Please give me a crash course in axle shims

[RSchwarzli]

With the 5600 going into the 1990, I will need to shorten my driveshaft again.



Already with the 1" lift and the Gear Vendors, the rear shaft is at a good angle. I am worried with the much longer 5600 I will have a vibration.



Can someone therefore give me a rundown on axle shims. Who makes them, where do they go, how exactly do they work, etc?



I maybe able to make my own but I don't know much about them.



Thanks!

 

[NIsaacs]

If the shaft angle is okay now, the NV5600 addition should not change it if you keep the same engine/transmission angle you have now. The angle that matters is the degrees the transmission and rear axle is at, not so much as the drive shaft angle itself. If the transmission and rear axle are the same, the drive shaft angle will not matter. So... if you can, try not to raise or lower the center of the output shaft when you build the transmission or crossmember mount.



If you need axle shims, I think Summit has them. The best way is to center bolt them to the spring pack.



Nick

 

[S.Morris]

Check out Tom Woods driveshafts. There is a lot of good info on thier site and I have used them in the past to build one off 4x4 shafts.

The process was trouble free and the cost was 60% after shipping of what a local shaft builder wanted.

 

[Bob4x4]

As an FYI Tom woods has the front driveshaft fix for the lifted 4th gens with vibration issues

 

[cerberusiam]

If the shaft angle is okay now, the NV5600 addition should not change it if you keep the same engine/transmission angle you have now.

He already has a gear vendors hung on the back of the t-case plus a 1" lift and is now putting in a longer 5600. That is a LONG drive train in a reg cab frame.



Yeah, the angle is gonna get steeper but how much is too much varies. You can shim the rear axle only so much then you loose lube to the pinion bearings.



Think double cardan joints or a stretch job.

 

[DVolk]

You might check jack -its web site

 

[NIsaacs]

He already has a gear vendors hung on the back of the t-case plus a 1" lift and is now putting in a longer 5600. That is a LONG drive train in a reg cab frame.





Yup, and now the front shaft is gonna get even longer



Just to give an example, my original 1975 Ford 4x4 "Highboy" (regular cab/long bed) with the remote transfer case has a rear drive shaft of only 34" long. The actual drive shaft angle is steep. Just be sure and keep the same pinion angle as the transmission output shaft and you should be okay. If you tip the rear axle to lessen the drive shaft angle and get a mismatch of the pinion/transmission degrees you will get a mismatch of u-joint speeds and get vibration.



Nick

 

[JLEONARD]

The actual drive shaft angle is steep. Just be sure and keep the same pinion angle as the transmission output shaft and you should be okay. If you tip the rear axle to lessen the drive shaft angle and get a mismatch of the pinion/transmission degrees you will get a mismatch of u-joint speeds and get vibration.

Yes if you keep the angles the same there will not be vibration HOWEVER the steeper the angle the more load is on the pins and bearings hence it will wear quicker. Just something to be consious of.

 

[ENafziger]

To avoid vibration, you want the pinion angle and the output of the trans/xfer case/gear vendor to be at the same angle... or within 0. 5°. Obviously, the more vertical misalignment there is, the steeper the driveshaft angle will be; but, you shouldn't try to compensate for this by increasing the pinion angle. Does that make any sense???

--Eric

 

[cerberusiam]

Yup, and now the front shaft is gonna get even longer

Thats not as much an issue of functionality as it is expense. The cardan joint makes it usable and its generally not under drive power enough to matter a lot.

Yes if you keep the angles the same there will not be vibration

Thats not a given there will be no vibration. The wear will spread evenly though increased with angle, but, vibration has too many other factors to say positively there will be no vibration as long as angles match. Length, size, and construction will be much more critical at that point.



Basically, once you exceed 5-7 degrees of angle at each end you run the risk of vibration at some speed, and, severely reduce the ujoint life expectancy. For a truck that spends its time in playing at lower speeds its not an issue. You can run up to 14-15 degrees a lot of times and get away with it. Put it on the road at a constant speed over 40 mph and its almost a guarantee there will be vibration. How much it is noticeabe depends on the level of tolerance of the driver.



I have ridden in trucks that would drive me crazy in 100 miles with an incessant vibration\drone. The owner never noticed it because he was desensitized and had a higher level of tolerance.



The Ford Highboys were the WORST I have ever seen even brand new. They only got worse with age and a lot of it was drive shaft angles. Lack of isolation did not help either but thats all the old trucks.

 

[DVolk]

Just for curosity what gears do you have ? Does it now have the OD unit on it or do you just want to ad it ? My 92 with 355s dont need one how ever a half gear some times would be nice , i just drop a gear .

 

[RSchwarzli]

I am following along here. Just reading and learning everyone's thoughts.

Donovan

3. 07 and it is used for just that. Gear splitting. Not really for OD sake.


Eric

Yes making sense.


Cerb

All seems logical. Makes sense.


If I understand it all, I should be trying to correct the driveline vs just the diff. Got it.

Why I am so concerned on this is I developed a slight vibration after the lift and GV addition (same time installed) and the driveshaft co said it was borderline and might have one. I did in the end. So I am slightly paranoid.

 

[DVolk]

Maybe a constant volisity joint at one end or both , or bite my tongue may just change your gearing , in the axels with a 6 speed and 307s i dont think youd need it , just drop a gear when needed

 

[RSchwarzli]

Donovan

The higher gears actually make it worse than the lower. In the case of a 4. 10, you new the OD. Inthe case of the 3. 07, you need to split gears.

That's why the crew has 3. 55s.

I do want to leave the GV in it. And at this point I don't want to swap to 3. 55s ( will save that for the next mod when I break the D71! )


Ok. Will do a measure when it is in and see how bad it looks.

 

[DVolk]

I wish my crew had 355s i got 410s

 

[RSchwarzli]

Might I suggest you get a GV! :-laf

 

[DVolk]

I would if i can find one cheap then find a 32 spline one

 

[JDancoe]

FYI,
If you have access to a FSM, Pages 16-5 and 16-6 have a good explanation of driveline and U-joint angles. If you don't have a manual, you can get a CD version pretty cheap from Geno's. They also have a printed version but it's a lot more money. I actally have both.

I like the CD version. When I'm working in the shop, I can just print out the pages I need, put them in a sheet saver, and take them out with with me. Then I don't get greasy fingerprints all over it, like my paper manual has.

While we're on the subject of D/lines & U-joints, does anyone know where I can get the recessed grease fitting that are used in the C/V joint in the front D/line of a 4WD? The one that you grease with a pointed nozzle. I've asked in every auto parts store I've been in for the last 2 months, & nobody has them.
Jack Dancoe

 

[RSchwarzli]

Are you looking for the nipple or the tool?

And good point. I will check the FSM and see what it says. Good point.

 

[JDancoe]

B-

I have the tool. I need the nipple, or what I would call the cup.

I have installed a regular nipple type fitting, (like on a ball joint or tie rod)but to get the angle needed to get grease into the fitting I have to remove the driveshaft from the truck and put in a vise, grease it, and reinstall it.

Jack Dancoe