Lockouts

If I installed a set of lockouts on my CJ3A, do you think that would gain me any topend speed? I don't mean 20 mph or anything, I mean instead of 45 mph, you might get 50, or won't it make any difference? Thanks in advance.

 

You should in stock form be able to make it to 55 mph with 5.38 gears. With 30" tall tires the jeep should make it to this speed at 3400rpm.
If your jeep will not make it to this speed then there are tuning problems somewhere. You might want to start checking timing, plugs, carb and other such things.

 

I totally agree that they will save a little fuel but I am not sure there is any substantial overall net gain on stock early models due to period design issues with the spicer 18 t-case and closed knuckle front axle, I feel there is more advantage in using them on intermediate and modified rigs. I will explain, But this is only my opinion for your consideration.

The model 18 t-case has three bearings and a bushing on the output shafts, the front output shaft is supported by a ball bearing at the yoke and a bushing where it mates up with the rear shaft that is supported by two tapered roller bearings.

This bushing is only intended by design to maintain alignment of the shafts so the output clutch gear can easily mesh with the output clutch shaft when shifting from 2 to 4 wheel drive, If modified so the front axle is allowed to freewheel the bushing will have to serve as a bearing much like the input shaft of a transmission that is supported by needle bearings.
I dont think the model 18 was ever intended to be used this way. Later t-cases like the model 20 completely separate the whole intermediate shaft issue and therefore do not turn at all in 2 wheel drive with the front end freewheeled.

The other design issue to consider is that the closed knucle front end depends on lubricant being thrown out radially inside the knuckle to keep the top knuckle bearing and knockle seals lubricated, Probably where the old rule of locking your front end in once a month for 5 miles to keep things lubricated may have started besides keeping lube on everything to prevent rust from condensation.

Locking hubs are great for many applications but for a stock early rig driven within design intent the money may be better spent on high quality lubricant as any real net gain overall will likely be marginal.

 

i notice a big difference in acceleration when iv got mine unlocked. top speed is probrobly affected a bit too but not that much a few mph

 

I was just curious. I don't know how fast mine will run, I haven't had it on the road yet. I had allways heard that 45 mph is cruising speed with these pups. I grewup with a 3a back in the mountains of W,Va, but we never took it off of our mountain farm. Here in Ohio, I don't have those old dirt roads to lumber on, it's black top around here. I would be happy to get between 45-55 mph out of it to keep from getting run over he he!! Thanks for the replies guy's!!

 

Let me put this into proper perspective. Bushings like what are in the spicer 18 transfercase are a product of the 1920-1940's engineering.
My lathe was designed in the 1930's and built in 1943, this machine was manufatured unchanged until 1979 in the US and longer in its overseas models.
There is not a single bearing anywhere in it, that means no taper, ball, roller or any kind of modern bearing known. The machine is totally based on what in those days were known as plain bearings, in other words bushings or hard steel riding on an iron surface with a oil wicking system on it. My machine has survived for 65 years this way running under load at anywhere from 50-1150rpm all while running on 10wt oil.

The bushing in your transfercase were designed to run that way its just that old of a design. Heck, main, rod and cam bearings in a modern engine are basically a bushing.

 

The thought of that bushing in the transfer case has crossed my mind too. That said, I have a friend who has a 1949 pick up with a Chevy V8 and Borg Warner overdrive that he has driven for at least 45 years. In the 60's he even used it to flat tow drag race cars. It had Warn hubs on the front, model 18 etc. He sometimes drove it 70 mph+ towing those old race cars and never had a problem with that bushing. I was a kid at that time and even knowing that he had installed a later model power brake unit / master cylinder, it still had the original brake shoes / system. Don't know how he would have stopped that thing at 70 mph towing a car. He still has the truck and it is still running. He has rebuilt the transmission and transfer case over the years, with the bearings in the intermediate gear being the problem with the transfer case. I think the bushing in question is beneath the oil level at all times isn't it? As far as the front axle, the upper king pin bearing lubrication may be another good argument. I think locking the hubs periodically just to slosh lubricant around it probably a good practice. I have had 3 CJ2A's and 1 CJ3A in my lifetime all with locking hubs and never had an issue. Only one had locking hubs on it when I bought it. ALL had the upper bearing worn out when I got them. My friend bought a 55 CJ5, with no hubs and the upper bearings were worn out. As far a speed, I think the huge flat windscreen gets you on top end whether with hubs or not. I never checked mileage one way versus the other.

 

With regard to my comment about the bushing and response by Patrick & Mcruff, To both thanks, I know that we have been running locking hubs on these for a long time with apparently not many issues and Mcruff is absolutely correct in that plain bearings work well in many applications when properly lubricated.

I was basing my comment on observation of function and the assumption that when the model 18 was developed they may not have planned on freewheeling the front end. When I put new bearings in my unit I observed signs of excessive heat and mild scoring on the old bushing and pilot end of the short output shaft, Gear lube from this specific area also smelled very cooked and there was some thick sludge ( like putty ) in the back of the bushing bore plugging the hole in the shaft to let lubricant circulate.

The condition I found in my unit is probably due more to past neglect of fluid levels & changes rather than the bushing not being able to handle the load regardless of original design intent ( no doubt lost to history )

After reading Mcruffs comments and rethinking the issue my initial conclusion may have been premature.

Thanks

 

knuckle pudding is.....knuckle pudding.
if you pack the king pin bearings as you do a wheel bearing, lubrication never will be a problem IMO.
knuckle pudding is more for the axle ujoints...if they are not turning, no lube is needed.
all of the above is my humble opinion

 

but oldschool Warns on the front of any early tin just looks so much cooler than flanges...

 

I am likely to stubborn for my own good sometimes I totally agree that Packing the knuckle bearings, knuckle pudding and locking hubs work with no apparent side effects on the model 18 t-case.

For the way I drive flanges and 140wt work well for me, As always its great to share opinions with fellow jeepers as there is always someting to learn or a fresh perspective.

 

x2

I don't feel a sensitive improvement in accel. or top speed. At my appreciation, the advantage is that with them disconnected and 2wd, the axle shafts, ring&pinion and driveshaft don't work and do not get worn out.