1/2 ton cv swap kit

[atvspeed4]

We were working on a front diff swap on my hummer H3 today and while we had things apart we took a few measurements and realized we can build a kit to use 1/2 ton chevrolet CVs in a stock hummer h3. They are alot cheaper and easier to find and when we compared them side by side they are also an increase in size. We are about 75% there. Once everything is done I will post up pictures if anyone is interested or has any comments.

 

[06 H3]

:hans: Im excited! Cant wait to see how it goes.

 

[cgalpha08]

Sounds interesting, im assuming these are stronger than the stock H3 ones?

Sent from my DROID BIONIC using Tapatalk

 

[06 H3]

wait...isnt the H3 a 1/2 ton already?

 

[atvspeed4]

wait...isnt the H3 a 1/2 ton already?

I'll get a picture of the two CVs next to each other when we do the final install. They are the flange style and are definitely larger.

 

[Mr_Rich]

I think the half-shafts in my '89 Chev K1500 are the same as the ones in the H2's. They would definitely have to be modified to work in an H3/ H3T. I'll look forward to the final install as well...

 

[3Hummers]

Interesting.

 

[JoshuaL]

:corn:

 

[ReconH3]

Just something to bear in mind. On a trail, it's easier to replace a CV than a diff.


"Ex Umbris Venimus"

Sent from my iPhone

 

[atvspeed4]

Just something to bear in mind. On a trail, it's easier to replace a CV than a diff.


"Ex Umbris Venimus"

Sent from my iPhone

Very true but it is easier to find a 1/2 ton shaft at your nearest parts store than a hummer h3 shaft...

 

[4speedfunk]

The problem isn't the half-shafts. Its the stuff in between em that breaks.

 

[05Mudiak]

Very interested :corn:

how much different in size are the actual cv joints?

 

[bebe]

The one tons fit too.

We opted against the Chevy 1/2 ton as they have less travel capability than the OEM H3 shafts. The 3/4-1 tons have similar travel, a teeny bit more than the H3.

The half ton shaft and the 1 ton both have tri-pot/pod inners. If you don't set the plunge absolutely perfect, when you are at full droop or full compression, as the axle slides back in it breaks the cup.

The H3 shaft is a rezeppa on both ends. Which for longer travel is actually the best option. RCV makes an HD H3 shaft.

Looking for a cheaper alternative? May as well go to the 1 ton. They are the same price as the 1/2 ton.

 

[atvspeed4]

The one tons fit too.

We opted against the Chevy 1/2 ton as they have less travel capability than the OEM H3 shafts. The 3/4-1 tons have similar travel, a teeny bit more than the H3.

The half ton shaft and the 1 ton both have tri-pot/pod inners. If you don't set the plunge absolutely perfect, when you are at full droop or full compression, as the axle slides back in it breaks the cup.

The H3 shaft is a rezeppa on both ends. Which for longer travel is actually the best option. RCV makes an HD H3 shaft.

Looking for a cheaper alternative? May as well go to the 1 ton. They are the same price as the 1/2 ton.

That was our original plan, after many hours surfing the various full size chevy forums and taking measurements ourselves and then actually mounting one up and running through its travel we discovered a few things. The half ton cv is actually about 7/8" shorter than the one ton cv. This allows us to machine a stub flange that fits into the stock differential and still be able to bolt up the cv. From full bump to full droop the half ton CV had enough travel for the stock suspension even with the shock removed to have a little more droop. We could/ would prefer to run the one ton cv but would have to machine a custom intermediate shaft to shorten the CV at least 7/8" which defeats the purpose of having a cheaper alternative and easier to source. The tough part right now is build a stub flange that fits tight enough to the differential to allow the CV to compress enough to not break the cup.

Any ideas?

 

[Happy Hummer]

Waiting to hear and see more on this topic.
Chris

 

[bebe]

How are you measuring? Are you fitting the CV in the truck at ride height? You will not get an accurate measurement on a bench.

The rezeppa style joints have much less plunge than the tri-pots.

The reason the H3 shaft is more expensive is because of the double rezeppa, it's a much better shaft, stronger (because it's male) and has more reliable travel.

What is the current price difference between the three shafts?

O'Relly carries H3 CV's (Master Craft) for $85.99 - 24" 7/8"

They have a Chevy 1500 CV (Master Craft) for $59.99 - 21"1/16"

They have Chevy 3500 CV (Master Craft) for $59.99 - 21" 11/16"

There is 5/8's difference between the 1/2 ton and the 1 ton, which can easily be compensated for in your stub axles.

Are you making micro stubs as long as the male portion of the inner? Are you using the snap ring or a Dutchman style retainer?

Are you going to pray every time you wheel for no side load?:wink::gaah:

Honestly, I can't visualize where you are going with this, but I'm open.

I don't know what the common breakage point is on the half shaft. I've been pretty lucky I guess, I have never broken one (knock on wood) but I have gone through my share of ring gears and front diffs.

 

[bebe]

Can you make a single shaft on the long side to eliminate the intermediate shaft all together? That would be cool, and stronger.

Who is making these stubs? Do I know them?

 

[atvspeed4]

How are you measuring? Are you fitting the CV in the truck at ride height? You will not get an accurate measurement on a bench.

The rezeppa style joints have much less plunge than the tri-pots.

The reason the H3 shaft is more expensive is because of the double rezeppa, it's a much better shaft, stronger (because it's male) and has more reliable travel.

What is the current price difference between the three shafts?

O'Relly carries H3 CV's (Master Craft) for $85.99 - 24" 7/8"

They have a Chevy 1500 CV (Master Craft) for $59.99 - 21"1/16"

They have Chevy 3500 CV (Master Craft) for $59.99 - 21" 11/16"

There is 5/8's difference between the 1/2 ton and the 1 ton, which can easily be compensated for in your stub axles.

Are you making micro stubs as long as the male portion of the inner? Are you using the snap ring or a Dutchman style retainer?

Are you going to pray every time you wheel for no side load?:wink::gaah:

Honestly, I can't visualize where you are going with this, but I'm open.

I don't know what the common breakage point is on the half shaft. I've been pretty lucky I guess, I have never broken one (knock on wood) but I have gone through my share of ring gears and front diffs.

Micro stubs with the snap ring retainer. I guess I am one of the unfortunate few that has exploded a outer driverside cv and also the female end of the intermediate shaft which took out the cast aluminum housing around the female end that the CV goes into. We were working on another project to make one piece long side shafts for the silverado 1500/ 2500 trucks as we were having issues with the weak slide collar on the front axle shaft breaking. This gave us the idea to start doing a little investigating on my h3. Cost wise, as long as their is enough clearance through where the intermediate shaft connects to the female coupling that the CV goes into, it should be the same to have a one piece shaft made for the long side. That was our original plan but making the flanged stubs short enough while being long enough to clear the heads of the differential mounting bolts has become a problem. For sizing up the shaft we had it in the truck with a mock up flange at full droop, ride height and very close to full bumpstop compression. The shop, its in Massachusetts near us Mitchell Differentials.

Also its not as much of cost as it is availability. To get a CV near me has become a special order only task unless we go to the dealer. I am familiar with the different styles of "CVs" and I just do not see the 1/2 ton shaft being weaker than the H3 shaft. I've wheeled with 1500 silverados that have much larger tire size and power output than us and I am the one that ended up breaking the CV. Yes, there are soooo many factors that go into breaking a CV I know but for a off the shelf alternative to our CVs the 1500 has a larger outer CV and thats the one that I exploded.

 

[bebe]

Micro stubs with the snap ring retainer. I guess I am one of the unfortunate few that has exploded a outer driverside cv and also the female end of the intermediate shaft which took out the cast aluminum housing around the female end that the CV goes into. We were working on another project to make one piece long side shafts for the silverado 1500/ 2500 trucks as we were having issues with the weak slide collar on the front axle shaft breaking. This gave us the idea to start doing a little investigating on my h3. Cost wise, as long as their is enough clearance through where the intermediate shaft connects to the female coupling that the CV goes into, it should be the same to have a one piece shaft made for the long side. That was our original plan but making the flanged stubs short enough while being long enough to clear the heads of the differential mounting bolts has become a problem. For sizing up the shaft we had it in the truck with a mock up flange at full droop, ride height and very close to full bumpstop compression. The shop, its in Massachusetts near us Mitchell Differentials.

Also its not as much of cost as it is availability. To get a CV near me has become a special order only task unless we go to the dealer. I am familiar with the different styles of "CVs" and I just do not see the 1/2 ton shaft being weaker than the H3 shaft. I've wheeled with 1500 silverados that have much larger tire size and power output than us and I am the one that ended up breaking the CV. Yes, there are soooo many factors that go into breaking a CV I know but for a off the shelf alternative to our CVs the 1500 has a larger outer CV and thats the one that I exploded.

Gotcha...

So obviously the OD of the 1 ton flange is much larger, and of course in my build we didn't come across that because we gutted it an started from scratch.

Massachusetts style wheeling is quite a bit different than Sierra Style, I can see why that necessity is the mother of your invention. You need something that will hold up to more high speed stuff like muddy trails w/ rocks etc.

H3's are very heavy front end vehicles. Spinning a tire and then getting sudden traction will do exactly as you described, shock load destruction...sucks, but it's fun to watch . Since you have the CI diff, the next weakest point is going to be the Intermediate and the CV, but IMHO, that's a hell of a lot better than getting strapped off of Golden Spike for 7 hours.

At least if you break a CV you can replace it, (always carry a spare), repairing an intermediate is a little more surgery, but not like blowing an R&P.

I didn't say the 1/2 ton was weaker than the H3, I said it had less travel. The outer may be larger and stronger than the H3 (I think they are the same 33 spline rezeppa) but honestly The inner won't have as much travel and that's where you will run into issues. The H3 has much longer travel than a 1500.

Get the front end corner weights on the H3 vs 1500 and maybe that will explain the difference?

As for the I/S, I haven't torn one apart in a while, but you should be able to make that happen. In fact, I think that may be the true savior in this protect.

Here is a link to the build we did, not sure if you have seen it, but everything relevant to this conversation is in the first 70 or so posts

http://www.pirate4x4.com/forum/showthread.php?t=915987

 

[silvrzuki77]

Props for all the investigating you have been doing latley. Put me at the top of the list for your tierods!

 

[atvspeed4]

Thanks Bebe, I've followed your build since you first posted up. I was hoping you would chime in and add some of your findings to this thread. Also oddly enough I do not have the cast iron front diff, just aluminum in my past three hummers and never had an issue with the ring and pinion or cracking the actual case (crossing my fingers) We were looking into swapping a High pinion dana 30 when we started measuring up for this project but it just doesnt look like a high pinion would even come close to fitting in this application with all of the measuring we did. The one ton CV was too long for the stock suspension when we measured it. The cv would not only compress and crack the cage but it also would hit the mount for the diff off the frame. I really would like to make the long side shaft one piece like we were talking about above.

As for the tierods I am just waiting for the tie rod end company to build a prototype. They said they needed some time but would pick up a stock inner soon to take the necessary measurements.

 

[bebe]

Well then it sounds like I'm not much help...I guess proceeding with the 1/2 ton will work. The single long side shaft will be a good direction.

The only other diff I would try to "stuff" in there is the AAM925. Have you tried that yet?

 

[06 H3]

We were looking into swapping a High pinion dana 30 when we started measuring up for this project but it just doesnt look like a high pinion would even come close to fitting in this application with all of the measuring we did.

There is very little room by the diff as you already know but my question to people who have done or thinking about diff swaps is why go high pinion? I understand high pinion is better for a solid axle design as it gives more clearance behind the diff but for us wouldnt a low pinion be better seeing its is more accommodating to the little clearance we have? I have the rancho lift now and there is a decent amount of room there now I think for a rancho guy looking to do this it would be a bit easier.

 

[atvspeed4]

There is very little room by the diff as you already know but my question to people who have done or thinking about diff swaps is why go high pinion? I understand high pinion is better for a solid axle design as it gives more clearance behind the diff but for us wouldnt a low pinion be better seeing its is more accommodating to the little clearance we have? I have the rancho lift now and there is a decent amount of room there now I think for a rancho guy looking to do this it would be a bit easier.

Its more than ground clearance, with a high pinion in a front application you are running on the "drive" side of the ring gear teeth instead of the coast side like you would in a low pinion application. I will try to find the article, but I was reading that as far as ring gear strength the smaller dana 30 HP is actually stronger than the larger dana 44 low pinion due to running on the proper drive side of the teeth. Before everyone jumps on this, the 30 does have smaller tubes and is prone to bending tubes in a solid axle application but after trying to fit one, it doesn't even come close.

 

[atvspeed4]

I was reading on one of the other hummer forums that a while ago 4digr put a dana 44 in his stock height but required custom CVs, crossmember and to cut the skidplate. Does anyone know if that was a high pinion or low pinion?