke parallel (under power) with the TC output. I am guessing you probably looked into this a little bit. If you didnt just google YJ axle wrap. There are some good videos showing exactly what it is.

Also, you should either add a full length leaf to those spring packs, or get the rubicon spring packs made for SOA. Either of those will help quite a bit with axle wrap whether you have a traction bar or not, but I highly recommend a traction bar.
Got back under the heep and measured the TC output angle, it is 7*, and the axle pinion angle is also 7*, the 33* I measured earlier was the driveline slope. Now I just have to figure out how to crunch these #'s to get a correct driveline angle.

From what I have read if I use a double cardan CV I have to point the axle pinion at the TC??? But I'm new at all this driveline stuff...I noticed you mentioned a straight shaft with a slip, being fairly new to this driveline verbiage, is that a CV? I know there is a guy on here (Ibuildembig) which dosen't run a cv driveline, from all the talk on this site a double cardan cv is the only driveline out there? I am running a Tera Flex extreme short shaft SYE, and with that it only gave me room for a 23" rear driveline...

I am familiar with axle wrap, and I looked at anti-wrap kits etc, but decided to wait on this issue until after the kit was fully installed for 2 reasons, I have in the spring pack an add a leaf of 2.5 inches (which has sagged over the years) and according to this kit the way the perches are setup an anti wrap is not needed (we will see on this one) with both of these mitigating the axle wrap issue I decided to wait, if I do see signs of wrap I can always install a kit then.

More research I guess before I get this thing wrapped up...
 

·
Registered
Joined
·
2,933 Posts
Yeah I have long perches to. Still need to address axle wrap.

The driveshaft I am talking about is non cv. Cv shafts are a pain in the ass.
 

·
Registered
Joined
·
142 Posts
Discussion Starter #7
OK, would like to get some feedback on these thoughts...

Situation, 6" SOA lift and a SYE kit, no TC drop kit and no shims (yet) which gives me according to my calculations/measurements, (22.5" long by 11" drop)
TC output yoke 7* down angle, driveline slop 32*, and pinion angle 7* down. Results give me 25* working angle.

After a little more research I have found that I have 3 options....

1. Go with a standard U-joint (single cardan) style since the TC output and pinion angles are parallel and within 3* of each other, and not shim or drop TC, but I would be dealing with a 25* working angle and I'm not sure if I could find a driveline to handle that angle???

2. Go with a standard (single) cardan and do a TC drop of 1 inch, (should correct for 4* of angle), a modest shim to keep the pinion in parallel and within 3* of the TC, and this could drop my working angle to hopefully below 21*. With this # I could use a 1310 with a max angle of 30*

3. Go with a double cardan (CV) driveline, however I would have to go with a large shim, and the largest I have found/recommended was 21*. I really do not want to shim it this much, other problems usually ensue from this, I'm also aware that as I shim the rear, the driveline slope changes (decreases) and thus the working angle decreases, and I may not need as aggressive shim as 21*????

Also I'm aware of the 2-3* angle needed for under power, which helps me in this situation, so if I applied that to my 21* I would actually need a 18-19* shim...

So am I over thinking this problem? Should I just get a shim made that will point the driveline at the TC slap it in and call it a day? Or???

Any input would be welcome at this point...

Thx
Ben
 

·
Registered
Joined
·
2,933 Posts
Put in 1350 joints and a strait shaft, no cv.
 

·
Registered
Joined
·
2,933 Posts
To be honest, I would rather drop the TC 1" then run a CV shaft. According to Ibuildembig you do not need to drop TC though on a regular SOA. I do know the max angle on a driveshaft is supposed to be roughly 15 degrees. The bigger your UJoints the steeper angle they will handle though. You could always go to 1410 too. Obviously shims ar very important to make sure you get the correct geometry though.
 

·
Registered
Joined
·
142 Posts
Discussion Starter #10
To be honest, I would rather drop the TC 1" then run a CV shaft. According to Ibuildembig you do not need to drop TC though on a regular SOA. I do know the max angle on a driveshaft is supposed to be roughly 15 degrees. The bigger your UJoints the steeper angle they will handle though. You could always go to 1410 too. Obviously shims ar very important to make sure you get the correct geometry though.
I was kind of leaning towards this, going with 1410's that have around 37* max angle. If I were closer to 15* on my working angle I would just go with a non cv and slap in some 1310 which have a 30* max working angle, but at 26*, even if I take out the 2-6* for under power conditions I'm still over the 15* (half of max angle) that is recommended.
 
1 - 10 of 10 Posts
Top