Drive line angle

[jakeh937]

Was looking at my rear drive line while I was under messing with my clutch linkage and noticed the angle seemed steep. It has a 2 inch lift on 33. The skid plate has spacers on it. I haven't noticed any vibration at 45-50. Just wondering what you guys think about it.. rear of Transfer Case
at rear axle


Sent from my iPhone using Tapatalk

 

[oldjeeplady]

My understanding is you really need the measure the angle and slope of your drive shaft, drive line to be sure. There is some very good information on the Tom Woods site on how to do this. If you enable the chome extension for photobucket, you can see some examples in our build threads. "They are coming to take me away, haha", and "One piece at a time." Bass is my husband.

Sent from the great Northwoods of Wisconsin using Tapatalk

 

[PistolDave]

Perhaps the angles in those pictures are misleading, but it appears that your pinion is pointed almost directly at the xfer case output yoke. If that is the case, you need to be running a double-cardan or CV style ujoint at the xfer case.


First picture is standard u-joint, second picture is CV style setup.

 

[jakeh937]

Perhaps the angles in those pictures are misleading, but it appears that your pinion is pointed almost directly at the xfer case output yoke. If that is the case, you need to be running a double-cardan or CV style ujoint at the xfer case.


First picture is standard u-joint, second picture is CV style setup.

For some reason I cannot see those pics. I will take a rough angle measurement tonight. You don't want the rear to be pointing at the Transfer Case ?



Sent from my iPhone using Tapatalk

 

[jp360cj]

For some reason I cannot see those pics. I will take a rough angle measurement tonight. You don't want the rear to be pointing at the Transfer Case ?



Sent from my iPhone using Tapatalk

With a single cardan shaft like you have (single joint on each end), you want the pinion to be parallel with the tcase output. This puts both u joints at the same operating angle. For a double cardan (cv) shaft, you want the pinion to point at the tcase output.

You'll need to measure 3 angles....pinion angle, driveshaft angle, and tcase output angle.

Here is some good info from Tom Woods:
Tom Wood's Custom Drive Shafts - Slopes VS Angles
Tom Wood's Custom Drive Shafts - Shaft Selection: CV or non-CV?

 

[Torxhead]

I would go with the CV joint like Pistol Dave suggested. The rear pinion looks like it is already setup for it but the driveshaft would have to be shortened to accept the cv joint. Then you would not have to lower the Transfer Case . I am surprised that you don't have any issues as is.

 

[jakeh937]

I would go with the CV joint like Pistol Dave suggested. The rear pinion looks like it is already setup for it but the driveshaft would have to be shortened to accept the cv joint. Then you would not have to lower the Transfer Case . I am surprised that you don't have any issues as is.

I will look into that. What issues will arise from the way it is? Also, I plan to get a rough angle measurement tonight. What's the max I should be at?



Sent from my iPhone using Tapatalk

 

[Torxhead]

I would think there has to be some vibration in there somewhere, which would cause excessive wear on the u-joints. Not sure how much you have the Transfer Case lowered, it will affect the clutch bellcrank geometry being like that.

 

[jakeh937]

I would think there has to be some vibration in there somewhere, which would cause excessive wear on the u-joints. Not sure how much you have the Transfer Case lowered, it will affect the clutch bellcrank geometry being like that.

That's what I thought but there is zero vibration up to 50. It's really smooth. The clutch linkage is doing some weird things but I think it's due in part from the 2" body lift the PO had. The driveline and clutch linkage are my 2 main concerns at the moment. I'll report back when I measure them tonight.


Sent from my iPhone using Tapatalk

 

[Torxhead]

A major player in the CJ clutch linkage is the bellcrank. I am pretty sure that the bellcrank is designed to be mounted perpendicular to the frame. This would balance the load to each of the pivots. Upsetting that can cause a pivot failure. Additions like body lifts and engine changes can affect this along with tired motor mounts. Although I do seem to be getting by with a 1" motor mount setup. There are two nylon bushings in the bellcrank that can wear out and should be replaced if necessary and it should be kept full of lube grease. That's the way I see it.

 

[jakeh937]

A major player in the CJ clutch linkage is the bellcrank. I am pretty sure that the bellcrank is designed to be mounted perpendicular to the frame. This would balance the load to each of the pivots. Upsetting that can cause a pivot failure. Additions like body lifts and engine changes can affect this along with tired motor mounts. Although I do seem to be getting by with a 1" motor mount setup. There are two nylon bushings in the bellcrank that can wear out and should be replaced if necessary and it should be kept full of lube grease. That's the way I see it.

That makes total sense. Found out the problem with the clutch. The bell housing piece that hold the fork ball has cracked and is missing a chunk off the end, allowing the ball to move in and out of the pocket on the fork. Now my question is this: is this normal? Or what has caused the bell housing piece to break?


Sent from my iPhone using Tapatalk

 

[jp360cj]

OP, do you have a CJ5 or CJ7 ? And which Transmission ?


Sent from my iPhone using Tapatalk

 

[jakeh937]

OP, do you have a CJ5 or CJ7 ? And which Transmission ?


Sent from my iPhone using Tapatalk

Mine is a 5 and it's the T-18


Sent from my iPhone using Tapatalk

 

[jp360cj]

OK, I thought your driveshaft looked a little steep for only a 2" lift.

How much of a tcase drop do you have? The T-18 is a tall Transmission and came from the factory with a 7/8" tcase drop. It used 7 1/8" plates stacked up. Even if you go with a double cardan shaft, you may not be able to remove the tcase drop.

With a single cardan shaft, the u joint operating angles should be under 15 degrees. Keep in mind that if you keep the single cardan shaft, you'll need to rotate the pinion Dien which will make your u joint angles work


Sent from my iPhone using Tapatalk

 

[jakeh937]

OK, I thought your driveshaft looked a little steep for only a 2" lift.

How much of a tcase drop do you have? The T-18 is a tall Transmission and came from the factory with a 7/8" tcase drop. It used 7 1/8" plates stacked up. Even if you go with a double cardan shaft, you may not be able to remove the tcase drop.

With a single cardan shaft, the u joint operating angles should be under 15 degrees. Keep in mind that if you keep the single cardan shaft, you'll need to rotate the pinion Dien which will make your u joint angles work


Sent from my iPhone using Tapatalk

So right now my tcase drop is I attempted to measure my angle and I believe coming from the tcase is about 20* and off the rear axle is about 17*


Sent from my iPhone using Tapatalk

 

[jp360cj]

I attempted to measure my angle and I believe coming from the tcase is about 20* and off the rear axle is about 17*

That's not the factory tcase drop, but it's close to the same size.

Are those angle the operating angles of the u joints, or just the angle of the driveshaft or what? The operating angle of u joints would be the driveshaft angle + or - the pinion/tcase output angle (the + or - depends on the direction). There is more than a 3* difference between those 2 u joint angles. For example, on my double cardan rear shaft, the tcase output is 5* down and the driveshaft is 20* down, so the operating angle is 20-5=15*. On the axle end, the pinion is 18* up and the driveshaft is 20* up, so that u joint angle is 2*.

edit: if you front joint really is operating at 20*, then you are well beyond the 15* limit that Tom Woods recommends for a single cardan shaft. If you don't have vibrations and binding, then at the very least the joints won't last very long.

 

[jakeh937]

That's not the factory tcase drop, but it's close to the same size.



Are those angle the operating angles of the u joints, or just the angle of the driveshaft or what? The operating angle of u joints would be the driveshaft angle + or - the pinion/tcase output angle (the + or - depends on the direction). There is more than a 3* difference between those 2 u joint angles. For example, on my double cardan rear shaft, the tcase output is 5* down and the driveshaft is 20* down, so the operating angle is 20-5=15*. On the axle end, the pinion is 18* up and the driveshaft is 20* up, so that u joint angle is 2*.



edit: if you front joint really is operating at 20*, then you are well beyond the 15* limit that Tom Woods recommends for a single cardan shaft. If you don't have vibrations and binding, then at the very least the joints won't last very long.

So I measured again.. here's what I came up with. I'm still lost on what I have or what I need to do.

Rear pinion angle- 16*
Driveshaft itself - 22*
Tcase(measured off the Transmission oil pan) 8*




Sent from my iPhone using Tapatalk

 

[jp360cj]

So I measured again.. here's what I came up with. I'm still lost on what I have or what I need to do.

Rear pinion angle- 16*
Driveshaft itself - 22*
Tcase(measured off the Transmission oil pan) 8*

Your operating angle at the tcase is 14* (22 for the driveshaft - 8 for the tcase). This is pretty much the limit for a single cardan at highway speed. IMO, the best long term solution is going to be a double cardan (aka "DC" or "CV") shaft. From the pics, your shaft looks like it's already a larger aftermarket shaft. If you have a driveshaft builder near you, you might can take your shaft to them and had the DC put on it (instead of buying a whole new shaft). But I would get a price on the job first; you can get a new shaft for ~$250ish and sometimes the rework of an old shaft costs more than the parts for the new one. You will also need a new yoke on the Transfer Case because the bolt hole are slightly different spacing on the DC. You will then need to shim your rear axle to get the operating angle down to 1-2* on that end.

The operating angle at the rear axle is 6*. Ideally with a single cardan shaft, the u joints should be at the same operating angle. If you make your rear angle match the front, the pinion will be lower and the angle of both joints will end up over the 14* the front angle is now.

Honestly, if you aren't getting any vibrations, then I would put it on the list of things to do, but it doesn't have to be done immediately. The main purpose of the DC shaft is to eliminate/prevent vibration. However, if you remove the tcase drop like you mentioned in one of your threads, then the driveshaft will need to be addressed sooner.

 

[jakeh937]

Your operating angle at the tcase is 14* (22 for the driveshaft - 8 for the tcase). This is pretty much the limit for a single cardan at highway speed. IMO, the best long term solution is going to be a double cardan (aka "DC" or "CV") shaft. From the pics, your shaft looks like it's already a larger aftermarket shaft. If you have a driveshaft builder near you, you might can take your shaft to them and had the DC put on it (instead of buying a whole new shaft). But I would get a price on the job first; you can get a new shaft for ~$250ish and sometimes the rework of an old shaft costs more than the parts for the new one. You will also need a new yoke on the Transfer Case because the bolt hole are slightly different spacing on the DC. You will then need to shim your rear axle to get the operating angle down to 1-2* on that end.



The operating angle at the rear axle is 6*. Ideally with a single cardan shaft, the u joints should be at the same operating angle. If you make your rear angle match the front, the pinion will be lower and the angle of both joints will end up over the 14* the front angle is now.



Honestly, if you aren't getting any vibrations, then I would put it on the list of things to do, but it doesn't have to be done immediately. The main purpose of the DC shaft is to eliminate/prevent vibration. However, if you remove the tcase drop like you mentioned in one of your threads, then the driveshaft will need to be addressed sooner.

Okay that makes more sense. Will I be going through u joints quickly how I have it now?

I have a rebuilt tcase that I did and bought a different rear output yoke for a D.C. when I had my original plan with a build.

As far as shims go I'm not to sure if the rear is already shimmed or not. I'm assuming it is being it looks titled up as it sits. If that's the case, am I better taking it somewhere and having them cut the perches, rotate the axle up and re-weld them on? Also as far as getting rid of the tcase drop, does that put more stress on the motor mounts? Or is it really as simple as just watching the fan and jacking the skid plate up?


Sent from my iPhone using Tapatalk

 

[jp360cj]

Okay that makes more sense. Will I be going through u joints quickly how I have it now?

I have a rebuilt tcase that I did and bought a different rear output yoke for a D.C. when I had my original plan with a build.

As far as shims go I'm not to sure if the rear is already shimmed or not. I'm assuming it is being it looks titled up as it sits. If that's the case, am I better taking it somewhere and having them cut the perches, rotate the axle up and re-weld them on? Also as far as getting rid of the tcase drop, does that put more stress on the motor mounts? Or is it really as simple as just watching the fan and jacking the skid plate up?

I'm really not sure how long the u joints will last. I know the higher the angle the shorter the life, but that's about all I know.

Is the other tcase also a Dana 20 ? 2 different rear output shafts were used on the Dana 20 . I don't remember the spline count, but one was a coarse spline (around 10 i think) and the other was a fine spline (around 26/27). You'll have to check the splines to see if the DC yoke will work for your tcase. Or if the rebuilt one is a Dana 20 , you could just use that tcase.

As far as the rear, yes, cutting the perches and rewelding them would actually be preferred over using shims, especially large ones. If you go this route, I would remove any current shims and just have the perches set correctly.