Locked hubs and part time 4 wheel drive question

[matt s]

Ok this falls in the "stupid question" or "I really should know the answer to this" area.

I have manual hubs on my blazer and 205 transfer case. Once the hubs are locked (obviously stopped to do this) can I then switch in and out of 4 wheel drive on the transfer case while moving? If so at what speeds? From what I have read and thought I knew you can, as the axles and differential are already spun up to speed due to the locked hubs.

I just don't want to learn I was wrong the hard way. My previous rigs were all auto hubs with shift on the fly capability.

 

[BKCowGod]

You can switch in and out, and even drive extended periods in 2wd. I don't do it because in theory it does wear stuff. But if I'm up in a snowy area or going to FS roads and the like I will switch in at the beginning and avoid the constant getting out and getting in part of shifting.

Also - shifting the transfer case should never be done at more than about 10mph. What works well for me: Go forward at 5mph, drop into neutral, shift, drop back into drive. I pretty much never crunch my transfer case.

 

[Cody1771]

when switching from 2H to 4H its actually better to switch while at low speeds. this is because at stoped, while the gears are not turning, you still have to somewhat force the gears to mesh exactly. the synchronizers cant do there job, while moving the gears are spinning at exactly the same speed and your synchronizers will sync up the gears on the shift. but you have to stop to switch into 4L, and generally give it a bit of a kick in reverse to fully engage it. just remember while shifting not to stop in nuetral go right from 2H to 4H

 

[matt s]

Thanks, that's what I thought. I was pretty sure you had to be going slow to do it. I had read around recently and was getting the impression that it could be done at much greater speeds, not something I had though was possible. I did drive an early 80's suburban with locking hubs for a while and would drop out of 4H at speed but never engaged it, thinking (it appears correctly) that you had to be going pretty slow to do it.

 

[dbreid]

I used to have the same issue with my 205. It was hard (physcially) to shift, and I found myself rocking the truck, or slowly crawling forward to shift it. Lame. So I installed a Twin stick, and modified the shift rails for the case, and now it is one finger shifting at a standstill, or rolling. The linkages just suck on the 205, and the twin stick splits them, and replaces worn out connections with heims.

Plus, you get FWD low and FWD Hi.

 

[BKCowGod]

Thanks, that's what I thought. I was pretty sure you had to be going slow to do it. I had read around recently and was getting the impression that it could be done at much greater speeds, not something I had though was possible. I did drive an early 80's suburban with locking hubs for a while and would drop out of 4H at speed but never engaged it, thinking (it appears correctly) that you had to be going pretty slow to do it.

It can be done at very high speed. But generally only once per transfer case :smiley_drive:

 

[redthies]

Actually, as long as you back off the throttle to "unload" the drivetrain, you can safely shift in and out from 2hi to 4hi at speeds up to 50mph. If your particular 205 doesn't like to do this smoothly, then stick to the lower speeds. I have had no issues with numerous 205s in both ford and gm trucks while shifting at 50 in snowy conditions. (I can't think of any other time you would need 4wd at higher speeds.)

 

[T.Low]

Matt, any links to threads about how that Balzer is doing for you?

 

[DiploStrat]

Convention Wisdom

Remember, if you have locking hubs, GM recommends that you drive at least ten miles a month with the hubs locked to assure that lube in the front diff gets spun around.

Also worth remembering - the Dana 44 axle has THREE bearings; two for the front wheels and a smaller, inner bearing that carries the drive shaft. That third bearing is smaller and dries out faster than the wheel bearings, especially if you drive in water. (By 1977, GM called for the three bearings to be repacked every 12,000 miles.) You don't want to let that third bearing dry out. Ask me how I know! Hint: It is no fun to drive the Sahel in 4x2.)

(Great photography BTW!)

 

[Lichen]

Remember, if you have locking hubs, GM recommends that you drive at least ten miles a month with the hubs locked to assure that lube in the front diff gets spun around.

Also worth remembering - the Dana 44 axle has THREE bearings; two for the front wheels and a smaller, inner bearing that carries the drive shaft. That third bearing is smaller and dries out faster than the wheel bearings, especially if you drive in water. (By 1977, GM called for the three bearings to be repacked every 12,000 miles.) You don't want to let that third bearing dry out. Ask me how I know! Hint: It is no fun to drive the Sahel in 4x2.)

(Great photography BTW!)

This picture needs some explanation. When was it taken? The man seems to be wearing a 1970's bell-bottom leisure suit. Got enough spare tires? Why is he shoveling in the middle of the road?

 

[matt s]

Actually, as long as you back off the throttle to "unload" the drivetrain, you can safely shift in and out from 2hi to 4hi at speeds up to 50mph. If your particular 205 doesn't like to do this smoothly, then stick to the lower speeds. I have had no issues with numerous 205s in both ford and gm trucks while shifting at 50 in snowy conditions. (I can't think of any other time you would need 4wd at higher speeds.)

Interesting, and it makes sense. Anyone want to back up this claim? You are correct I am thinking about this winter and snow. Pulling over is not always a great option, slowing to a reasonable speed and shifting would be nice.

Matt, any links to threads about how that Balzer is doing for you?

I should start a thread detailing the journey. Basically I love it, however I am still unraveling all the previous owner/years of wear and in some cases poorly done mods and repairs. I found a broken off bolt in the head, it was covered up and put back together. Who does that!?? That is just one example of many, but hey it's nearly 40 years old it goes with the territory.

It's costing my pocket book, but I am getting very near to a set up I can live with for some time. Overall cost so far is still pretty reasonable all things considered. At least I can do most of the work myself. Long term there will always be projects, I am currently just trying to keep on top of the mechanical stuff so I can start to play with the camping build out fun stuff.

Remember, if you have locking hubs, GM recommends that you drive at least ten miles a month with the hubs locked to assure that lube in the front diff gets spun around.

Also worth remembering - the Dana 44 axle has THREE bearings; two for the front wheels and a smaller, inner bearing that carries the drive shaft. That third bearing is smaller and dries out faster than the wheel bearings, especially if you drive in water. (By 1977, GM called for the three bearings to be repacked every 12,000 miles.) You don't want to let that third bearing dry out. Ask me how I know! Hint: It is no fun to drive the Sahel in 4x2.)

(Great photography BTW!)

Good information, I will be checking on that bearing. Good looking rig in that photo, I always liked that color. I think I will lock the axles for tomorrows drive to work. That should cover this month, and by the end of next we will have snow, so.....

Thanks for the compliment on the photos too!

 

[Larry]

Here is a hint to help make the 205 shift easier. Grease the pivot bolt! Many 205’s that I have seen and owned ( ’72 K5 Blazer w/auto trans, ’78 K20 w/manual trans and ’78 K10 w/manual trans) have a zerk fitting in the head of the shift lever pivot bolt but I have also seen some without the zerk fitting. I suspect a greaseable bolt can be obtain through 205 specialists like National Drivetrain if you need one. Grease that baby up while doing routine maintenance and it will shift silky smooth like a new truck with a manual shifter.

As far as shifting, I shift my manual trans 205 combo between 2HI and 4HI at any speed by just letting off the throttle and moving the lever. Of course, this truck doesn’t see speeds higher than 70 MPH either. :smiley_drive:

I often toss it into 4LO without coming to a complete stop as well and it accepts the shift just fine without grinding. This actually happens by accident often on the trail when doing a lot of shifting in and out of 4LO.

 

[matt s]

Wow that fast! I guess I am going to have to see how it goes. Mine is stiff, so I think I will see about greasing it up like you mentioned.

 

[78Bronco]

I would say you can shift between 2H and 4H up to 40mph. As long as the hubs are locked and front&rear tires are travelling at the same speed it will all work. I've done this with an 1996 & 2004 F150's during the winter on snow covered highways.

Mitsubishi says I can shift from 2H to 4H at up to 60mph if tires are going same speed.

 

[luangwablondes]

DiploStrat
Do I ever have fond memories of shoveling sand, especially in October and November in Botswana. That's why I made the switch to shorties and diesel engines. My shovel never got used for that purpose again.