How many have had their driveshafts balanced?

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tennmogger

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Specifics might be better than a poll. Checked out my driveshafts, found 2 of 4 u-joints with a little side play, replaced same. That made a noticeable difference in shaft vibes. Measured hinging angles: one was 7 thou, one 11 thou, with 20 thou (if I recall) permitted. Called it good. No balancing done.
 

coachgeo

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Specifics might be better than a poll. Checked out my driveshafts, found 2 of 4 u-joints with a little side play, replaced same. That made a noticeable difference in shaft vibes. Measured hinging angles: one was 7 thou, one 11 thou, with 20 thou (if I recall) permitted. Called it good. No balancing done.
good idea...... have created poll....... at https://www.steelsoldiers.com/showthread.php?192116-How-many-have-had-their-driveshafts-balanced-THE-POLL

but both threads can complement each other
 

simp5782

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All drivelines are balanced or made as a matched pair when built. Sometimes the parts are weighted right and do not need weights but ground to match. Others add weights. Any driveline shop will balance a shaft as standard building.

Unless the shaft threw a weight, was struck by something, or replacing slip yokes or welding on new yokes it does not need to be balanced. Some military shafts are put together out of phase which can cause a vibration.

Out of balance or bent drivelines cause high speed vibrations with or wothout throttle application. Light throttle application vibrations are from bad u joints or slip yokes. They then go away with more throttle or no throttle at all. Secondary check is to shake em for play by hand.

Videos of out of balance drivelines attached. Notice the movement. You will feel it easy enough if its out of balance.

https://youtu.be/QqAavTudMB8

https://youtu.be/nWtabgRvepU
 

coachgeo

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So piggy backing on Tennmoggers idea.... have completed poll in other thread. Now here is my details so far on Ol' Rusty

rear shaft was fully custom made with all new parts and balanced.... since other one wobbled free and destroyed my tranny. Since then it has been shortened slightly and rebelanced to accommodate the 6x6 middle axle as my only rear axle. this custom install brings rear driveline up to near horizontal. why did this??.

1. to keep it better out of harm's way when off road.. YET if something does happen to it (nick/dent shaft orr??).... a drive home or to a nearby shop is less liable to allow for vibrations to transfer thru to other components and cause catastrophic damage as a happened to me previously. (drive shaft physics says more drive shaft angle... more vibrations are transferred.... less angle / less transfer)

2. military switched to same design later on.... though I do not know their reasons... might be same as mine???. might be something else?? but figured their engineers know more than my feeble brain so I copied them
 
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coachgeo

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Specifics might be better than a poll. Checked out my driveshafts, found 2 of 4 u-joints with a little side play, replaced same. That made a noticeable difference in shaft vibes. Measured hinging angles: one was 7 thou, one 11 thou, with 20 thou (if I recall) permitted. Called it good. No balancing done.
thanks..... so your poll click would be

FRONT custom/rebuilt post truck purchase install NOT BALANCED
and
REAR custom/rebuilt post truck purchase install NOT BALANCED

 
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Fallon, NV
My M1081 had the supposed modified drive shafts. Ran fine down the road but I wasn't convinced all was well. When I bought the truck, the bolts on the bracket between the air compressor and the power steering pump were missing, as were the bolts for the alternator. Less than 12,000 miles on the odometer.
Fast forward several years, I pulled both shafts, dropped them at a truck driveline rebuild shop. Both shafts had badly worn splines, the front worse than the rear. Both shafts were completely rebuilt, and it's like night and day, the noise and vibration difference is huge from before to after.
I'm not sure that my drive from Colorado Springs, CO to Fallon, NV would have been as successful or comfortable without the rebuild.
 

cucvmule

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Very nice short video's of wear tolerance, balance problem that becomes a huge problem.

Most times the problem has a preventative measure that has been overlooked. Mounting hardware, rubber isolators, rubber mounts or lubrication joints, overlooked or missing grease fittings. and can not be lubricated. Sealed bearings that can not be lubricated, when they go bad they go bad fast.

Then there are normal wear patterns that have to be inspected by schedule or when known, sooner.

Assembly of components even when all are in new condition is very critical to check for proper assembly, after repair. I check my driveshafts on equipment at every oil change and grease joints at the same time, or daily depending on the machine. But the sealed joints cause me the most apprehension.

On large trucks, equipment the forces involved pushing, pulling, rotational, centrifugal force, driveline vibration, u-joints are under such strain it is a wonder that they hold together at all.
 

Reworked LMTV

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So we should jack up the back of the truck and watch for movement? I also note that it is recommended that the Ujoints have safety straps, but my search has come up empty. Would loctiite work?
All drivelines are balanced or made as a matched pair when built. Sometimes the parts are weighted right and do not need weights but ground to match. Others add weights. Any driveline shop will balance a shaft as standard building.

Unless the shaft threw a weight, was struck by something, or replacing slip yokes or welding on new yokes it does not need to be balanced. Some military shafts are put together out of phase which can cause a vibration.

Out of balance or bent drivelines cause high speed vibrations with or wothout throttle application. Light throttle application vibrations are from bad u joints or slip yokes. They then go away with more throttle or no throttle at all. Secondary check is to shake em for play by hand.

Videos of out of balance drivelines attached. Notice the movement. You will feel it easy enough if its out of balance.

https://youtu.be/QqAavTudMB8

https://youtu.be/nWtabgRvepU
 
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simp5782

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Some u joint suppliers include them. Some don't. They are not requited at all. Spicer and meritor do not include them in their u joint kits. The bolts come with their recommended locktite on them. If the 2 biggest distributors of driveline parts do not include them as a replacement with their kits then they are not necessarily. I have ran drivelines with and without the little straps. If you have a vibration the straps and the bolts will snap. Simple as that.

In my opinion they are not necessary. Lock tite will secure the bolts good enough.

Your choice color or blue, red, or green loctite is on you. I personally use green cause i don't want any bolt coming off.


You will feel an out of balance driveline by driving. Checking slack in the yokes and joints can be done on the ground. If you have an out of balance driveline it will wear the slip yoke out in less than 500 miles. So the slip yoke replacement will result in the driveline being balanced any way
 
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Awesomeness

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Some u joint suppliers include them. Some don't. They are not requited at all. Spicer and meritor do not include them in their u joint kits. The bolts come with their recommended locktite on them. If the 2 biggest distributors of driveline parts do not include them as a replacement with their kits then they are not necessarily. I have ran drivelines with and without the little straps. If you have a vibration the straps and the bolts will snap. Simple as that.

In my opinion they are not necessary. Lock tite will secure the bolts good enough.

Your choice color or blue, red, or green loctite is on you. I personally use green cause i don't want any bolt coming off.


You will feel an out of balance driveline by driving. Checking slack in the yokes and joints can be done on the ground. If you have an out of balance driveline it will wear the slip yoke out in less than 500 miles. So the slip yoke replacement will result in the driveline being balanced any way
I disagree with a lot said here.

1.) My Spicer u-joints did come with the tab washers. Clearly some don't, but if some do, Spicer must not think they are a bad idea. The part number for them separately is Spicer 98-741 ("lockstrap").

2.) Loctite does work pretty well, but tab washers generally work better. Where you really don't want to use Loctite is high heat environments (over about 300°F). If you're not planning to take them on and off a lot, the tab washers are a better option. When you install them, only bend up one ear/tab, and save the other for a future installation. Using Loctite does mean that you can basically never turn the screws freely by hand again - they will have just enough resistance that you will forever need a wrench/ratchet.

3.) Green Loctite is wicking, meaning you can put it on after the fasteners are installed, and it will hopefully wick into the joint with capillary action. It (green) has nothing to do with the strength, and is the same as medium strength Loctite (blue). High strength (red) is expected to be heated (300°F) in order to be removed, though usually you can get it off with a lot of force and no heat. In experiments we've done at work, the wicking (green) Loctite does not wick into threads reliably, even on just a nut and bolt, and is worse on bolt in a hole.

4.) I couldn't feel it when my driveshaft was out of balance (and it destroyed the engine). I couldn't feel the change once I had them balanced either. Clearly the history of FMTV's destroying engines and transmissions due to driveline vibrations demonstrates that lots of people couldn't tell. I would not count on being able to tell, or you might have some costly repairs.
 
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simp5782

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I disagree with a lot said here.

1.) My Spicer u-joints did come with the tab washers. Clearly some don't, but if some do, Spicer must not think they are a bad idea. The part number for them separately is Spicer 98-741 ("lockstrap").

2.) Loctite does work pretty well, but tab washers generally work better. Where you really don't want to use Loctite is high heat environments (over about 300°F). If you're not planning to take them on and off a lot, the tab washers are a better option. When you install them, only bend up one ear/tab, and save the other for a future installation. Using Loctite does mean that you can basically never turn the screws freely by hand again - they will have just enough resistance that you will forever need a wrench/ratchet.

3.) Green Loctite is wicking, meaning you can put it on after the fasteners are installed, and it will hopefully wick into the joint with capillary action. It (green) has nothing to do with the strength, and is the same as medium strength Loctite (blue). High strength (red) is expected to be heated (300°F) in order to be removed, though usually you can get it off with a lot of force and no heat. In experiments we've done at work, the wicking (green) Loctite does not wick into threads reliably, even on just a nut and bolt, and is worse on bolt in a hole.

4.) I couldn't feel it when my driveshaft was out of balance (and it destroyed the engine). I couldn't feel the change once I had them balanced either. Clearly the history of FMTV's destroying engines and transmissions due to driveline vibrations demonstrates that lots of people couldn't tell. I would not count on being able to tell, or you might have some costly repairs.
Sleeve retainer is rated at 3000psi just as red loctite. It actually works better at filling in the gaps. It has
to be removed with heat as well.

If you did not feel an out of balance driveshaft then you were completely oblivious to what the vibration is. LMTVs have lots of high apeed hub vibrations you can feel from the gearing but a out of balance shaft if totally felt. You can test that by putting a few sticky wheel weights on the driveshaft. Add enough and that truck will bounce off the ground as it goes down the road. I would not believe that a bad driveline would crack a block. The 3116 and 3126 motors cracked due to a bad casting from France. Generally on the drivers side, three or 4 oil pan bolt holes towards the front. Weld the crack and roll on. A bad driveline will snap or walk out every bellhousing bolt way before it takes a motor out. Along with the joint holes on the yokes. They would be so loose and worn from vibration than the expression hot dog down a hallway will come into play. If you want to check for excessive vibration that you can't feel or tell then an infared gun is your friend. It will tell you if you have a vibration or joint on its way down

Your previous posts say you used neapco joints and not spicer and bragged about those locking tabs. Like apparently you had never seen them before. The locking tabs come in the cheap spicer SVLs that are mad in china. But not a genuine 1610, 1710 or 1810 joint assembly. They do not come with them. Period. I can take you to the spicer warehouse and you can look thru every box till your tired and you wont find one in a heavy joint produced by them. Along with the trucks that run them everyday without a tab. I am dragging 78,000lbs down the highway and there isnt a one on this truck. . So the question is. Did you replace your neapco joints with spicer then?

You may be some type of engineer or just try to expand your knowledge by reading alot but that is alot different than real world useage and knowing what you are dealing with in a hands on basis. Alot of the threads you have started are just information gatherings cause you are or were timid about hands on. Similar to the op here. He has posted threads about common failures, rebuilding the 3116 due to excess blowboy when he doesn't even know the proper of allowable blowby. Not to mention not driving it till then "weak links are fixed" no wonder its got blowby if it hasnt been driven and just idled around.


Enjoy your trucks. Dont worry about the what ifs and what coulds that other people have had happen. Its paranoia really. If stuff breaks during operation. Fix it. Simple as that. Wear and tear maintenance is far less than lack of useage maintenance.
 
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Awesomeness

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If you did not feel an out of balance driveshaft then you were completely oblivious to what the vibration is. ... I would not believe that a bad driveline would crack a block.
There are vibrations that can be felt, as well as unusual people like yourself perhaps that have driven a zillion miles and can feel everything. I'm not as experienced as you, but no newbie to mechanics and vibrations either, and I COULD NOT TELL even when paying attention for it. Whether you believe it or not there is no other plausible explanation as to why the block cracked, and the military engineering reports came to the same finding. What I said in my previous post is that it is foolish to hope you'll feel it, because the results can be very expensive.

Your previous posts say you used neapco joints and not spicer and bragged about those locking tabs. Like apparently you had never seen them before. The locking tabs come in the cheap spicer SVLs that are mad in china. But not a genuine 1610, 1710 or 1810 joint assembly. They do not come with them. Period. I can take you to the spicer warehouse and you can look thru every box till your tired and you wont find one in a heavy joint produced by them. Along with the trucks that run them everyday without a tab. I am dragging 78,000lbs down the highway and there isnt a one on this truck. . So the question is. Did you replace your neapco joints with spicer then?
Correct, I had to replace two of them because I had some friends helping me when we were doing the axle gear change, and they dropped some of the roller bearings in the dirt. I don't care how many warehouses you're going to take me to, I'm telling you the two Spicer joints came with them in the box. You were insinuating that because none come with them in the box, they must not be good/important/something, so I'm rebutting that by saying many of them do come with them in the box and that's poor logic.

I really like tab washers (as well as lock wire, castle nuts with cotter pins, etc.) because they never fail, except when corrosion or physical damage have occurred. I use them in a lot of my designs. I had never had tab washers on u-joints before, and I was definitely excited to get them! Locking adhesive (e.g. Loctite) works nearly as well, with the exceptions of oily/poorly-cleaned fasteners and hot environments, and the annoyance/labor of using fasteners that have it applied (once it has dried). Locking adhesives aren't bad, and I specify their use quite often too, but the mechanical locking methods are just better.

You may be some type of engineer or just try to expand your knowledge by reading alot but that is alot different than real world useage and knowing what you are dealing with in a hands on basis. Alot of the threads you have started are just information gatherings cause you are or were timid about hands on. Similar to the op here. He has posted threads about common failures, rebuilding the 3116 due to excess blowboy when he doesn't even know the proper of allowable blowby. Not to mention not driving it till then "weak links are fixed" no wonder its got blowby if it hasnt been driven and just idled around.
Enjoy your trucks. Dont worry about the what ifs and what coulds that other people have had happen. Its paranoia really. If stuff breaks during operation. Fix it. Simple as that. Wear and tear maintenance is far less than lack of useage maintenance.
Not sure where you're going with this, but I think you're hearing what you want to hear. While this is the first and only military truck I've owned, I've never been timid about hands-on. Yes I am an engineer (for air, land, and sea vehicle mounted equipment), so we do a lot of work and testing to understand what is actually going to happen with things like vibration, locking adhesives (and other types of locking fasteners), pressure hoses, mechanisms, etc. Shade-tree mechanics and field-fixes are dangerous things, because they don't really "know" (e.g. don't know that Green and Blue Loctite are the same strength, is a great example). Sure, we engineers don't get everything right the first time, but we're at least trying to.
 
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Reworked LMTV

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You are WAY off base here. If people are timid, so what? All of us can operate a hammer frankly. If people want to help others learning these machines, so what? This place is a mess of information, and it is mostly disorganized. If I make a easy to digest pictorial to help others reduce the risk of a serious failure, so what? If I have questions about my engine's blowby, so what? Yes, you can calculate it, but most of us don't have the blowby analyzer anyway. Frankly, I was thinking out loud potential cost if it needs a rebuild. Does that bother you???? Funny, I just came in from driving my truck all of the place, but even if it sat until I fixed every last thing, you guessed it, WHO CARES?


Sleeve retainer is rated at 3000psi just as red loctite. It actually works better at filling in the gaps. It has
to be removed with heat as well.

If you did not feel an out of balance driveshaft then you were completely oblivious to what the vibration is. LMTVs have lots of high apeed hub vibrations you can feel from the gearing but a out of balance shaft if totally felt. You can test that by putting a few sticky wheel weights on the driveshaft. Add enough and that truck will bounce off the ground as it goes down the road. I would not believe that a bad driveline would crack a block. The 3116 and 3126 motors cracked due to a bad casting from France. Generally on the drivers side, three or 4 oil pan bolt holes towards the front. Weld the crack and roll on. A bad driveline will snap or walk out every bellhousing bolt way before it takes a motor out. Along with the joint holes on the yokes. They would be so loose and worn from vibration than the expression hot dog down a hallway will come into play. If you want to check for excessive vibration that you can't feel or tell then an infared gun is your friend. It will tell you if you have a vibration or joint on its way down

Your previous posts say you used neapco joints and not spicer and bragged about those locking tabs. Like apparently you had never seen them before. The locking tabs come in the cheap spicer SVLs that are mad in china. But not a genuine 1610, 1710 or 1810 joint assembly. They do not come with them. Period. I can take you to the spicer warehouse and you can look thru every box till your tired and you wont find one in a heavy joint produced by them. Along with the trucks that run them everyday without a tab. I am dragging 78,000lbs down the highway and there isnt a one on this truck. . So the question is. Did you replace your neapco joints with spicer then?

You may be some type of engineer or just try to expand your knowledge by reading alot but that is alot different than real world useage and knowing what you are dealing with in a hands on basis. Alot of the threads you have started are just information gatherings cause you are or were timid about hands on. Similar to the op here. He has posted threads about common failures, rebuilding the 3116 due to excess blowboy when he doesn't even know the proper of allowable blowby. Not to mention not driving it till then "weak links are fixed" no wonder its got blowby if it hasnt been driven and just idled around.


Enjoy your trucks. Dont worry about the what ifs and what coulds that other people have had happen. Its paranoia really. If stuff breaks during operation. Fix it. Simple as that. Wear and tear maintenance is far less than lack of useage maintenance.
 
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Csm Davis

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Okay so I love how some are saying that they have had a shaft rebuilt and did not have it balanced. If the shop that rebuilt your shaft didn't balance it after cutting it apart and welding it back together you need a new shop unless you got stupid and told them not to balance it. I have talked to Spicer engineers about light, medium, and heavy driveline and trueing and balancing any high speed shaft ie road driven vehicles is the only way to get rid of vibration and self destruction. You also don't want a dead straight shaft and u-joints. You need at least 3° to get the needles to move around in the cups. Also the bolt retaining straps are okay but are more expensive than locktite, I think both are inferior to wiring and have seen both fail. Out of anyone in this thread if I had to load up and drive 2000 miles in an unknown truck I would grap a bag of tools and Simpson. He has worked on and driven more military vehicles and miles than anyone who hasn't been deployed for the last four years straight. Not saying that you guys aren't good guys but he has the experience.

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