pinon angle

pinon angle
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staceyronq

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All my rides? Well I have quite a few work trucks so I will leave them off. But I own a 79 cj5.
Does anybody know what the rear pinon angle is supposed to be on a CJ5 ? I have rebuilt mine and the Transmission seems to be a little high for some reason. The drive shaft going to the rear seems at a steep angle. Can anybody help me out.
 
Thanks. Hey do you know of a website or a book title that shows all angles, wiring, break lines, etc? I am looking for a complete jeep bible that shows the works of it all. I have a chiltons but that is just real generic.
 
Cheepjeep85 said:
a factory service manual would show you all of the info you want, there are some parts and pieces of them in the docs section, good info in there.
Click to expand...


Where is the docs section?
 
staceyronq said:
Does anybody know what the rear pinon angle is supposed to be on a CJ5 ? I have rebuilt mine and the Transmission seems to be a little high for some reason. The drive shaft going to the rear seems at a steep angle. Can anybody help me out.
Click to expand...

More info is needed on your set up before a ans or suggestion can be given. What tire size, what Transmission , mods to susepension.

Dave Woods Drive shafts has some very good info on drive lines. They know their stuff and similar suppliers are good ref.

I know the T-18 is a big Transmission and has a stock of 1" shim material to lower the Transmission so it clears the body/ does not hit. And it helps with the drive liine angle. I put in 3/4 or 7/8" on stock on mine and hit body on some larger bumps. I hear a bang and thinks its this clearance delta I did as example. Only use this as EXAMPLE because it may come into play with your set up too.


This is simple for guys that understand and is kinda a black art.... I am not the ans for you. but would like to know more and the resource guys at woods and etc will want to know more also.

If we are just doing 33" tires and doing some axle work or need to change the spring percehs. I read you can rotate the spring perch 5-6 degrees to help wiith the steep angle of drive line. For example,.... going with a early 70s Dana 44 and it needed spring perches.. First thing done to axle was have new spring perches welded on. I rotate them 5-6 deg. There are some nice lazer cut perches with 3 holes to move Forward/BAck 1" if need and the perch is 3x longer so it will help with axle wrap or wheel hop.

I have not looked or seen this info in the FSM so would like to see more of that too.


good luck
 
The pinion angle should match the angle of the output shaft of the TCase. The TCase may not be angled down much from the factory and the axle pinion shouldn't be angled up much either.
BusaDave9 said:
Let me add a couple notes on drive line angles.
If the U Joint angles on a drive shaft are not strait (they never are on an off road vehicle) then they actually speed up and slow down on each rotation. This can produce a bad vibration. But a drive shaft is made so the vibration of the front U Joint cancels the vibration of the rear U Joint. This works great if the the angle of the front U Joint to match the rear. This is how every manufacture makes vehicles.
degree2.gif
But this only works at small drive line angles. The UJoints don't like too much angle so when you lift your jeep you may have to angle the rear differential upward. This can be done with angled shims at the leaf springs. Then to keep both u Joint angles the same you can lower your TCase. If the drive line angles get to be too much you should then go to double cardan joint or a CV joint at the front of the drive shaft. A double cardan joint is 2 U Joints together.
0702_4wd_10_z+driveshaft_basics+new_driveshaft_installed.jpg

These 2 U Joints cancel each others vibrations. In that case the U Joint at the differential should not have any angle. To keep it from vibrating it should be strait like this.
degreecv.gif
Now you can see how the pinion is much higher than the manufacturer intended.
That vent reservoir is a good idea. Thanks for the tip.
Click to expand...
Check out this link: http://www.4xshaft.com/driveline101.html
 
Dave,

good stuff, well done!

Fred



PS
not here posters stuff to settle first.....
but my plan is the same locker combo you have on info to the <<< of your post. TrueTrac front and Ox rear. Some time would like to get your feedback and see if would do the same set up again. 44 rear & stock Dana 30 front with 33's pretty normal stuff.
 
I ended up cutting off my spring perches and shock mounts and twisting the rear axle up so it pointed right at the tcase.
 
hoerner7 said:
I ended up cutting off my spring perches and shock mounts and twisting the rear axle up so it pointed right at the tcase.
Click to expand...
if your differential pinion points directly to the TCase then you should be running a double cardan joint at the TCase.
05.gif

When a standard drive shaft is at an angle the U joint speeds up and slows down during each rotation.
degree2.gif
If both U Joint angles are the same as in the above picture then the U Joint at each end of the drive shaft will cancel each others vibrations.
If you ever take apart the slip joint of a drive shaft and put it together 90° from what the factory made it then it may look okay but the 2 u joints will increase each others vibrations.
As the name implies a CV joint (Constant Velocity Joint) always rotates at a constant velocity.
Check out these two links for a good explanation of how and why a U joint wont rotate a constant speed:
Universal joint - Wikipedia, the free encyclopedia
Universal_joint.gif


Constant-velocity joint - Wikipedia, the free encyclopedia
220px-Simple_CV_Joint_animated.gif
An improperly installed U Joint wont' vibrate like it's out of balance. It's a rotational vibration. Like the U Joint tries to speed up and slow down during each rotation.
UJoint1.png
 
Last edited:
Should be interesting. Neighbors welder did not like the 1/2" Dana 44 axle tube. Weld looked great but needed to remove one bacause rotate wrong way, spingover/under and on back of hitch rack get confusing.

After seeing the above... Wish I put under CJ to see where the transfer and axle pinion POINT.

Looks like if both horizontal... good.

If we rotate the pinion up, the Transmission / transfer should point more down the same amount. That right?

I pointed pinion up 5 deg and is what the perch mfg suggested. Will be fun to see if he was right. I have a T-18 with 3/4" of shims to lower Transmission like / similar to stock. Might be 5/8 got look. Stock is 1". So I might be adding more shims for between the skid plate and the frame to lower/point the Transmission /transf down.


I will guess summary..
1.. point up pinion and point down Transmission equal deg from horizontal.


2... If you can point the rear pinion directly at the Transmission /transf output..... this will work well, but a CV joint will need to be used at the Transmission /transfer

I hope to be lucky on this one....

Fred




I will be raising pinion up 5 deg from stock WELL ITS WELDED ALREADY, iF NEED will be Lowering T-18 with the frame/skid additional shims may tilt down Transmission 3 deg or so???

How many degrees can pinion & Transmission differ that it does not shake at hwy speed??
 
MN CJ7 said:
Looks like if both horizontal... good.

If we rotate the pinion up, the Transmission / transfer should point more down the same amount. That right?
Click to expand...
That's true up to a point. Factories make the Transmission /tcase horizontal if standard u-joints are used. When you install a lift the u-joints don't like the angles so you should angle the axle up but it's not so easy to angle the tcase down. Many lifted vehicles don't have these u-joints at the same angle. Bending a U-Joint at too high of an angle can be worse than the vibrations. Here's a u-joint that may help that.
off_set300x414.jpg

MN CJ7 said:
How many degrees can pinion & Transmission differ that it does not shake at hwy speed??
Click to expand...

That I don't have an answer to.
If you have more than a few inches of lift you are better off with a double cardan joint.
 
Thanks Dave,

mine is typical for CJ with 33" tires
2.5 spring lift
stock length HD shackles
1" body (should not be a factor)
33x12.5 tire
T-18 .... is odd ball... stock OEM uses 1" of shims between fram/skid
skid holds up T-18 . Resto work and there is 5/8 or 3/4 but less than
1" shims.


It worked fine prior, PO has a shim on rear axle. My new perches welded will be close to same. I est/guess the extra 3/8 of shims might lower or tilt 2-3 deg. It ran fine prior... could do 75 speed limit or more and did great.

Heck... I did not know the stock pinion is usually horizontal.


I guess, will find out in a couple of months when we thaw out.
 
I've done the differential angle chance but now the gear oil is pumping out the vent and it is a mess. Oil everywhere. If I lower the oil level the pinion will go dry. Any suggestions?
 
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