10bolt front diff tech

[06 H3]

I could also go to camburg. I've got a few ideas ill post up when I get on a computer

 

[4speedfunk]

MkMcgreg came over to my place today...he had a mysterious "clunk" that we were trying to track down. It ended up being an upper ball joint that was completely smoked. What a stupid idea to make them the way they do. For the helluvit...we drilled and tapped it, and installed a grease fitting. Obviously its too late but, I wanted to let everyone know that you can install zirk fittings and squeeze some grease in there...it does work.

He'll have to replace the entire A-arm...simply because GM didn't provide zirks. 77,000 miles FWIW.

 

[atvspeed4]

We are not giving up on the 10 bolt diff as I said from the start we already took the measurements on this and knew that we would simply need to get flanged shafts cut like bebe did. And... you need to run 1500 shafts because they are shorter than the 2500 shafts. This should not add a major cost.

As for the upper control arms, we started that build as well but decided not to go forward with it as scorpworks said they were almost done with the design. They have not given us any update so should we start working on a design? Dont want to step on anyones toes...

 

[4speedfunk]

Adding flanges and running 1500 shafts is without question the way to go. The toughest part about the housing is adding the outboard bearings and seals...and that task gets much easier when you don't have to run "plug-in" type half-shafts. Having been nut-deep into chopping up an early 8.5" 10-bolt...I highly recommend choosing something else for a starting point. Either the Dana44 or the 8.6" 10-bolt (rear H3 diff), would be a better choice. Since you'de be making your own axle shafts, matching the splines is no longer an issue...just make em for whatever splines are in your diff. If you chose a D44, you could even upgrade to a 35-spline carrier and get your shafts made from chro-mo. It would hold up to almost anything you could throw at it. Follow it up with RCV 1500 shafts, and it would be the ultimate upgrade! I honestly can't think of anything else you could do to improve it.

Good to hear about the control arms. I don't think it would be too tough to build some. You'de just have to make a weld-fixture based on the stock ones...RH & LH, then weld em up. I personally don't have the experience in front-end geometry to start changing the pivot points but, I'm sure there are things you could do to improve the travel. For heaven's sake...spend the extra $.18 cents for grease fittings. GM couldn't seem to justify that!

 

[atvspeed4]

Id love to run a LP 44 but you need to run a bearing retainer like bebe did because there never was a dana 44 with c clips (the aluminum dana 44a had c clips but no selectable locker options). After measuring the space we are working with we found that there would not be room to run the bearing retainer. I attached a picture of the HP dana 30 we are working on for chevrolet S10 zr2 trucks and blazers. If you look at the short side you can see how short we can go without a bearing retainer. (We think we can take off another 0.75" from what is in this picture if the machine that cuts our splines will get close enough.



Could you get us a measurement of length from the crosspin to the edge of the cover mounting surface please? I am curious how much longer the shaft would be than our dana 30. We already have the bearings and seal that work perfect for this application and are really narrow but can withstand the load.

 

[atvspeed4]

I dont think it would matter if we started with a 8.6 vs an 8.5 because we will be running custom bearings and cutting our own shafts so we can just run a 30 spline locker carrier and cut the shafts accordingly.

 

[06 H3]

How much shorter are the 1500 shafts?? Will that affect travel?

The shorter the shaft, assuming the cv's have the same amount of movement the quicker it will bind

 

[atvspeed4]

You will be fine even if you squeeze a few more inches of travel. It's approx. 0.75" depending on the year

 

[4speedfunk]

there never was a dana 44 with c clips

More excuse to run a 8.6 from the rear of an H3.

I dont think it would matter if we started with a 8.6 vs an 8.5

Oh it matters. The 8.6 comes with an Eaton locker, matching 4.56 gears, and 30 years of improvements. You can cut the ends of the tubes off and re-weld them within inches of the pumpkin, you can use modern late model seals and bearings...easily available, it already has C-clips, and the spline count/shaft size is a vast improvement over anything else in its size range. Those are the only benefits I can see.

Could you get us a measurement of length from the crosspin to the edge of the cover mounting surface please?

5.48" Its currently lying in the rain behind a barn where I found it. The 8.5 (especially the 28-spline version) is a turd. Forget it. Move on.

I attached a picture of the HP dana 30 we are working on for chevrolet S10 zr2 trucks and blazers.

Cute. D30s have a legendary rep...but only in XJs. I think the real issue is going to be oil-pan clearance...regardless of the axle. That D30 will certainly fit...pound for pound probably the strongest diff out there. However, I'm not sure it would take the abuse of 37" tires, 5.13 gears, and 6000 lbs of full-frame truck...especially with a V8.

 

[atvspeed4]

More excuse to run a 8.6 from the rear of an H3.


Oh it matters. The 8.6 comes with an Eaton locker, matching 4.56 gears, and 30 years of improvements. You can cut the ends of the tubes off and re-weld them within inches of the pumpkin, you can use modern late model seals and bearings...easily available, it already has C-clips, and the spline count/shaft size is a vast improvement over anything else in its size range. Those are the only benefits I can see.


5.48" Its currently lying in the rain behind a barn where I found it. The 8.5 (especially the 28-spline version) is a turd. Forget it. Move on.


Cute. D30s have a legendary rep...but only in XJs. I think the real issue is going to be oil-pan clearance...regardless of the axle. That D30 will certainly fit...pound for pound probably the strongest diff out there. However, I'm not sure it would take the abuse of 37" tires, 5.13 gears, and 6000 lbs of full-frame truck...especially with a V8.

http://www.my4by.com/gm-10-bolt-8.5-inch-vs-8.6-inch.html

We will be starting from scratch with the housing and making custom shafts. As I had mentioned the only difference between the 8.5 and 8.6 is the carrier bearing size. But yes we wanted to use the 8.6 for larger carrier bearings.

I would not put the dana 30 in the h3, I was just showing another project we are working on for a different vehicle. Just showing we are not just another voice but actually get our hands dirty and build this stuff!

Hopefully we can all put our minds together and figure this out!

 

[06 H3]

You can pull an H3 rear diff and start chopping it without worrying about running reverse gears and such? I read somewhere that a buggy took a rear Dana80 and modified it for the front but they had to flip it. Does that apply?

 

[atvspeed4]

You can pull an H3 rear diff and start chopping it without worrying about running reverse gears and such? I read somewhere that a buggy took a rear Dana80 and modified it for the front but they had to flip it. Does that apply?

Nope no flipping it and if you did that with most diffs I believe there would be an issue with oil reaching the pinion. Almost all low pinions run on the coast side of the gear in a front application, even our stock diffs do.

I'd love to chop a h3 diff down but they are very very expensive new or used. I found one in Texas for $950 though shipping would be a killer for me to Massachusetts.

 

[jakesz28]

I think you can find a 8.6 out of plenty of other vehicles cheaper.

 

[06 H3]

Is the 8.6 coast side?

 

[MaxPF]

These axles are considered to be the wimpy replacement for the D44,

They are considered wimpy replacements for a 44 only by the ignorant and misinformed. The fact is, the 10b center section is superior to the D44. Both are 8-1/2" ring gear designs, but the 10b carrier has wider bearing spacing which gives improved support. More importantly, the inner pinion bearing is MUCH larger in the 10b. Overall, the 10b suffers from less ring and pinion deflection and greater pinion bearing durability vs the D44.

The main weak point on 10bs are weak stock carriers, but this is a weakness shared by the D44 as well. Older 10b axles used 28 spline shafts, but they have been 30 spline since the late 80's. The carrier issue is solved when you use any limited slip or locking carrier (except for the G80 "gov-lok", which are known to break under abuse).

Overall, if using a center section to make a new IFS center, the best bet are later 10b rear centers, since they use larger carrier bearings. Next would be the early front centers.

If contemplating a SAS, the 10b front is a fine axle, but none of them came with flat top passenger side knuckles (needed for crossover steering) and most were 28 spline. They are easy to convert to 30 spline, and any D44 knuckle will work on the 10b axle (the inner C's and outer components are identical between 10b and D44s). The only advantageous D44 are some of the 3/4 ton axles that have 1/2" wall tubes (standard D44 and all 10b axles are 5/16" wall tubes), but if your application is that abusive you are going to end up with ball joint and other issues, so you would be better off with a D60.

FWIW, I have a 10b front axle with no gears, a late open 10b carrier (they work in the early housings when used with the proper bearings), flat top knuckles, a crossover arm, full steel backing plates, TWO complete sets of 30 spline shafts, and other odds and ends. Basically, everything except gears to do a 10b SAS on an H3. If anyone is interested, PM me. I will even install and set up gears of your choice

 

[MaxPF]

I dont think it would matter if we started with a 8.6 vs an 8.5....

The 8.5 and 8.6 are essentially identical axles. They use the exact same ring and pinion sets and the same carriers. The only difference is the housing, which is designed for larger OD carrier bearings. Carriers from early and late housings are easily interchanged, as suitable bearings are available for such swaps.

To repeat, the "8.5" and "8.6" do NOT use different gear sets. It is nothing but a nomenclature change by GM to identify a later, revised housing design. From my experience, the later axles are no more or less durable than the early units.

 

[06 H3]

Thanks for chiming in max! I'm more interested in keeping the ifs for now with the 10b centersection. I may pick up an axle and start investigating myself. As for width, I'm trying to keep it to a minimum so I don't need to make new longer control arms and such. With a 10b rear chopping it making custom flanges and c clips my main confusion is axle seals. Is there any main things Id have to do? Is it just a bearing retainer and seal? I'm kinda new to the seal and bearing deal.

Chopping up my own 10b is fine and even setting up gears. It's making sure axle plunge is correct, setting up seals and mounting (which I have a few ideas)

 

[4speedfunk]

In any normal SA application the wide bearing spacing of the 10-bolt is a plus. But its a handicap for what we're trying to do...very little room under the H3, and by the time you add a bearing, seal and flange to the IFS...its gonna get wide (maybe too wide). Hopefully the shorter 1500 half-shafts will allow you to keep it out of the oil pan.

While the 8.5 and 8.6 share the same ring-gears...I noticed the late-model 8.6 housing under the rear of the H3 is clearly a cleaner, beefier casting. Perhaps this is due to modern CNC manufacturing process rather than 70's slide-rule technology?...I'm not sure. But it makes sense to me to use the latest, most advanced parts you can find. I would think that after 35 years...the H3's 8.6 probably has quite a bit of improvements built into it that might not be obvious to the naked eye. The pumpkin is cast without the leaf-spring perch, which may actually benefit somebody trying chop and add a bearing/seal to it. At first, I thought having the extra meat of the perch might help, and you could use it to support a bearing. But after cutting apart a front 10-bolt housing and looking closely at it...I think the smaller RWD pumpkin might allow for easier chopping. Try to use the tube if possible, rather than milling deep into the casting. I don't see a problem running this axle in the front position. As someone else pointed out...all the low-pinion stuff runs on the coast-side of the teeth anyway, and they've been doing this for 50 years. I have no idea what effect this would have on a used gear-set (that had been previously ran in the other direction)...but, its worth a try.

I wouldn't complain about $950 for one of these. Remember, you're saving a grand by having the E-locker and matching gears already installed in it. Not only that but, all of your bearings, seals, and set-up is already done for you. You can simply un-load housing...do the chop...clean it up...and put everything back it the same position. I say this only because its a "prototype", and everything at this point is experimental. You can always do a re-gear to both axles after testing your IFS with stock gears.

 

[backcountryislife]

Remember, you're saving a grand by having the E-locker and matching gears already installed in it. Not only that but, all of your bearings, seals, and set-up is already done for you. You can simply un-load housing...do the chop...clean it up...and put everything back it the same position. I say this only because its a "prototype", and everything at this point is experimental. You can always do a re-gear to both axles after testing your IFS with stock gears.

Would you really go through all the trouble of this though, and leave the stock gears? I wouldn't even start the project with them in there. That would be my main reason to go this direction, is the ability to gear down. The E locker being there is a big plus though.. shoot, that alone is a hefty chunk of change, and like the gears, doing this without adding the locker would seem wasteful.

 

[06 H3]

I think I would if I was building/prototyping. Why spend money to regear the back and then have possible issues. Once it's proven and true then go regear and sell future ones with whatever gear ratio they want

 

[bebe]

Just so you guys know - re-gearing the rear end in these is a Pita - do it once. If you remember, we had to do some dental work to get the cross pin in on the 5:13's. That will add to the cost. It's tedious and time consuming. (For those who won't be doing it themselves).

The housing we used, by luck was a HD D44. We looked at the HP D44 TTB and it would have been perfect, but we didn't want to mess with tubing it.

The front is also a 35 spline ARB, with Cry-o treated star splined chomoly stub shafts.

 

[06 H3]

yea I remember the same thing happening to CJ when he did his 5.13 gearing. There are some youtube videos on doing that IIRC. If using the stock crossmembers its best we stay with a LP axle as the HP adds more issues with clearance.

 

[4speedfunk]

Forgive me...I'm still stuck in the "prototype" mode, when thinking about this. If I knew ahead of time that the custom IFS would work for sure...I would totally swap to 5.13s during the build. But, it would be a damn shame to swap out both sets of gears, only to find that the IFS didn't go as planned. Swapping your stock AAM-7 back in as a temporary axle would not be an option. So, thats why I was thinkin about re-using the stock parts & gearing until you get it all hashed out.

I didn't think swapping the rear gears was too tough. Grinding the tooth took me all of 10 minutes with a die-grinder, once I found out that was the fix (thanks Bebe). A bigger hassle was simply getting the axle shafts out! The ABS rings are glued onto the axle shafts about 6" from the ends, and they don't pull-out like normal C-clip shafts. I recommend prying them out from inside the window of the carrier...and not from the flange end. I destroyed both of my axle seals with a pry bar. No biggy...my GM dealer had the seals in stock but, in retrospect...if you pry at the C-clip ends, you won't mangle the seals out at the ends of the tubes. Once you get the shafts out...you get to wrestle around with the actuator coil on the Eaton locker. You have to sort of disconnect it and leave it in place, so you can pull the carrier out. Its not too tough...but a second set of fingers helps. After that...its pretty much a normal gear-swap.

 

[bebe]

So, overall this is what I have in my mind....and I know my day has passed but I still think that you all can benefit from how we did the IFS upgrade in my H3.

This was one of the inspirations for what we ended up doing. This being one extreme and digger being the other.

Currie will also tube either side and add the bearing retainer and seals. But honestly the possibilities are endless as far as application goes.

 

[rsc]

Oh. My. God! Go big or go home, right?