Dyantrac Front Hybrid - 60/44

jk12blk

jk12blk

New member
Dynatrac is making me the following custom build (great fit for my use case).
I wanted a stronger axle assembly compared to my factory dana 44, but I did not want to deal with swapping out my ATX Slab 5x5 wheels for full 60.
Prorock 44 was an obvious choice or the Currie 60/44 hybrid.
If Currie can do a 60/44 hybrid, why not Dynatrac?
So I asked Dynatrac and they came up with the following build below (first ever)....

Dynatrac Pro Rock 60/44 Hybrid Partial Front Axle Assembly w/ARB Air Locker - 07+ Jeep JK
- *Custom Machined Dynatrac Pro Rock 60 High Ground Clearance (Reverse Cut) Heavy Duty Nodular Iron Housing
- Heavy Duty 3.125" Diameter, 1/2" Thick Wall DOM Housing Tube Assemblies, Installed
- Dynatrac Pro Rock 60 Heavy Duty Nodular Iron Powder Coated Differential Cover, Installed
- Stock JK Axle Width - 65.5"

Coupled with a 35 spline RCV inner/32 outer, and 35 spline ARB, should be good to go with 60 gears.
One potential "gotcha" is the tie rod clearance lock to lock.
Fortunately, a local fab shop ensured me this will not be a problem.

Ready to pull the trigger Monday.

My JK weights 6400 lbs and will never exceed 37" tires.

Rear will be Dynatrac semi float Prorock 60 - 35 spline axles and ARB.

ready to get this party started!
 
Yep. Trying to make as strong can be without swapping wheels. Weak point may be at factory outer knuckle or wheel. Seems like a good idea for a few (slightly more) hundred extra bucks. :)
 
Are you saving a lot of money over just buying a PR 60? Seems a little nutty if the only reason you're doing this is so you don't have to buy new wheels. :thinking:
 
suicideking said:
Are you saving a lot of money over just buying a PR 60? Seems a little nutty if the only reason you're doing this is so you don't have to buy new wheels. :thinking:
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After running the numbers, conservatively, probably still 3,000-3,500 less than a typical PR 60 (a PR60 without a lot of upgrades too). I was going PR44, but I had to ask the question knowing Currie had it available. In the end, it was not much more, so why not? Sure, it added a few bucks but now I have a PR 60 housing and gears. And the PR44 end forgings are apparently beefier than the PR60 end forgings. It could be nutty, but what the hell - seems like a good design. :eek:)

There will be added costs for the custom tie chromoly rod fab (no idea what that will be).
Also, my Adams drive shafts need to be reworked for 1350 - more $.

I fat fingered my JK weight. It is actually 5400 lbs (weighed it on the local dumps truck scale). I only mention this because Dynatrac took both my tire size and weight of my vehicle when deciding on the rear PR60. semi float was plenty for my JK. I will not run tires larger than 37 (famous last words). :eek:)
 
jk12blk said:
After running the numbers, conservatively, probably still 3,000-3,500 less than a typical PR 60 (a PR60 without a lot of upgrades too). I was going PR44, but I had to ask the question knowing Currie had it available. In the end, it was not much more, so why not? Sure, it added a few bucks but now I have a PR 60 housing and gears. And the PR44 end forgings are apparently beefier than the PR60 end forgings. It could be nutty, but what the hell - seems like a good design. :eek:)

There will be added costs for the custom tie chromoly rod fab (no idea what that will be).
Also, my Adams drive shafts need to be reworked for 1350 - more $.

I fat fingered my JK weight. It is actually 5400 lbs (weighed it on the local dumps truck scale). I only mention this because Dynatrac took both my tire size and weight of my vehicle when deciding on the rear PR60. semi float was plenty for my JK. I will not run tires larger than 37 (famous last words). :eek:)
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Sounds like a good in between, especially since you don't plan on going past 37s.
 
I guess my question is, if it has a 60 diff and 44 tubes, what spline are the shafts?
 
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Berzerker said:
I guess my question is, if it has a 60 diff and 44 tubes, what spline are the shafts?
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It is actually their 60 tubes which they will mill down the ends a little for PR 44 end forgings. Here is the complete build...

Dynatrac Pro Rock 60/44 Hybrid Partial Front Axle Assembly w/ARB Air Locker - 07+ Jeep JK
- *Custom Machined Dynatrac Pro Rock 60 High Ground Clearance (Reverse Cut) Heavy Duty Nodular Iron Housing
- Heavy Duty 3.125" Diameter, 1/2" Thick Wall DOM Housing Tube Assemblies, Installed
- Dynatrac Pro Rock 60 Heavy Duty Nodular Iron Powder Coated Differential Cover, Installed
- Stock JK Axle Width - 65.5"
-Dynatrac JK Pro Series 44 Extra Strength Heavy Duty End Forgings, Installed
-Synergy Suspension HD JK Ball Joints, 2 Uppers & 2 Lowers, Sourced & Installed – UPGRADE
-Dynatrac Jeep JK Pro Series 60 Heavy Duty Fabricated 3/16" Coil Spring Suspension Bracket Assemblies, Installed
-Dynatrac JK Raised Track Bar Bracket Modification w/Ram Assist Tabs (For High Steer/Flipped Drag Link Applications) – UPGRADE
-ARB Air Locker Differential, D60, 35 Spline, Installed, w/ARB Kit
-D60 Ring and Pinion, 5.13 Reverse Cut, Installed
-1310 U-bolt Input Yoke, D60, Installed, w/Yoke Kit (changing this to 1350)
-Heavy Duty RCV Performance USA-Grade 4340 Chromoly JK 35 Spline Inner & 32 Spline Outer Ultimate CV Axle Shaft Assemblies w/RCV's Lifetime Warranty – Included
-Customer to Reuse Stock JK D44 Wheel Ends (Knuckles, Hub Bearings, Disc Brakes)
-*NOTE: Dynatrac Cannot Guarantee Fitment of the Pro Rock 60 Center Section with the Stock JK Tie Rod Assembly (Possible Clearance Issue) **this is where my local fab shop will engineer a custom chromoly tie rod**
 
Just get new rims...spending big $ and compromising the axle for the sake of the rims isn't the best way to go.
 
2007 JKU said:
Just get new rims...spending big $ and compromising the axle for the sake of the rims isn't the best way to go.
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I don't think he's compromising. And he's saving big $ too. It sounds like a $3000 savings over a full 60 axle, then spend another $2,000 on new wheels on top of that? If he's not going over 37's then, seems like a good compromise. 60 gears with a 44 axle.
 
Teraflex CRD60 can still use the 5x5 wheel but give you 35 spline inner and outer shafts with RCV 60 sized joints. I had the currie hybrid as you mentioned with RCVs and quickly found that the axles aren't strong enough. I was having the same desire of not changing or redriling my ATX wheels. There is now a pile of Teraflex parts awaiting install. Currently I have currie, Teraflex, and dynatrac parts sitting on the floor and have to say I am quite impressed with the value and quality of the CRD60 stuff. Much less money than the dynatrac and quality is great. Pm me your email if you want more info as to what I like or dislike and why.
 
Sorry guys, I didn't think there would be much overall interest in my experience so I was thinking that I was saving clutter in this thread. That and I was replying from my ipad which I hate trying to type on! So, I'll tell you my experience and opinions formed based on that experience.

First of all, I want to say that I always feel that there is no such thing as "perfect" or "best". What is best for each user/vehicle depends on the usage, location, other mods, etc, etc. My current fleet has an 08 JK 2 door on 40's among a few other toys. I'm working on a 2013 two door for a friend as well, so there are quite a few parts piled up right now. My truck currently has Rock Jock's front and rear. The front is the hybrid with the stock 44 outer steering knuckles, hubs, etc. I purchased this used, sight unseen, not realizing it had the 44 outers. The scenario with this configuration is that you have the strength of the Dana 60 center with 35 spline shafts, but the RCV's are still a Dana 44 size with 30 spline inner. So the shaft from differential to RCV tapers down from 35 spline to 30 spline. The ball joints are still stock size. The unit bearings are stock size. The brakes are stock size. Now keep in mind that I am a North East guy and wheel HARD. I'm not afraid to abuse my stuff at a level that most people aren't willing to subject their equipment to. I have found that I have twisted the tapered shafts and have wrecked the inner cage of the RCV's several times in the past year. I upgraded to the 300M inner shafts, but still continue to wreck the cages. I have been more careful in the past 6 months but I hate having to be concerned about it. I am in the same situation as the OP in that I have a set of ATX Slab's and really don't want to change wheels. I could redrill the bolt pattern but really don't like that idea either. As I have been researching my options for both this truck and the 2013, I talked extensively to Currie, Dynatrac, and Teraflex. I purchased a few sample parts from various sources so I could evaluate the quality of things myself. After much research, we decided on the TeraFlex CRD60's for the 2013. These axles are sitting on my floor now awaiting other parts for this build, so I've had some time to really check them out. One thing to keep in mind, with 37's you really want to consider some upgraded brakes. The true 60 based outers are going to have upgraded brakes on them, so this is an added cost that you will probably want anyway. I personally feel that if you are going to have the weak link of the Dana 44 sized RCV, why not keep a 44 center section? Save that money for other mods, or ante up for the full 60. Or as someone else pointed out, the 60 outers with 44 center section eliminates the weakest points and saves some cost. When I priced out the Dynatrac vs TeraFlex, comparing as close to apples/apples as I could, the TeraFlex came out $4000 less, plus the fact that the wheels didn't need to change. After seeing the quality of the TeraFlex I am very happy. My own RockJock will be receiving TeraFlex Inner C's, Knuckles, etc in the near future. I am not knocking the Dynatrac stuff at all. There are some advantages to their stuff. I like the fact that the Dynatrac uses off the shelf Ram 1500 calipers, pads, and rotors. The TeraFlex is all custom brake parts. The Dynatrac uses a live spindle with replaceable bearings and seals vs the unit bearings of the TeraFlex. Here in the north east, we end up repacking those bearings once a year which is a small amount of labor every year. With the unit bearing you take it off and replace it with another. Only available from TeraFlex, but unit bearings tend to last much longer with no maintenance. The bracketry on the Dynatrac and TeraFlex is similar quality. The RockJock bracketry is not up to the same standard as the others.

Sorry if I got too long winded! Hopefully I gave you some decent info to work with. If you have questions, feel free to fire away and I'll answer to the best of my ability.

Raceplayhavefun
 
Are the RCV'S tapered when you get them with 35 inners and 32 outers. If they are that would be a game changer with this set up.
 
Yes, the Dana 44 sized RCV is only a 30 spline at the "bell". The outer is 32 spline. The inside of the inner shaft is 35 spline, but the real weak point is the size of the bell itself and the fact that you can only get a 30 spline into the bell.
 
Raceplayhavefun said:
Yes, the Dana 44 sized RCV is only a 30 spline at the "bell". The outer is 32 spline. The inside of the inner shaft is 35 spline, but the real weak point is the size of the bell itself and the fact that you can only get a 30 spline into the bell.
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I'm not sure if I am on the same page or not. If he got the 60/40 hybrid could he run a 60 shaft that is not tapered. Or a 60 shaft out to the stub
 
jeffj said:
I'm not sure if I am on the same page or not. If he got the 60/40 hybrid could he run a 60 shaft that is not tapered. Or a 60 shaft out to the stub
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No, because he is using the 44 knuckle, inner c, etc, the joint size is going to be 44. The shaft will have to be 30 spline at the joint end.
 
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