Correct Driveshaft Length for 700-R4/NP208/14bolt FF

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AuroraGirl

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not huge on the wheels but they are also way more refrained than the ones that hurt my eyes so ill allow it. nice truck lol
 

scrap--metal

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Its 54" inches without a lift and 55"with a 12 inch all suspension lift no blocks...
Mine is a 81 single cab longbed, 700r4, 208 tcase, 14 ff rearend , i just has my driveline built, havent gotten a chance to drive it yet (no brake lines) but it seems itll work perfectly....it sits about 2 inches out of the tcase for movement

Thanks for the measurements. The 54 3/8" N.O.S. M1008 drive shaft I bought off eBay fixed my driveshaft vibration problem, so I'm all set there. Still have plenty of other things to work out on the truck, but at least that one's off the list.
 

AuroraGirl

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So what's in your old truck for a driveshaft?
So I dont trust the tape measure that much because i measured with a small "throw in" tape that comes with those cheap tool kits, and the results seemed weird, so i was gonna remeasure with a reel tape measure that is older than you and i together so I trust the build quality. But prelim circumference was damn near 11 inches on the spot so if you divide by pi you get something damn near 3 3/4 inches but because i am not trusting that measure im going to say it could at most be 4 inches diameter but that does seem like it may be an overshoot. Length, I had something over 4 feet but not much longer and I was only measuring from the tube end to tube end, not the ears by the u joint, the thing wasnt even long enough so that measurement is only that specific for that reason. however, in a not-good way but in a "neato" way this is how much of the slip yoke was sticking out where I last had the truck parked:
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and yes, the "yikes" of that situation does not escape me.

Also, not related, but these MFers decided they were gonna start coming undone/loosening.
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how rude
 

scrap--metal

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To me, yours looks like the smaller K20 driveshaft I took out of my truck.

Are the sleeves really coming loose? That doesn't seem right... Usually the ends are what gets sloppy.
 

Grit dog

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Are the sleeves really coming loose? That doesn't seem right... Usually the ends are what gets sloppy.
Especially considering the copious amounts of brown loctite (rust) that is present.
I had one of those adjuster sleeves frozen up on a 10 year old rust free truck, recently. Agree, unusual thing to randomly come loose, ever.
 

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To me, yours looks like the smaller K20 driveshaft I took out of my truck.

Are the sleeves really coming loose? That doesn't seem right... Usually the ends are what gets sloppy.

Especially considering the copious amounts of brown loctite (rust) that is present.
I had one of those adjuster sleeves frozen up on a 10 year old rust free truck, recently. Agree, unusual thing to randomly come loose, ever.

Several years ago, I had my drag link sleeve skip a thread after an offroading event. I heard a mild pop in the front and then my steering wheel was no longer centered. The sleeve bolts still seemed tight, but they had evidently loosened up enough to let it move. I readjusted the drag link and really cranked on the sleeve bolts, it's been fine ever since.
 

AuroraGirl

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Several years ago, I had my drag link sleeve skip a thread after an offroading event. I heard a mild pop in the front and then my steering wheel was no longer centered. The sleeve bolts still seemed tight, but they had evidently loosened up enough to let it move. I readjusted the drag link and really cranked on the sleeve bolts, it's been fine ever since.
The one appears to be loose and the other appears to be tight still. this was a truck abused in its last years for plowing dirt and my learning curve of an experience. including the slipping off the driveway when a axle shaft broke going up, the driver side would less likely have been affected in that specifically... so strange, but my grandpa put new suspension on it prob in the mid 90s and the truck didnt see much miles before it finally was parked because he got the f150.

Beings it was my gpa, he very possibly didnt tighten it and its showing now, this was it last summer when I started really learning and getting into it prob early summer. So its been at least not as tight as it should be it seems?
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im guessing the old PS pump which was very choppy even with RPM was a good way to shock the part with assist dropping in and out(theory, that could be wrong but made sense to me) and the larger width tires which were on the front also bearing the weight of the way too heavy and large plow my gpa had put together. Makes sense to me at least, all that extra weight, periodic getting stuck, choppy ps, lots of rough ground on a part of the yard. Plus an oopsie years ago to get it tight enough. I think the front shocks are probably toast or pretty much the equivalent, I could see that maybe factoring.

I have never replaced or adjusted these before, do you unclamp (loosen) and jack up front end, slide in to where you want it, and then clamp by tightening? The toe is visibly out of wack now thats how much it wiggled out. good thing I noticed.
To me, yours looks like the smaller K20 driveshaft I took out of my truck.

Are the sleeves really coming loose? That doesn't seem right... Usually the ends are what gets sloppy.
I think the passenger side may be ok, but the driver for sure
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this was an older pic, it looks like the amount of threads exposed has not changed much if at all on pass side.
 

Grit dog

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The way that works is both rods are threads and so is the sleeve. Loosen the clamp bolts and turn the sleeve to adjust the overall length. Good news is it it did this, the sleeve is not frozen to the tie rods.
If it just skipped threads and didn’t strip either, you will be able to adjust easily. I’d consider taking the weight off that wheel at least for large adjustments. Less chance of stripping more if threads stripped at all.

Know there’s a bit more to aligning it and keeping full steering both directions steering wheel lined up etc, however eyeball straight for a yard truck is probably fine.
 

AuroraGirl

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The way that works is both rods are threads and so is the sleeve. Loosen the clamp bolts and turn the sleeve to adjust the overall length. Good news is it it did this, the sleeve is not frozen to the tie rods.
If it just skipped threads and didn’t strip either, you will be able to adjust easily. I’d consider taking the weight off that wheel at least for large adjustments. Less chance of stripping more if threads stripped at all.

Know there’s a bit more to aligning it and keeping full steering both directions steering wheel lined up etc, however eyeball straight for a yard truck is probably fine.
thank you good sir. i think i will probably Get it back to close before I park it for the year. At the moment, I have a different height tire on the front. I might throw my tires i just pulled off the trailer on the front so the tires match at least on height.(still no 4x4 because the height will be taller than rear)
I suppose a short radial and a tall bias on the front is not helping this lol
 

ak4life

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not huge on the wheels but they are also way more refrained than the ones that hurt my eyes so ill allow it. nice truck lol
Thanks aurora girl, i can only think of two things when seeing your profile name,, the aurora borealis (from my home state Alaska) or colorado, i think we will get along just fine.....haaahaaa! Thanks for the slide on wheels...lol
 

ak4life

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the weather checking is definitely more pronounced this last year than when I put them on. If they werent sitting in a small tripod pile in my moms yard since they were replaced by my step dad on his old 2005 chevy truck a few years back, directly in the sun and weather, face up, fileld with water etc etc, Im sure they wouldnt be as bad. But considering they sat in the sun and froze a few times, etc, I commend them for still holding it together and thats after my winter using the plow and the truck definitely putting the weight on those front ones while the rear ones just did their normal duty. 2k on the rear + the trucks normal weight, with the nose of the truck favoring the front ones probably isnt that hard on a 10 ply tire pair on the rear lol. at low speed.

on the driveshaft thing, diameter, circumference, those both would work. Im just wanting to know the "large" ness of the driveshafts compared to mine. I can measure mine. If you have the diameter you can find the circumference with a simple equation and if you have the circumference.. well frankly you only really need one or the other. if you do that for at least the one you put on your truck(from CUCV) that would be appreciated. But if you also do your one you removed, I would appreciate that too.

I just dont know what mine came off of technically, and the shear amount of trucks that were snipped up and parted and came through etc I dont know what it would be. I learned the np208 and cross member I have were probably, but this probably was not certain, out of two different vehicles, because my uncle says he was pretty sure the truck the np208 and sm465 came out of wasnt the same wheel base but he could remember if it was a short bed truck, possibly out of a GMC jimmy(which they had for a few years apparently) or if it all came in like a trade.. basically I could have a driveshaft that was *close enough* and if that is the case, I may just seek a CUCV one like you :)
Oh to add to info on my driveshaft if any of it is helpful to you, and hope it is
 

ak4life

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81/84 gmc, 2001gmc, 2003 gmc, 2005 chevy
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longbed squarebody, longbed 4dr extended cab, yukon sle, 4dr ext. cab
Engine Size
383, 6.0, 5.3, 5.3
Sorry, got cut short, i just was gonna add it basically an exact copy of a 1 ton driveshaft with correct length for my setup.....ok that is all. Good luck with search..
Oh to add to info on my driveshaft if any of it is helpful to you, and hope it is
 

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