The GMC CCKW

Wanted to check with everyone on this topic. I've seen lock-out hubs for M-35's; will they work on the CCKW's? Vehicles of Victory have milled out front hubs for sale. What do you guys do? LOH vs. Free wheeling hub? Or do most of you leave everything as stock? Thanks for any input. Hammerhead

Hammerhead, I know we're divided by a common language, but I don’t understand your question. In one post you state you want to keep your truck as original as possible, mirrors accepted, and then ask about modifying the front hubs?

When the truck police read that, boy will you be in trouble.

As I'm calling from far away Europe, and therefore fairly safe from arrest, my experience of Neutered Hubs is that they eased the steering effort, but did little for economy. They were however a bl**dy nuisance when off-road and a little 6 x 6 traction action was needed. But then not everybody wants to leave the paveway.

Waste of time and money. If you could find locking hubs, you will never save enough fuel to recoup your investment. Your moving axle parts are quite durable and will not suffer any wear. Milled out hubs still have friction. If you have it registered as an historic vehicle, you will not drive it enough miles to wear it out, as use is limited.

I have taken the splines out of the hubs and keep another original set under the seat. I do this for fuel economy. My CCKW will get up to 8 gpm vs 6 with splined hubs. I have a lube fitting in the hub so as to grease the non-splined area.

Lee

A number of us have dummey hubs that are just caps and we keep a real set under the seat in case they are needed.

I notice a great difference in noise over the road and less mainentance to the front end. I can actually hear the difference Gas mileage, I have never checked. I usually get 6.5 to 7.5 mpg towing trailers most of the time and there are a lot of hills around here

Only the propeller shaft, transfer output shaft bearing, differential, axle safts are involved. In rear wheel dribe there is no laod on these components, wear is negligible, the difference in rolling resistance is nil due to mas of the vehicle.
Does not make real difference, steering is really not affected as the CV joints still have to pivot. The guys who do the mod want to believe it it is big difference, the professionals look at it differently.

Not much proof of the Army ever going big for them on tactical vehicles, they surplused all the Clary Flanges used on MB/GPW/M-38, along with those for the WCs and M-37.
No evidence of any G-508 or larger WWII/Korean era 6X6 using them.
Warn and Dual Matic got rich on them in the Civilian Market.
They do not stop wear where it really counts, and that is the steering components along with trunnion bearings in the Knuckles.
Again it is the opinion of those who want to believe in them, or that of powertrain specialists who service them.

The steering knuckles still need to be serviced on schedule, free wheeling has no bearing on this. (Pun)

I do appreciate all the input. I've always leaned toward leaving everything as original as possible except in areas of safety or protecting these historic military vehicles. I've been a member of the MVPA since 1988 and periodically the question of LOH and/or milled front hubs comes up. I wasn't interested in more speed just decreasing wear/tear if the modification did help.
Hey Capt. Karoshi; hopefully the truck police won't come for me!
dr deuce; you're my idol....50,000 miles in a deuce! In all seriousness I do hope to drive my CCKW alot more this coming spring and summer. It's been 4 years since it's restoration and I've only driven it 250-300 miles.
Joel....I am a firm believer in PM by the TM!!
Thanks, Hammerhead

If you drive 250 miles a year, then you don't need them. If you drive 2,000 miles a year then you will find that they will save on maintenance, time and $$. You can actually hear the difference!

Everyone I know who has installed them has not regretted doing so and has observed a difference. It costs about $125 to make a set of dummy caps.

Logically, when you think of all that gear oil in the diff and all that grease in the knuckle that you are not churning, it has to make a difference in mileage.

Remember, maintenance wise, the givmint had unlimited $$, time, parts amd people to maintain these trucks. Do you?

And think of the two outer axle seals of the Banjo Axles that have a dead axle distorting them , as there is no longer any support at the outer axle end to keep it centered. 90 gear oil on brake shoes and diluted lower trunnion bearing grease is greater possibility.

Actually the opposite is true! Less maintenance of the knuckle seals. Fewer replacements of any of the seals. THAT is why I started doing it!. Maintenance is reduced about 1,000% by deadening the front end!
With driving as many miles as I do (~2,000-3,000 miles per year) it was getting expensive and time consuming to do a lot of maintenance on the front ends and with the number of CCKWs and Chevys that I have and plans to restore, maintenance issues that don't have to be, in my case are eliminated. The number of times that I use the front WD is extreemly limited. I used the Bomb truck FWD once this year for the first time in about four years. That is four years, or about four thousand miles ( I do not drive that as much as the cargo CCKW) of wear and lowered gas mileage at $2-3 per gallon that I don't need thank you very much

I have 1,000's of miles on both the CCKW cargo and the Chevy Bomb truck with these hubs and would never go back to full time hubs.
Others who have used the dummy hubs have had similar experiences and would not want to go back either.

I don't have unlimited funds, parts, or time, so finding what works in a non-combat situation is what I do. After all, my cargo CCKW now has over 80,000 miles on it!

Everyone has to assess their own needs and judgement. After all, we don't change our cars oil every 1,000 miles anymore either

Has anyone removed rear axleshafts and/or driveshafts, for longer trips, to improve mileage? What result?

CCKWs have a history of the rapid demise of the remaining differential when this is done.

>Has anyone removed rear axleshafts and/or driveshafts, for longer trips, to improve mileage? What result?>


Yup! You will get stuck on paved surfaces that twist the truck slightly
Been there, tried that. Put a matched set of tires on the rear and neuter the front as described herein. Has worked great for me and others for 1000's of miles

I bought this set new in 1985. They are AVM's from Brazil - no longer made. They were a little over $300 back then. They have been great and woth every penny IMO. Cold 90 wt gear oil really eats up power at highway speeds.

They do stick out some but not as far as the duals do. I also had a set of Duomatics on my M6 Bomb truck and really liked them too.


Shot at 2004-12-27

Here is a slightly better picture of them.

During my CCKW makeover to stop leaks, I pulled the shafts from the intermediate rear axle and found they had been cut. So my truck didn't have axle shafts for the 1st two years I used it. Well, now it has both axle assemblies rebuilt and I got the new axle shafts I needed. I haven't noticed any mileage savings at all and I monitor is very close.

Well to be fair that intermediate ring and pinion and drive shaft was turning all the time even with the axle shaft cut. Lock out hubs stop all the front axle ring and pinion and driveshaft motion. It isn't going to save much fuel for an ocasional use vehicle and I would agree that it is not nessasary.

I have used my truck on the highway for most of it's milage and I feel anything extra helps for highway use.

"The guys who do the mod want to believe it it is big difference, the professionals look at it differently."

What is a professional? Can I be one? Pretty please.
Barry