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Swapping a 10 bolt rear for a 14 bolt semi floater

Jorge6.5

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Upstate New York
I recently bought a k1500 5 speed on the cheap. The 10 bolt rear is toast after driving it for a week.

I called the local salvage yard for a replacement. They had a 10 bolt and 14 bolt. The 10 bolt was shot, they said the 14 bolt semi floater will work fine and it is the same price. So I took it.

Now I'm questioning if the yoke will work with the u joint on the drive shaft? If not, are the yokes interchangeable?

Are there any other issues to watch out for? Right now these are the only questions I have. If I have more, I will report back.

Thanks guys!
 
That's what I was afraid of. So many people on the net with different opinions about the u joints. Can't get a straight answer, different ones for aluminum and steel drive shafts.

For now going through swap and playing it by ear with the yokes and u joints.
 
The 14 bolt uses a 1350 u-joint for external snap rings(unless you have one of the rare 14 bolts out of a 1500 in which case it COULD have a 1330 or S44, but could also be a 1350), and most likely your stock driveshaft has the S44 internal snap ring u-joint. If so I just helped a friend with one of these and ADVANCE and NAPA both carry the bastard joint to do this swap with no modifications. One thing of note is to make sure and get axle from a 4X4, his came from a 2X4 2500 and it is 4 inches narrower than his old axle(10 bolt 1500) and his tires hit the springs because of it. If your 1500 uses the S44 joint, then a NEAPCO 2-1153 or PRECISION 447 u-joint will allow the driveshaft to bolt right up with no modifications. If you let us know exactly what truck you have and wether the driveshaft is 1 or 2 piece, and aluminum or steel, and standard or extended cab and I can try and see which u-joint you currently have and see if they make a bastard joint to work.
 
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That's what I was afraid of. So many people on the net with different opinions about the u joints. Can't get a straight answer, different ones for aluminum and steel drive shafts.

For now going through swap and playing it by ear with the yokes and u joints.
I did a quick check, and it looks like if you have an aluminum driveshaft you have either a 1330, or a 1330 to S44 bastard from the factory. If you have a steel shaft it should be an S44. If it is a 4 speed it could also be a 1310 u-joint. There is ALOT of different options with GM as to which u-joint you have with a manual trans, but most all of the autos got the S44 internal snap ring style. Also you will need a torch to remove the u-joint as it is glued in with a nylon rope as well as held in with internal snap rings. If you have a micrometer you can take some basic measurements and wether it is an internal or external snap ring and look them up.
 
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The truck is a 1990 Chevy K1500 5 speed standard with short bed and standard cab. Truck has a steel driveshaft.

I'm not 100% sure on the donor truck of the 14 bolt semi floater. All I know is it came from a gm 4x4 truck 6 lug. I'm pretty sure the donor rear end had an aluminum driveshaft.

AFAIK the rear ends are the same width.

Thanks for the help
 
From the parts catalog if it has a 1 piece steel shaft and a regular cab, it should be an S44 u-joint. And the numbers I listed above will work provided the rear axle has a 1350 joint(if it came from a 2500 it should be a 1350 as that was standard across the board with GM for all 2500/3500 trucks for the most part until 01). This page has a pretty good breakdown of u-joint sizes so you can make sure which you have and which you need. http://coloradok5.com/forums/showthread.php?t=162259 If your current u-joints use an internal lock clip(half moon clip on the inside portion between the u-joint and the driveshaft), then it is pretty safe to say it is an S44 or 3R joint. And there is about a 98% chance your 14 bolt is a 1350, so the bastard joint you need is pretty common and easy to find for under $25 from NAPA. Only downside to it is that you have to remove the driveshaft to grease it because of where they put the zerk fitting at. And being it is from a 4X4 it should be the same width(or pretty close), I know the one I just helped with came from a 2 wheel drive and he now needs to get wheel spacers to run the stock wheels with his 285 tires.
 
Thanks a lot for that info and link! I'm sure it will come in handy.

I just got to where the truck is and measured the width of the yoke on the diffs, I got the same measurements. 3 and 7/8" luckily the salvage yard left one of the u joint caps in the yoke of the 14 bolt. I popped it out and put it against the caps of the u joint on the truck and by the looks of it, the caps look to be the same size and matched right up.

Tomorrow will be the day I find out for sure once I go through the swap. I will keep you guys posted on my results.

Will I be able to reuse the parking brake cables from the 10 bolt on the 14 bolt? I would like to retain the parking brake on my truck, after all it is a standard transmission.

Thanks again!
 
I don't think the parking brake will work as the 10 bolt uses a completely different style brake shoe arrangement, but it doesn't hurt to try.
 
Guess I'll find out tomorrow. If it doesn't work, will I just need parking brake cables for a 14 bolt truck?

The parking brake doesn't work now but won't be the end of the world if I don't get it working by tomorrow. Sure would be nice if it does work out with what I got. At least I'll have my regular brakes in order. I'm thinking about making my own setup to bleed the brakes on my own via a home made setup from what I found on the net.
 
You should be able to either get cables for a 2500 light duty truck or a later model 1500 with the 9.5" as most 6.5 1500's got the 9.5" rear axle.
 
Thefermanator- are the yokes interchangeable between the 14 bolt sf and the 10 bolt?

By the looks of it the u joint won't match up after all. Trying not to spend more money then I already have.

Thanks so much for your help so far
 
Ok, I got the rear end painted and bolted into the truck. All that is left is to get the drive shaft hooked up. I called the local Napa and they say they have the right conversion u joint in stock. I'll pick that up tomorrow and hopefully have that and the breaks hooked up.

Turns out, this 14 bolt sf is wider then the stock 10 bolt. I can't remember exactly how much now but I think it's a 3" difference. By the looks of it , the front and rear are about the same width now.

Another thing I noticed is the leaf spring perches on the 14 bolt rear are slightly shorter then the 10 bolt leaf perches. Not a big deal cause the back end was much higher before and the height difference is not really noticeable. Maybe has something to do with the increased axle tube diameter on the 14 bolt.
 
Nope, the yokes don't interchange. The conversion ujoint won't break the bank, and makes it an easy swap. Heck GM even used a factory bastard joint on some 5 speed trucks.
 
Yes it was pretty straight foward swap especially once I figured out the proper u joint. It was the 447 presicion u joint.

Not only is the axle beefier, the brakes are much beefier too.

It is definitely a worth while swap and I recommend it to anyone who still has the stock 10 bolt rear.
 
The 14 bolt uses a 1350 u-joint for external snap rings(unless you have one of the rare 14 bolts out of a 1500 in which case it COULD have a 1330 or S44, but could also be a 1350), and most likely your stock driveshaft has the S44 internal snap ring u-joint. If so I just helped a friend with one of these and ADVANCE and NAPA both carry the bastard joint to do this swap with no modifications. One thing of note is to make sure and get axle from a 4X4, his came from a 2X4 2500 and it is 4 inches narrower than his old axle(10 bolt 1500) and his tires hit the springs because of it. If your 1500 uses the S44 joint, then a NEAPCO 2-1153 or PRECISION 447 u-joint will allow the driveshaft to bolt right up with no modifications. If you let us know exactly what truck you have and wether the driveshaft is 1 or 2 piece, and aluminum or steel, and standard or extended cab and I can try and see which u-joint you currently have and see if they make a bastard joint to work.
I'm in need of some guidance on this same subject. I am going to start my 14b swap I just want to get the correct rear end to start. My truck is a 98 k1500 the 10b rear end in it now is about 67" wide. I've found two 14b tears that have both been 65.5" wide. Is this what I have to use or is there a 67" wide 14b rear? If so what vehicles had those so I can order one?
 
I know the 9.5" 14 bolt semi floater was a factory option under k1500 trucks if it was ordered with the camper package. I don't know how wide they are, but they should be the widest.
 
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