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The Jana gear upgrade thread

Lil'John

Lil'John

Former #278
Joined
May 20, 2020
Member Number
488
Messages
1,142
Loc
Walking to the Rubicon
I'd like to talk about the Jana gear upgrades available from Jantz. Here is the Jana76 set:
http://jantz4x4.com/jantz.php?p=detail&pro=jana_76

I understand some of it and recall a thread on the other site but I'd like to start fresh here.

What is the good and the bad with going this route for gear strength?

I'm considering going this route for 5.38 and/or 5.86 gears. The 5.38 gears would be in a Ford e350 Dana 60 rear axle behind an unknown HP turbo 5.3L, 4l80e trans, and a doubler on top of 43" tires:grinpimp: The 5.86 gears would be in similar rear axle and/or Dodge KP Dana 60 front behind 472 cady and sm465 on top of 35" tires. The rear Dana 60 is a smooth bottom center section. Both rigs will be Rubicon run in a leisurely technical manner... no KOH or other rock racing type wheeling.

My concern with either gear set(5.38 and 5.86) in a Dana 60 is whether the pinion becomes a failure point.

Is it better to start up front? Or with the rear axle?
 
I've talked with him on the phone a few times, pretty awesome guy.

When starting from scratch his kit isn't far off an install kit, then most D70 parts are similar in cost to D60, so it's kinda why not.

The only bummer is that the pinion spline is the same size. I doubt you will be pushing the limit of that though.

Also, there are no 5.38s made for a D70, sounds crazy, because they go from 3.07 to 7.17s, but it's true. Jantz told me he wished he would have spent the $100k to have 5.38 D70 gears cut years ago. :laughing:



*in before someone links curries D70 HP 5.38s :flipoff2:
 
YotaAtieToo said:
I've talked with him on the phone a few times, pretty awesome guy.

When starting from scratch his kit isn't far off an install kit, then most D70 parts are similar in cost to D60, so it's kinda why not.

The only bummer is that the pinion spline is the same size. I doubt you will be pushing the limit of that though.
Click to expand...
Currently I only have one set of 5.86 gears for the D60. So I was considering this route.

YotaAtieToo said:
Also, there are no 5.38s made for a D70, sounds crazy, because they go from 3.07 to 7.17s, but it's true. Jantz told me he wished he would have spent the $100k to have 5.38 D70 gears cut years ago. :laughing:
Click to expand...
Well fawk... I knew there was something I forgot from the last time I looked at this 2-3 years ago for the 5.38 project:homer: The front on that project is a HP 60 so maxed out at 5.38 :(
 
Lil'John said:
Front is done with ARB. :homer:
Click to expand...

We just went through a similar ordeal with my father in laws jeep. Had 60s with 5.38s, he bought a basically 500 hp 6.2ls and it has 42s, when I found the rear axle was bent, it was time to consider something bigger. I was going to use the d70u I had here, but the 5.38 dilemma ended that(even called jantz about a jana87) He also had a E350 D60u, but I couldn't see putting all that into a D60 rear for the given rig. Ended up with a shaved 14b like everyone else.:laughing:

I don't think the 43s,v8 and D60 rear will last long, a minor shaved 14b is maybe 1" less clearance than a 60. If you go all out with the shave, it has more.

I like those d60u's, I have one under my build, but it's 125hp maybe. :flipoff2: it just would suck to build it all up, especially when you need new shafts for 35 spline, only to blow it 8n the middle of nowhere.
 
I have some 5.86 Dana 60 Gears out of a Zamboni (OE SPICER) I won't be using (I'm doing the 4.56 Jana 44 w. 35" rubber and an SM465). I'm on the east coast but willing to ship them, sent a lot of Willys parts out to California over the past several months. PM me if interested
 
YotaAtieToo said:
We just went through a similar ordeal with my father in laws jeep. Had 60s with 5.38s, he bought a basically 500 hp 6.2ls and it has 42s, when I found the rear axle was bent, it was time to consider something bigger. I was going to use the d70u I had here, but the 5.38 dilemma ended that(even called jantz about a jana87) He also had a E350 D60u, but I couldn't see putting all that into a D60 rear for the given rig. Ended up with a shaved 14b like everyone else.:laughing:

I don't think the 43s,v8 and D60 rear will last long, a minor shaved 14b is maybe 1" less clearance than a 60. If you go all out with the shave, it has more.

I like those d60u's, I have one under my build, but it's 125hp maybe. :flipoff2: it just would suck to build it all up, especially when you need new shafts for 35 spline, only to blow it 8n the middle of nowhere.
Click to expand...

As noted, hard but technically wheeled ;) I made stock minitruck birfields survive a 5.0L TBI in an FJ40:homer:

The 43s will be a relatively light fullbody rig:
side1_sml.jpg

Ignore the FJ40 tub off the back... temp storage ;)
 
I am here ask away :) Carl Jantz
To be clear, 5.38s are available for the high pinions only, and they come with a 35 spline pinion shaft, plus are a bit bigger in diameter, so they are Super 70s at 10 5/8" diameter, plus they have a wider back face for more load bolt contact.
Also available in 35 spline pinion are the 4.88 High pinion super 70 gears as well.
 
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Mr Stubs said:
Its been quite a while since I’ve been to your shop, hope all is well. I will say that the load bolts that you put in my 9.5 thirds way back when have made those thirds unbelievable.[/COLOR]
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Glad to hear, I have always wondered if we kept the gears from breaking if the pinion shaft was next, have you had any of those fail?
 
Superjeep said:
Glad to hear, I have always wondered if we kept the gears from breaking if the pinion shaft was next, have you had any of those fail?
Click to expand...

No.

The crawler (Skittles) is 3250lbs. It’s running 39.5 reds with close to 300 extra lbs per tire worth of water in them.
 
Superjeep said:
I am here ask away :) Carl Jantz
To be clear, 5.38s are available for the high pinions only, and they come with a 35 spline pinion shaft, plus are a bit bigger in diameter, so they are Super 70s at 10 5/8" diameter, plus they have a wider back face for more load bolt contact.
Also available in 35 spline pinion are the 4.88 High pinion super 70 gears as well.
Click to expand...

About $500 per set? The 76 kit to put those in a hp60 housing isn't as straightforward either correct?
 
YotaAtieToo said:
About $500 per set? The 76 kit to put those in a hp60 housing isn't as straightforward either correct?
Click to expand...

No more work to do it, it just cost more because of the price of the bearings, the included 35 spline yoke ( available in 1310,1350,1410 or 1480) , plus the 35 spline pinion preload kit.
 
Superjeep Thank you for stopping by.

Do you think the smooth D60u housing out of a e350 van would be too thin in the bottom for a 76 kit?

In your opinion, is the front or rear axle the best place to start with a 76 kit?
 
Lil'John said:
Superjeep Thank you for stopping by.

Do you think the smooth D60u housing out of a e350 van would be too thin in the bottom for a 76 kit?

In your opinion, is the front or rear axle the best place to start with a 76 kit?
Click to expand...


I'm running a E350 D60 housing w/ Carl's D70 kit in my 4500 car. I may not be the best judge of strength as we're only 4k lbs race ready, but 500HP, 37" tires, and I do NOT drive it easy and haven't broken any ring/pinion stuff yet.

danny1.jpg
 
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