Diff lock side effects

[cranetruck]

I have no experience with locking differentials and am curious about possible side effects when not used.

If a deuce was equipped with these (Norweigan M621), would that decrease mpg, cause problems when taking turns etc?

TIA for any info on this.

 

[ojsdna744]

I might be able to help...but I'll need to know a bit about the locker. Does it lock by itself? Or do you 'lock' the differentials when needed?

 

[cranetruck]

No specific locker in mind, "side effects" from any and all available.
(meant to say decrease mpg, not increase)

 

[ida34]

Greater tire wear. It would make turning more difficult. Don't know if it would be noticeable in a deuce. Tire noise when turning. If in the rear the rear would tend to go sideways easier on ice and snow because when the traction is lost it is lost for both wheels. Stronger lockers give stronger issues. Weaker ones have most of the same issues but they are not as pronounced. I would say mpg would go down slightly because of greater tire friction. It may be so small as to not be noticable.

 

[BFR]

I agree w/ Chuck if you are talking about auto lockers (i.e. detroit), but if it is a selectable locker (you manually choose when to lock) the diff will feel/operate just like an open diff when unlocked. A while ago there was talk of ARB making a locker(selectable) for the 2.5 ton axles, but I don't know what came of it.

 

[ida34]

Now they are making electric lockers. Both the air and electric actuated would give you the best of both worlds with little or now side effects.

 

[Recovry4x4]

Bjorn, if you were to abscond with an M621 axle, you would notice nothing. No decrease in mileage or any side effects other than when you flip the switch, both axle will be turning. Trying to turn with it locked will cause some grief and leave a far amount of rubber on the ground. This would be the same for any selectable locking differential. With a Detroit you will notice noises when cornering. If you corner under power it will probably not unlock depending on how much power is applied. Once you get to know the quirks of the Detroit, you really won't notice much outside the noise. Sometimes you just need to let off for a brief second when powering through a turn so that it will unlock. You shouldn't see any decreas in mileage once you get used to its feel and prevent it from locking unwantedly. It will differentiate just not under power. It will get you going with only one drive axle though. I see what you're thinking!
Here's a pic of the M621 axle and a shot if the inside.

 

[Jones]

BE ADVISED! An amusing little quirk we've found in vehicles having front axles equipped with locking differentials in hilly terrain; the downhill wheel, because of the weight shifted onto it, will be the one which gets power and traction. This can and does cause the vehicle to rotate and point/pull itself downhill. This is only desirable if you were planning on going that way anyway; otherwise you can easily end up losing the vehicle and occupants on an uncontrolled descent. This is mildly annoying to motor pool personnel who have to go retrieve whatever is left of the jeep or HMMWV or CUCV. It's even more spectacular with something as big as a deuce or 5 tonner since they won't even be slowed down by fairly good sized trees or boulders. See also; "to plummet".

 

[cranetruck]

Thanks for the answers!

Yeah, one drive axle definetly leaves something to be desired.

Note: My son got an upgraded rear axle for his CJ-7 and I noticed that the axles were almost the same diameter as the ones on the deuce. Didn't measure it, but couldn't be off more than 1/8 inch. Makes one wonder how easy the deuce axles could break under added load, with a locked differential on a side slope for example.
Kenny, are the axles on the M621 axles the same dia as the regular M35's?

 

[Recovry4x4]

Bjorn, the M621 axle is a direct bolt in for our trucks.The deuce axle is 1.62 dia. Depending on what Adrain got it might be close. The semi floating Dana 60 axles are 1.5 dia. Interestingly enough, the V100 commando has the same axles as a deuce but has a Detroit Locker. They have a larger dia axle and axle breakage was a problem. Don't have details as to wether it was with deuce axles and they upgraded or if they break the larger axles. For the extreme dude, Ouverson has 2" shafts, a locker similar to the detroit in 2" and I'm sure can make you a 2" locking hub.

 

[rizzo]

Thanks for the answers!

Yeah, one drive axle definetly leaves something to be desired.

Note: My son got an upgraded rear axle for his CJ-7 and I noticed that the axles were almost the same diameter as the ones on the deuce. Didn't measure it, but couldn't be off more than 1/8 inch. Makes one wonder how easy the deuce axles could break under added load, with a locked differential on a side slope for example.
Kenny, are the axles on the M621 axles the same dia as the regular M35's?

did your son get a dana 60 1 ton axle? they are just a little smaller than the rockwell.

 

[Trango]

Rockwell axles are 1.62" at the splines with a neckdown in between. A chevy 14 bolt is 1.5" at splines with a neckdown.... The strength in the rockwells really comes into play in the front axle, with its HUGE ujoints.

 

[cranetruck]

Adrian got one-piece axles for his AMC 20 rear axle. They are made by Superior and are about 1-3/8 necked down to about 1-1/4. Not as fat as the deuce's after all.