Caster over front pinion angle or front pinion angle over caster

Oh
bobthetj03 said:
Looks like at least a 1" drop with that box tubing stuffed in there, maybe 1.5". That's why I was asking if you were having troubles keeping 2nd and reverse from popping out.
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sorry didn't see the comment about the 2nd and reverse. To answer that I would say originally when I bought the jeep. I did not have an issue with 2nd and reverse. However on inspection I realized my inner boot on the shifter was completely tore out and the shift tower boot was also torn and in bad condition. Once I changed those and put the stiff outer rubber boot back on the shifter. I then had issues with 2nd staying in. I changed the rubber outer boot to a vinyl one made by a guy that makes them for jeep and it shifts like a dream now. I do have a little synchro grind from 1st to 2nd that is a separate issue but to answer your question. Once all of the proper boots were in I did have trouble with 2nd staying in but no longer have that issue with the new boot.
 
@EROCK, in the interim between removing the TC drop, adding SYE, and DC rear driveshaft. Adjust the rear pinon angle to match the TC output shaft angle, measure the driveshaft angle, then subtract the pinon angle from driveshaft angle. The remainder is the operating angle of the u joints. A severe operating angle will shorten u joint service life, and can potentially cause damage within the transfer case. In the table and graph below are limit recommendations from the stock u joint manufacturer, and the drawing on the right illustrates parallel output & input shafts.
spicer operating angle.jpgSpicer u joint life graph.jpgDrive Shaft drawing.jpg
Here's an example of how to use this information. Let's say the TC and pinion are at 7 degrees each, and the driveshaft is 14 degrees, subtract 7 from 14, which leaves a remainder of 7. Seven degrees is the operating angle of the u joint. Spicer recommends not exceeding 2500 rpm with a 7 degree u joint operating angle. There are variables, but keep it simple for the time being. With as much TC drop is on there now, I don't think the operating angle is going to be extraordinarily severe.

Take a picture of the engine mounts and share the images with us please.
 
k-huevo said:
@EROCK, in the interim between removing the TC drop, adding SYE, and DC rear driveshaft. Adjust the rear pinon angle to match the TC output shaft angle, measure the driveshaft angle, then subtract the pinon angle from driveshaft angle. The remainder is the operating angle of the u joints. A severe operating angle will shorten u joint service life, and can potentially cause damage within the transfer case. In the table and graph below are limit recommendations from the stock u joint manufacturer, and the drawing on the right illustrates parallel output & input shafts.
View attachment 73924View attachment 73925View attachment 73931
Here's an example of how to use this information. Let's say the TC and pinion are at 7 degrees each, and the driveshaft is 14 degrees, subtract 7 from 14, which leaves a remainder of 7. Seven degrees is the operating angle of the u joint. Spicer recommends not exceeding 2500 rpm with a 7 degree u joint operating angle. There are variables, but keep it simple for the time being. With as much TC drop is on there now, I don't think the operating angle is going to be extraordinarily severe.

Take a picture of the engine mounts and share the images with us please.
Click to expand...
k-huevo said:
@EROCK, in the interim between removing the TC drop, adding SYE, and DC rear driveshaft. Adjust the rear pinon angle to match the TC output shaft angle, measure the driveshaft angle, then subtract the pinon angle from driveshaft angle. The remainder is the operating angle of the u joints. A severe operating angle will shorten u joint service life, and can potentially cause damage within the transfer case. In the table and graph below are limit recommendations from the stock u joint manufacturer, and the drawing on the right illustrates parallel output & input shafts.
View attachment 73924View attachment 73925View attachment 73931
Here's an example of how to use this information. Let's say the TC and pinion are at 7 degrees each, and the driveshaft is 14 degrees, subtract 7 from 14, which leaves a remainder of 7. Seven degrees is the operating angle of the u joint. Spicer recommends not exceeding 2500 rpm with a 7 degree u joint operating angle. There are variables, but keep it simple for the time being. With as much TC drop is on there now, I don't think the operating angle is going to be extraordinarily severe.

Take a picture of the engine mounts and share the images with us please.
Click to expand...
Man! This is great info. I drove my Truck to work today. So I'll get a pic of motor mounts in the daylight tomorrow. I did take quick angle measurments on the Harmonic balancer and the rear diff last night. 81 degrees on the Harmonic Balancer and 77.8 degrees on the rear diff. That's perpendicular measurments of course and I know this doesn't matter really until I get them parallel and see what my drive shaft angle is.
 
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Do you guys recommend the rear diff being 1 degree lower than TC shaft so that on acceleration it lines up with the transfer case? I've read that in a few places.
 
EROCK said:
Do you guys recommend the rear diff being 1 degree lower than TC shaft so that on acceleration it lines up with the transfer case? I've read that in a few places.
Click to expand...
For a DC driveshaft a 1 - 2 degree drop is recommended.
 
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k-huevo said:
@EROCK, in the interim between removing the TC drop, adding SYE, and DC rear driveshaft. Adjust the rear pinon angle to match the TC output shaft angle, measure the driveshaft angle, then subtract the pinon angle from driveshaft angle. The remainder is the operating angle of the u joints. A severe operating angle will shorten u joint service life, and can potentially cause damage within the transfer case. In the table and graph below are limit recommendations from the stock u joint manufacturer, and the drawing on the right illustrates parallel output & input shafts.
View attachment 73924View attachment 73925View attachment 73931
Here's an example of how to use this information. Let's say the TC and pinion are at 7 degrees each, and the driveshaft is 14 degrees, subtract 7 from 14, which leaves a remainder of 7. Seven degrees is the operating angle of the u joint. Spicer recommends not exceeding 2500 rpm with a 7 degree u joint operating angle. There are variables, but keep it simple for the time being. With as much TC drop is on there now, I don't think the operating angle is going to be extraordinarily severe.

Take a picture of the engine mounts and share the images with us please.
Click to expand...
Any chance you can put a clearer pic of this diagram up. I can't read the numbers.
 
k-huevo said:
@EROCK, in the interim between removing the TC drop, adding SYE, and DC rear driveshaft. Adjust the rear pinon angle to match the TC output shaft angle, measure the driveshaft angle, then subtract the pinon angle from driveshaft angle. The remainder is the operating angle of the u joints. A severe operating angle will shorten u joint service life, and can potentially cause damage within the transfer case. In the table and graph below are limit recommendations from the stock u joint manufacturer, and the drawing on the right illustrates parallel output & input shafts.
View attachment 73924View attachment 73925View attachment 73931
Here's an example of how to use this information. Let's say the TC and pinion are at 7 degrees each, and the driveshaft is 14 degrees, subtract 7 from 14, which leaves a remainder of 7. Seven degrees is the operating angle of the u joint. Spicer recommends not exceeding 2500 rpm with a 7 degree u joint operating angle. There are variables, but keep it simple for the time being. With as much TC drop is on there now, I don't think the operating angle is going to be extraordinarily severe.

Take a picture of the engine mounts and share the images with us please.
Click to expand...

20190124_203316.jpg


20190124_203159.jpg
 
I adjusted the rear diff to be 1 degree below the TC. The following measurements are what I got.
Harmonic Balancer 7.5 degrees
Drive shaft 18.5 degrees
Rear Diff 6.5 degrees
Wierdly it now vibrates, it didn't before but now it does, especially under hard acceleration. I only drove it maybe a mile.

20190124_202416.jpg


20190124_202438.jpg


20190124_202516.jpg
 
EROCK said:
Any chance you can put a clearer pic of this diagram up. I can't read the numbers.
Click to expand...
Did you click on the image to expand?

Thanks for the engine mount pictures. I was curious to see if it had a riser beneath; it does not.
 
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EROCK said:
I adjusted the rear diff to be 1 degree below the TC...Wierdly it now vibrates...
Click to expand...
Raise the pinion 2 degrees and try again.

You need a digital gauge. :)

Rotate the output yoke so the u joint is vertical. Place a socket on the cap and measure again from the socket top.
 
k-huevo said:
Raise the pinion 2 degrees and try again.

You need a digital gauge. :)

Rotate the output yoke so the u joint is vertical. Place a socket on the cap and measure again from the socket top.
Click to expand...
Haha did I put the extra degree in the wrong way? So its suppose to be one degree up not down from the the TC line?
 
The goal now is to remove vibration. Put aside wrong or right absolutes, and find the sweet spot for your particular Jeep.
 
Better the pinion angle be 1 degree lower than the driveshaft angle than 1 degree above it. The pinion shaft angle raises a tad under acceleration so positioning it a degree low helps compensate for that.
 
Jerry Bransford said:
Better the pinion angle be 1 degree lower than the driveshaft angle than 1 degree above it. The pinion shaft angle raises a tad under acceleration so positioning it a degree low helps compensate for that.
Click to expand...
Did you mean the pinion angle needs to be 1 degree below the "TC Angle"? If its suppose to be 1 degree below the drive shaft angle, I just did everything wrong.
 
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