ECO Hubs Who needs 3:07 gears?

[serpico760]

It would be nice if there could be a comparison between a stock truck, the one with the 3.07 gears, and the hub spider gear delete. A variety of terrains and speeds and loads.

 

[Ronmar]

Good to know, I can’t imagine how much it would pull in low range!

Well if Allisons info holds up, we can kind of imagine:

Cat 3116@225HP ~ TC stall should be delivering around 620ft/lb of torque. At that point just before stall, the TC should also be delivering an added 2:1, so ~ 1240# into the planetary gear set, X 6.93 = 8593# out of the gearbox… Divide by 2 for each driveshaft, so 4297# into each diff. X 3.9 = 16,756#, divided by 2 for each axle shaft = 8378# of torque to each wheel. A 395 85 R20 tire is about 46.6” in diameter, or a 1.942’ radius. 8378ft/lb divided by a 1.942‘ lever arm = 4314# of pull force from each tire. Of course gearbox losses will probably knock 10-15% off of the total, but that is still 3667# to each tire… X4 = 14,668 pounds of truck pull force… it would be nearly double this with the 2x hub ratio…

Drag notwithstanding, a slope calculator indicates a 20,000# weight requires 14,627 pounds of force to be pulled up a 47 degree slope…

 

[Ronmar]

It would be nice if there could be a comparison between a stock truck, the one with the 3.07 gears, and the hub spider gear delete. A variety of terrains and speeds and loads.

I am actually contemplating just that… I like numbers

 

[GeneralDisorder]

And those of us with C7's at 370 HP / 930 Ft/lbs..... my back of napkin calculations similar to what Ronmar laid out indicate the additional power will help significantly offset the higher gear ratio. I look forward to posting videos and measuring performance.

 

[Ronmar]

Yea if my piddly little 6.6 delivers that much, the 3126s and C7s should be even more impressive. with yours at 1/3 more peak torque, roughly 1/3 more pull. ~22,000#?

 

[Xengineguy]

Worked in the home shop last evening. Machining the OD of adapter plates, and welding inner and outer plates together .
Finished 48 pieces….
Dropped the plates to CNC, this morning for drill tap..
The heat treat on the hubs are due back today, (over a week at heat treat). They get washed and bead blasted Then the hubs go to EDM.
Moving along and getting closer…

 

[Xengineguy]

Got the hubs back from heat treat today, look great! Bead blasted and off to EDM tomorrow morning!

 

[Xengineguy]

First hub done at edm today. Needed to tighten it up a little. The fit was better than stock, but not as good as it could be..
Small change in program should be good!

 

[Xengineguy]

This morning I finished pricing on the hub sets. 2285.00 for two axles. This will include. 4 adapter plates, 4 hubs,
4 aluminium caps, 16 half plugs, 4 machined split collars, 16 ss cap screws, 48-3/8” grade 8 flange bolts, 48-m10
flange bolts.
Plus shipping and tax if applicable. Three axles will be 3300.00 And include all parts for three. Plus ship and tax.

 

[GeneralDisorder]

Installed!

Ok so as expected these hubs are total game changers. With my C7 uprated to 370/931 I honesty don't notice a significant difference in acceleration but the whole experience is smoother without the reduction hubs. If anything I think it's faster off the line but I haven't corrected the speedo yet so I need to do some side by side comparison. Will do that soon.

Went straight out to some logging roads (in the dark and pouring rain) last night and found some muddy rutted up roads - off road performance is basically the same from what I can tell.

On the way back home I hit 80 MPH on the freeway. Truck was rock solid even on the wet pavement.

Honestly can't see myself going back. Going to do a 200 mile freeway round trip today at 55 MPH. Will report back.

 

[Ovrlnd1]

As anyone is installing and testing these, it would be great to have a video or pics of the process as well as testing the difference between original and new.
I am excited to see how these go together, perform and the reliability.

 

[Third From Texas]

Agreed.

I'd love some detail on the 30 minute install. I mean is it "Step 1; Use your 50 ton material handling crane and remove engine" or "remove wheel, turn four bolts, replace wheel"?

I admittedly have never broken down one of these hubs but I sorta get the gist. I'm VERY good at taking things apart, though. That's how I got 50 projects running at once.

 

[Ronmar]

I am setting up to do some before and after 0-60 accelerations and hillclimb/start tests. Unfortunately I have to put my cab suspension back together, and I want to get a tach working first before I begin. I expect it to accelerate atleast the same, and I expect I will run out of traction before I run out of torque, as I can only add so much weight to my cab and chassis(about a ton), for testing…

 

[Xengineguy]

As anyone is installing and testing these, it would be great to have a video or pics of the process as well as testing the difference between original and new.
I am excited to see how these go together, perform and the reliability.

One of the gentleman I sold a hub set to is going to do an install video. Very soon. He will probably do the UTube thing. He already has a channel and makes quite a few fmtv videos! Stay tuned!

 

[GeneralDisorder]

The whole drivetrain, especially the engine, really feels like it's a lot happier not screaming at redline. My radiator fan kicked on once last night and it was much quieter and ran for less than a minute before cycling off. After doing 80 mph on the freeway the hubs were still cold to the touch.

Besides air conditioning, I think this might be the best modification I've done to my truck. It's like driving a different (normal) truck now. All the drivetrain parts are spinning at half speed which will prolong their life and with the steep driveline angles - u-joint, etc..... For reliability and longevity I think this is likely one of the best mods you could ask for.

I might do some driving videos and some side-by-side comparisons with other LMTV's. Install is straightforward - I didn't even realize the Xengineguy had posted instructions on his sales thread and I had no issues at all figuring it out from the boxes of parts and hardware.

One change I would make to the design would be a drain/fill hole in the drive plate - it could be as easy as drilling and tapping the hole to re-use the plug from the reduction drive cover. As it is the only way I could figure to get gear oil into the hubs was to leave out one of the hub to drive plate bolts during assembly and fill though the tiny threaded hole.

I used Permatex The Right Stuff sealant (in the cheez whiz aerosol can) and filled my hubs immediately (no cure time). As a professional mechanic I have found this to be totally fine and my hubs are completely dry today. If you use the right sealant and apply it correctly there is no need for any curing time.

 

[Integrusllc]

One of the gentleman I sold a hub set to is going to do an install video. Very soon. He will probably do the UTube thing. He already has a channel and makes quite a few fmtv videos! Stay tuned!

Xengineguy, I apologize for jumping in on the thread. I’m new to the forum and it won’t let me message you directly. Could you reach out to me? I’m wanting to buy a set.
Thank you devin

 

[RRaulston]

What are the odds your MPGs increase??? I'm not a mathematician, but if I get 5mpg and got +1mpg after installing these hubs, that's a 20% increase? dang,.... Can't wait to see a video....

 

[RRaulston]

Installed!

Ok so as expected these hubs are total game changers. With my C7 uprated to 370/931 I honesty don't notice a significant difference in acceleration but the whole experience is smoother without the reduction hubs. If anything I think it's faster off the line but I haven't corrected the speedo yet so I need to do some side by side comparison. Will do that soon.

Went straight out to some logging roads (in the dark and pouring rain) last night and found some muddy rutted up roads - off road performance is basically the same from what I can tell.

On the way back home I hit 80 MPH on the freeway. Truck was rock solid even on the wet pavement.

Honestly can't see myself going back. Going to do a 200 mile freeway round trip today at 55 MPH. Will report back.

View attachment 895739

View attachment 895741

on your first photo.. That collar clamps on to prevent the wheel bearing nut from backing off?

 

[Ronmar]

The whole drivetrain, especially the engine, really feels like it's a lot happier not screaming at redline. My radiator fan kicked on once last night and it was much quieter and ran for less than a minute before cycling off. After doing 80 mph on the freeway the hubs were still cold to the touch.

One change I would make to the design would be a drain/fill hole in the drive plate - it could be as easy as drilling and tapping the hole to re-use the plug from the reduction drive cover. As it is the only way I could figure to get gear oil into the hubs was to leave out one of the hub to drive plate bolts during assembly and fill though the tiny threaded hole.

How was the 2-3 shift? I have a theory that our 2-3 will be nicer with this configuration due to the way the Allison brings on the lockup clutch in 3rd.

Yea the fill is thru a inner to outer hub mount hole. The amount of oil in the rear is not so critical, any extra you add will just flow back into the main axle housing, with a proper fill of the axle the rear hub heights are maintained automatically

The original instructions say add 11-13 oz of oil from empty, but that was for a different size housing full of the hub gear set. I believe that volume of oil was to set the oil at a particular height in the housing. The other method for filling and checking front oil level is to roll the housing drain plug to 4 o'clock and add oil till it runs out. The O’clock method in the original configuration sets the oil level(bottom of drainplug opening) to just above the bottom of the axle shaft. How much oil it takes to reach the same level in the new configuration I have not yet determined.

The bottom edge of the rear axle fill hole on the pumpkin sets the oil level just below the center of the axle. Differential oil level is considered normal if within 1” of the bottom edge of the filler hole, to the bottom edge when cold. That is between bottom and middle of axle shaft . I would say between these two heights would be acceptable in the front to keep the axle bushing and outer hub bearing properly lubricated And allow room for any expanshion.

With this setup there should only be heat from the bearings, and that should be pretty low…

 

[GeneralDisorder]

I am on a 112 mile round trip (at the halfway point now eating lunch) with my friends 2003 M1078 A1 following right now. We both filled out tanks at the same pump to the same level and will do so again at the end of the test. His truck is screaming to keep up with me at 56-57 mph and cycling the radiator fan every 5-7 minutes. My truck hasn't kicked on the radiator fan even once today. The cab is quiet, on small freeway grades it has kicked down to 5th gear a few times and then goes right back to 6th. Speed is set with cruise control and the CAT ECM is in control on throttle.


All the shifts are very smooth. The 2-3 shift is noticably softer, and all the downshifts are also very gentle.