After coming up with The Jana kits* to install larger gears in smaller housings, a question arose. Will the housings be able to stand up to the 33% - 44% higher torque loads? Well the fact of the matter is No, in fact the stock housings don't even hold in the stock gears well, and that is why after market differential housings are made with thicker castings, and massive billet bearing caps. You will also find many companies offering Billet bearing caps to be installed in stock housings, and cast Aluminum differential covers with load bolts to prevent bearing cap failure. Just Google "differential girdle billet caps" and you will find dozens of them used in all types of race cars. A little research will confirm that a major contributor to gear failure is housing deflection, when the gears don't line up they wear more, and break. If you look a gear that has been under heavy use like in an overloaded tow vehicle you can see two wear patterns, one from driving unloaded and one from driving overloaded. Even Toyota is now using a one piece bearing cap girdle in their larger trucks to prevent gear defection.
So I decided to combine a couple of ideas to improve the reliability of gear sets. Start with 3/8" thick diff cover, add to it the load bolts, and also add a stud girdle system to tie it all together. After all any good stroker motor has rocker arm girdles and a main cap girdle to keep its parts in line, so why not do it for differentials as well. Pictured here are covers for Jana 54 /k4 , and Jana 76.
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Covers come with Grade 8 studs. The studs are installed in the main bearing caps, then a Grade 8 nut is torqued down (80 Ft-lbs) holding the cap in place and then the stud girdle is placed over the studs, with stanchions that go through the cover sitting on the nuts, then nylock nuts are torqued down over the studs, then c-sunk cover bolts lock it all in place . Then the load bolts are installed to 5 Ft-lbs (60 in-lbs) putting pressure on the caps to prevent deflection.578445

The bulges in the cover are where we heated it up and formed it for clearance for the larger ring gear.
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Use no gasket, seal all mating surfaces & threads with Permatex "The Right Stuff".

If you found this thread you'll also be interested in our full product line of Differential Hybrids;

HOW TO INSTALL:
D70s into D60s, Jana 76:http://pirate4x4.com/forum/showthread.php?t=946421
D50 into D44s, Jana 54:http://pirate4x4.com/forum/showthread.php?t=948996
New 8.9" JKs into 44s Jana K4:http://pirate4x4.com/forum/showthread.php?t=957491
D80s into D70s, Jana 87: http://pirate4x4.com/forum/showthread.php?t=958266

I start with Ruff Stuff covers and bore through them to put in the Stanchions, Their covers come milled flat after welding and the cover bolt holes line up well. If you already have a HD cover I can convert it for you, steel or Aluminum. Here is a factory 1/8" thick cover with brackets welded to it that act as a rock guard and 3 link mount.
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The inside of the cover showing the stanchions and modification to clear the larger ring gear.
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I couldn't resist this, Here is a picture of my Wife milling the Hexes on the girdle studs. She's smiling because she likes making long hard studs.

Originally I never saw the need for this, I never had a 44 or 60 bearing cap fail on me. Although I have seen several Ford 9" caps broken right in 1/2. But when pirate member jsawduste asked me how the housings would hold up I began thinking. I'd seen several spun bearings, yet the bearing still looked fair, why were they spinning? Because the caps had stretched out, and although I had never had a spun bearing myself, with all the ring & pinions I had broken I saw fretting (wear) between the bearing cap and housing at the parting line. The only way these can wear is if there is relative motion between the two mating parts.
jsawduste was a engineer in the Differential division of GM for 30 years, He brought up the fact that housings are spreadable, in fact many manufactures use a housing spreader for assembly. Also he told me you just wouldn't believe how much deflection housings go thru when torqued on but he had seen it on their test benches with dial indicators placed at critical locations on the housing. Which let to the following:
jswasduste and I just had very enlightening discussion. What I came to realize is that even though the housings and bearing caps may not fail, they still will defect quite a lot, so that ring and pinion life is greatly reduced and this is happening more than we want to know even in stock differentials as we put them to the max offroading. Its not like I didn't know this before but now I understand the implications more. When you are setting up a diff you take hours getting the pinion depth correct, shimming it a few thousands this way or that way until the tooth contact pattern is correct and some guys even set the contact area a little to the inside to allow the contact to be more even under a load. jswasduste mentioned how much a diff deflects when you put a housing spreader in it so I did some Rough calculations based on that Idea.
Based on my housing spreader dimensions, bolt size and thread pitch and the amount of torque on that bolt to spread the housing, I calculated (in round numbers) it takes 20,000 lbs force to spread it the recommended amount of .015" for carrier preload during assembly. Lets compare that force to the force between the ring and pinion under full load. If an aftermarket 35 spline axle can just handle 10,000 ft-lbs torque then if you have a 5 to 1 ring and pinion (keeping the math simple) then you are inputting 2000 ft-lbs torque at the pinion (neglecting friction). The mid point of tooth contact on a 5-1 gear set would be about 1 1/4" out from the center of the pinion. So 2000 ft-lbs torque is 2000 lbs force acting at 1 foot, but 2000 ft-lbs is 19,000 lbs force acting at 1 1/4". So if 20,000 lbs force deflects the housing .015" Then 19,000 lbs force could easily deflect the ring and pinion apart .010-.020".
So now we know why the big after market differential housing manufactures really beef up the thickness, and webbing, of the diffs. Now the cool thing is that I don't see any reason we can't beef them up as well. All it will take is welding on some extra ribbing around the pinion to support it, just like Ford 9" after market housings have extra ribs cast horizontally and vertically into the 3rd member. Add to that stud girdles and billet caps and you just might be stronger than going bigger at a fraction of the cost.

you have a picture of it with the cover off?

you have a picture of it with the cover off?
Installation starts with bottom taping the carrier cap bolt holes, then installing the Grade 8 studs, and torquing on nuts to hold the caps in place. I made an extra deep socket to do this by grinding a hex on the drive end of a 3/4 deep well socket to make it look like a spark plug socket, then I double stack a another deep well socket on that to torque the nuts.
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Here are the stanchions in place over the studs, then the cover is bolted on over this and the stanchions welded in place.
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I thought about making a cut away part for demo but haven't convinced myself to saw one in half so this dwg will have to do. (I just noticed this dwg does not show the carrier cap load bolt bosses in-between the carrier bolt stanchions, I'll fix that soon but to late tonight, I'll make a cut-away dwg of the assembly for clarity) meanwhile you can see nothing protrudes out past the periphery of the cover to get in the way of tie rods. I can also provide longer studs for attaching steering ram mounts, 3 link brackets or back braces.

578766

This is awesome. You should get with Ballistic or Ruffstuff, etc and see if you can get these covers manufactured for you then you could sell it all as a "kit" from the gears all the way to the special cover to finish it off.

This is awesome. You should get with Ballistic or Ruffstuff, etc and see if you can get these covers manufactured for you then you could sell it all as a "kit" from the gears all the way to the special cover to finish it off.
Just got off the phone with Dan at Rough stuff this morning, and suggested to him that they put my/our girdles on his web site, They are set up to sell and then their bookkeeper just tells me where to ship. Please let Dan know this is a good idea, while he is pondering it.

Just sent him a PM. Thanks!

Bitchin' setup!!

Where on the bearing cap does the girdle stud land? Some of the caps have numbers and stuff cast into the top, would this lead to the stud having issues contacting nice and flat on them? Would it be advisable to machine a flat spot on top of the cap?


Prices? I already have a RS cover, price on having you add this to it?

Bitchin' setup!!

Where on the bearing cap does the girdle stud land? Some of the caps have numbers and stuff cast into the top, would this lead to the stud having issues contacting nice and flat on them? Would it be advisable to machine a flat spot on top of the cap?


Prices? I already have a RS cover, price on having you add this to it?

Install a kit in your after market cover steel or aluminum $150.
Machining a flat spot, well glad you reminded me I forgot to get a good picture of that and put it in the instructions. I also think it could be done with file and some gear marking compound. just file till you get an even pressure spot.

Bitchin' setup!!

Where on the bearing cap does the girdle stud land? Some of the caps have numbers and stuff cast into the top, would this lead to the stud having issues contacting nice and flat on them? Would it be advisable to machine a flat spot on top of the cap?


I hand filled these flat as they had large numbers cast in the top, It took all of about 8 minutes. I was trying to figure out how I would know when they were flat enough besides installing them, and doing a contact pattern with gear marking compound several times. By putting them on a flat table and lining them up with a vertical line in the back ground (like a door Jamb) in two directions I could tell right off when they stood up straight the were ready for a check fit. And by filing just down the middle I removed no more material than to get to the bottom of the raised cast numbers thus no strength loss.

I think this is a great idea for those with big horsepower and big tires with a heavy right foot. I'm running an hp60 front and back and will be running around 450hp. I'm concerned my rear hp60 won't last long. I've picked up a set of chromoly carrier bearing caps and had my ring/pinion cryo'd to try and delay failure. I already have a 3/8 cover and think this may be the icing on the cake as far as maximizing what I have. I could do the d70 gear swap but I've already got new gears and cryo'd. Hmmmm......

I think this is a great idea for those with big horsepower and big tires with a heavy right foot. I'm running an hp60 front and back and will be running around 450hp. I'm concerned my rear hp60 won't last long. I've picked up a set of chromoly carrier bearing caps and had my ring/pinion cryo'd to try and delay failure. I already have a 3/8 cover and think this may be the icing on the cake as far as maximizing what I have. I could do the d70 gear swap but I've already got new gears and cryo'd. Hmmmm......
What gear ratio are you running now. Remember 5.13s are the only available High pinion 70 gear sets available currently. However I have it from and inside source that some manufactures will be doing HP 5.38s & 4.88s with 35 spline input within the next year. So hopefully yours last that long.

What gear ratio are you running now. Remember 5.13s are the only available High pinion 70 gear sets available currently. However I have it from and inside source that some manufactures will be doing HP 5.38s & 4.88s with 35 spline input within the next year. So hopefully yours last that long.

When you say 35 spline input are you talking about the pinion shaft splines? That would be kickass!

when you say 35 spline input are you talking about the pinion shaft splines? That would be kickass!

yes!

http://www.rebelrockrunners.org/andrew/mbp/oh_my_fuck.gif

What gear ratio are you running now. Remember 5.13s are the only available High pinion 70 gear sets available currently. However I have it from and inside source that some manufactures will be doing HP 5.38s & 4.88s with 35 spline input within the next year. So hopefully yours last that long.


I hate to even say but 4.10's in the diffs at the moment. The rig is torn down completely getting a full redesign. It was a budget thing at the time of the build. I'm sure my 5.13's will last a year as I don't expect to have it back up and running by then..:p.

I would be curious to know of your GM buddy that's familiar with the housing flex points under load and designing a truss system that structurely reinforces it to decrease the flex in relation to deflection. Or, one could just run a Jana76 and call it good.:D

So is the purpose of the bearing cap bolts incorporated into the cover to tie it all together for further housing rigidity? I don't see how that is really that necessary. I get the cap preload bolts thing.

I would be curious to know of your GM buddy that's familiar with the housing flex points under load and designing a truss system that structurely reinforces it to decrease the flex in relation to deflection. Or, one could just run a Jana76 and call it good.:D

So is the purpose of the bearing cap bolts incorporated into the cover to tie it all together for further housing rigidity? I don't see how that is really that necessary. I get the cap preload bolts thing.

After talking with the GM guy he said to get all the available advantage of the 70 ring gear me must prevent deflection in all directions, we should add more webbing to the pinion support, similar to stock 9" third members which have 1 vertical rib and 3 horizontal ribs, yet the after market one use larger bearings, thicker castings and have 2 vertical ribs and 5 horizontal ones. I think 1/4" webs welded in-between the webs that are there would help. Then some of the Tennessee HP boys I've talked with say the have pushed the bearing caps apart and right out of the housings so the girdle should take care of that. and ultimately a billet carrier cap on the ring gear side would help as per Mark Williams and a host of drag racers.

After talking with the GM guy he said to get all the available advantage of the 70 ring gear me must prevent deflection in all directions, we should add more webbing to the pinion support, similar to stock 9" third members which have 1 vertical rib and 3 horizontal ribs, yet the after market one use larger bearings, thicker castings and have 2 vertical ribs and 5 horizontal ones. I think 1/4" webs welded in-between the webs that are there would help. Then some of the Tennessee HP boys I've talked with say the have pushed the bearing caps apart and right out of the housings so the girdle should take care of that. and ultimately a billet carrier cap on the ring gear side would help as per Mark Williams and a host of drag racers.


Perhaps a chryo'd d70 gear set stuffed into a d60 with the reinforced bearing cap cover and additional pinion support is in my future. I always say, do it right, do it once. I'm no expert on axles but I love the idea. And my rig is in redesign stage with no timeline in mind.....

Are the bearing caps the same between d60 and d70?

Are these covers available now through ruffstuff or through you? I checked ruffstuffs site and didn't see them. I am not ready for one yet but will be.

Are these covers available now through ruffstuff or through you? I checked ruffstuffs site and didn't see them. I am not ready for one yet but will be.
Just through me, I'm doing batches of his covers for sale, and also converting customers covers over for those that already have an aftermarket or home made monster. I asked Dan a ruff stuff about selling them on his site, and he said he would think about it.

If I ordered one of these setup for the J76, could I use it on my 60 gears until they break and make the upgrade to the 76 parts? I don't want to have to buy this twice if there are differences between the two.

If I ordered one of these setup for the J76, could I use it on my 60 gears until they break and make the upgrade to the 76 parts? I don't want to have to buy this twice if there are differences between the two.
these will fit stock or Jana'd in all cases.

Great idea.

Install a kit in your after market cover steel or aluminum $150.
For those that haven't purchased diff covers yet, what's the price for the complete cover girdle package (including a RuffStuff cover)?

for those that haven't purchased diff covers yet, what's the price for the complete cover girdle package (including a ruffstuff cover)?

$275.00

After talking with the GM guy he said to get all the available advantage of the 70 ring gear me must prevent deflection in all directions, we should add more webbing to the pinion support, similar to stock 9" third members which have 1 vertical rib and 3 horizontal ribs, yet the after market one use larger bearings, thicker castings and have 2 vertical ribs and 5 horizontal ones. I think 1/4" webs welded in-between the webs that are there would help. Then some of the Tennessee HP boys I've talked with say the have pushed the bearing caps apart and right out of the housings so the girdle should take care of that. and ultimately a billet carrier cap on the ring gear side would help as per Mark Williams and a host of drag racers.


What are your ideas on adding more webbing to the pinion support area?

I have a Chevy front d60 running a 1.5" tie rod in the stock location. Will the cover fit as is or does the tie rod have to move (ie; hi steer)?

I have a Chevy front d60 running a 1.5" tie rod in the stock location. Will the cover fit as is or does the tie rod have to move (ie; hi steer)?

its going to kiss it a full lock. Now then are you steering to the factory stops, that's about 30 degrees each way. I have an 1 1/4" tie rod, and and my steering stops have been backed off to 35 degrees each way. As I approach maximum steering the tie rod kisses the cover and bows out about 1/8" I was worried about this but it has not caused an issue in 5 years other than a spot of rust. I don't even feel it in the steering wheel. However I did just recently see some offset tie rod ends on the Rough stuff web site. you could also purposefully bow the tie rod slightly.

What are your ideas on adding more webbing to the pinion support area?

I would make some templates, and weld ribbing/ gussets similar to the factory ones in between the factory ones.

In Stock now are Jana Girdles for the Ford Sterling 10 1/4 & 10 1/2" Differentials. I started with Ruff stuff covers, so you know these are the Best.

For you Drag race guys I have built a few light weight Aluminum Girdle covers. I start with LPW's Ultimate 60 cover which already comes with jack bolts for the carrier caps and add bosses for the thru carrier bolts. The LPW covers already come larger to hold more oil so very minimal grinding was required to clear the D70 ring gear as seen in the partially complete cover on the left. The LPW cover also come with mounting holes for there back brace system, or I'm sure any other back brace could be fabbed to it. Jana 76 covers can also be used to upgrade a standard DANA 60 rear end.

Hey Carl,

I wanted to know if it is possible or worth it to do some of this with a cast cover?

I am currently running an Ox locker, with its own cast cover which activates the locker. I was thinking of going with the Jana JK44 kit (I have a low pinion front) with billet bearing caps, and they trying to do the girdle or cap load bolts just by drilling and threading the cover. Possible?

Hey Carl,

I wanted to know if it is possible or worth it to do some of this with a cast cover?

I am currently running an Ox locker, with its own cast cover which activates the locker. I was thinking of going with the Jana JK44 kit (I have a low pinion front) with billet bearing caps, and they trying to do the girdle or cap load bolts just by drilling and threading the cover. Possible?

You wont be able to just drill and tap the cover, as you need the bosses for the long carrier bolts to clamp down thru. I can provide a do it yourself kit. With the OX locker shift actuator you will not be able to get the Jack bolt on the right side of the cover but thats OK as its the left bearing that get the most load. Here is what the Rockcrusher cast cover looks like.