Thinking about upgrading my HMMWV half-shafts

[steelsoldiers]

Hi guys,

I've been hearing one of my front halfshafts popping lately. I suspect it is the front-left but it is a little tough to localize with all of the engine noise. My first instinct is to buy both front A0 10k shafts and swap them out, but the gearhead in my says why not upgrade while I'm at it. It's only a matter of time before the obscene torque from the Cummins exceeds one of the stock shaft's limits. So, my options are as follows:

1. Replace stock shafts with like
2. Replace stock shafts with upgraded A2 shafts
3. Replace stock shafts with 12k shafts and swap out hub gears for 12k units
4. Replace stock shafts/hubs with 12k units

I love the idea of 12k shafts/hubs because of their toughness. I may need them since I will be adding power to the Cummins at some point this year and the final torque numbers will be over 600 lb-ft. The downside is it is a $$ and time consuming upgrade.

Then again, maybe the upgraded A2 shafts will be adequate for a while. What should I expect to spend on those? There are listings on evilbay for $325-365/shaft. That sounds high to me, but is that about average? I check HPG.com and he was around $450.

I know some of you guys have done half-shaft/hub upgrades over the years and I would like to hear about your experiences.

Chris

 

[patracy]

My non-experienced with HMMWV .02

Max it out.

If you start playing with the cummins, you're going to be sending WAY more power than a 6.2 could ever dream about. My "medium" dodge lays a tad over 1000ft-lbs to the rear wheels. Now granted the shafts won't see all of that due to the gear reduction units, that's still A LOT of power to it.

The 6.2 was only 330ft-lbs. You'll easily double that with your setup.

Course my right foot can be very heavy at times.

 

[gimpyrobb]

I agree, bite the bullit now, or spend the money twice later.

 

[patracy]

Or in my experience spend the money twice with a little extra for the other stuff you broke.

 

[TedG]

Upgrade sooner than later. Install all new/used 12k hubs and half shafts. You will also need to modify the brake caliper brackets so they do not rub, or replace brackets. Also consider 3.08 diffs.

I know where you can get these things...lol

 

[jwaller]

I swapped all mine over while I was on the 6.2 and now that I'm with the 6.5 Turbo I'm glad I did. the diff in size is substantial and well worth the weekend it took me to do the job.

I also went with H1 alpha hubs while I was at it. IMO It's the best and only option for gear hubs.

If you want you could do the front diff centering mod so you only have to buy 2 different shafts for the whole truck. good idea for you since your not staying with the mil-spec driveline.

 

[steelsoldiers]

I also went with H1 alpha hubs while I was at it. IMO It's the best and only option for gear hubs.

If you want you could do the front diff centering mod so you only have to buy 2 different shafts for the whole truck. good idea for you since your not staying with the mil-spec driveline.

Good to know. What benefits do the Alpha hubs have besides the helical gears and the CTIS provisions? I'd like to center my front diff, but it won't work because of interference between the Cummins and the drive-shaft and diff.

Upgrade sooner than later. Install all new/used 12k hubs and half shafts. You will also need to modify the brake caliper brackets so they do not rub, or replace brackets. Also consider 3.08 diffs.

I know where you can get these things...lol

Please shoot me a PM or email sometime on where to get a good deal on REV diffs, shafts and hubs.

Course my right foot can be very heavy at times.

Mine too. That's why I figured an upgrade would be in order. Especially once I go to 39-40" tires

I agree, bite the bullit now, or spend the money twice later.

Agreed. I hate fixing things twice.

 

[WOLFER]

We 10k halfshafts that are military grade with the latest improvements. Outlast old style 10k shaft by double.

 

[1993]

What are the part numbers for the old and the new improved 10k shafts(10.3k)?
Is part number 12341985-4 (2520-01-382-872)for the upgraded front right shaft?
Planning on replacing only one shaft(due to blown dust boot) for now.
12k's would probably be overkill since I have a stock 6.2 and I am light on the throttle.

But I have twisted a shaft on a custom dune buggy once upon a time. looked like it was made of toffee. heavy foot was a major factor...

 

[Retiredwarhorses]

You can upgrade a 10k hub to 12k by changing out the upper spur gear with a 12k...the gears are on sleeze bay.
ctis option only adds a bunch of uneeded parts...

 

[1993]

as I just mentioned, I would like to avoid installing the 12k shaft since I'm only replacing one shaft.
However, I figure I might as well upgrade the original 10k to a 10.3k since it's heavier duty and doesn't require modified hubs/gears like the 12k.

My question was just about double checking the part numbers.

 

[Retiredwarhorses]

as I just mentioned, I would like to avoid installing the 12k shaft since I'm only replacing one shaft.
However, I figure I might as well upgrade the original 10k to a 10.3k since it's heavier duty and doesn't require modified hubs/gears like the 12k.

My question was just about double checking the part numbers.

my reply was not to you....it was the OP....the thread you hijacked.

 

[1993]

Thought I was just bringing it back to life from a nap it started in 2012.
Figured why start a new thread(and create clutter) when this one already related so closely to my one question.

Your info on 12k shafts is appreciated but it might be a little confusing if reading the posts in chronological order

 

[Retiredwarhorses]

My bad....I didn't even look at the OP date...my apologies

 

[1993]

No worries


Still wondering if I've got the correct part numbers...
Thankfully I'm not in a hurry, It's just an open dust boot for now, probably won't replace it until the joint starts clicking...

 

[TedG]

Replacing a boot is very simple so why wait?

 

[1993]

For the price of two boots I can have a whole new upgraded shaft with two new boots included.
And without the labor of cleaning out the contaminated grease and repacking the boot. Also,who knows how long that boot has been open...

 

[TedG]

My point is why wait until it you hear clicking which might be during a catastrophic failure (broken brake line, etc.). Boots can be found for the 7.7 half shafts for very little money and it does not take long. Or at least pack it with grease and wrap with stretch wrap.
Labor on a hobbie is just good learning and really doesn't cost anything.

 

[bigred350]

Hi there I have an 1987 m998 how do you know if you have the 10k or the 10.3k half shafts other than maybe finding part numbers. My shafts are all in good shape but my hub seals are leaking where the shaft goes in so i have to pull them to replace and was just wondering? Also does anybody have a part number for the seal? thank you

 

[actionpaintball]

I also recommend centering the front differential and being able to carry a single replacement shaft. All four corners of my Humvee use a standard 12k shaft.