When to lock front hubs

[Pawnshop]

LOL
same here I was glad I had a can of de-icer in the glove box.

I used the open end of a BAW (Big A** Wrench)

 

[OL AG '89]

My "Rule of Thumb" is if I think I'm gonna need 4 wheel drive. I lock em in!!
If I end up not needing them, it's just a bonus!! It's not a daily driver so no worry about on-road issues.
When I lock them in I usually do a "once around" the vehicle, with one of the sons driving while I check the operation..... ASK me WHY I now do this!!!!

 

[Barrman]

That is funny Sam.
Now, the issue that seems to be hot in this thread about references to the technical manuals. The original poster of this thread has been here at least 5 months. Had several threads over that time about his electrical, charging and I thing starting system. I know the -20 trouble shooting section was brought up many times in those other threads. Specifacally appendix F. I also know that was before the TM section of this web site went down. When the TM section went down, another member put them up on his web site. Several people have a link to the manuals on Jatonka's site in their signature line even.

So, with the fact that he has been referred to the TM's in the past, had access to them and has access to them. I naturally figured he probably printed out or bought a complete set. I know several other members have in their signature line a listing of all the TM's that apply to the CUCV with the suggestion that anybody owning one should buy or print them. That is why I referred him to the -10. That is the manual that has the information about how to shift into and out of the different tcase gears.

So, with me coming along 2 hours after he asked the question and got an answer already to his exact question. I wrote where he could find every detail about his question in case he wanted to look it up more or just become more familiar with the truck. Including the warning in bold print about every other line "Do not engage 4x4 unless the front hubs are locked" or something real similar.

Sorry to offend, but most of us that say read the TM don't say it unless it is part of the answer, the answer has already been given or somebody is so lost no amount of posting will straighten them out unless they spend days reading the TM while sitting in the truck.

 

[Iamnewatthis]

That is funny Sam.
Now, the issue that seems to be hot in this thread about references to the technical manuals. The original poster of this thread has been here at least 5 months. Had several threads over that time about his electrical, charging and I thing starting system. I know the -20 trouble shooting section was brought up many times in those other threads. Specifacally appendix F. I also know that was before the TM section of this web site went down. When the TM section went down, another member put them up on his web site. Several people have a link to the manuals on Jatonka's site in their signature line even.

So, with the fact that he has been referred to the TM's in the past, had access to them and has access to them. I naturally figured he probably printed out or bought a complete set. I know several other members have in their signature line a listing of all the TM's that apply to the CUCV with the suggestion that anybody owning one should buy or print them. That is why I referred him to the -10. That is the manual that has the information about how to shift into and out of the different tcase gears.

So, with me coming along 2 hours after he asked the question and got an answer already to his exact question. I wrote where he could find every detail about his question in case he wanted to look it up more or just become more familiar with the truck. Including the warning in bold print about every other line "Do not engage 4x4 unless the front hubs are locked" or something real similar.

Sorry to offend, but most of us that say read the TM don't say it unless it is part of the answer, the answer has already been given or somebody is so lost no amount of posting will straighten them out unless they spend days reading the TM while sitting in the truck.

Agreed, and no offense taken.
I think we all have a valid point.
I should be dong more reading for sure.
I should also do allot of stuff more.
But life just wont have it. lol.
Work, kids, dogs, kids in sports, old house falling down around us, etc., etc.,
just not enough money or time to do anything 100% well these days.
I have glossed over the TM's when i had 20 minutes, and i do have the civilian manual as well. I have done allot more work on this thing than i have told anyone.
Just some stuff comes up and I dont have time to sit and read/hunt for it.

Like yesterday, the truck just turned itself off as i was pulling into a parking lot.
I thought it was out of gas so i put in the 4 gallon can i keep in the back. As I was
I noticed i could see that it was almost full. For whatever reason, after cranking for awhile, it started again, i drove to the gas station, it was nearly full, only took 2 gallons. I could see the gas in the filler neck. I drove home, changed the fuel filter. No problems since. We'll see.
The gas gauge is way off, reads almost on empty with a full tank.
Dont know if the gauge has anything to do with anything at all.
I will go thru the trouble shooting manual tonight about 11pm.
Hopefully that will help me figure out why it shut off.

 

[OL AG '89]

Cant resist since we're all chiming in.....

Probably the GAS you put in it
shoulda used premium

refer to it as a FUEL station as others will confuse your efforts.....

 

[K9Vic]

Cant resist since we're all chiming in.....

Probably the GAS you put in it
shoulda used premium

refer to it as a FUEL station as others will confuse your efforts.....

It is fuel, not gas.

 

[stumps]

Just as a word of warning:

When you have your front hubs locked, all that fluid in the differential creates drag, just like you have the brakes on a bit all the time.... which is why you have the hub selectors in the first place.... Well, a differential full of nice cold, stiff oil, and a slick road surface will make your front wheels slip and stop rotating. When that happens, you will have no steering. If you have your hubs locked, you should be in 4WD.

-Chuck

 

[KsM715]

When you lock your hubs, BOTH wheels will be turning at the same speed all the time, until you unlock them. When you are turning, the inside wheel naturally will want to slow down while the outside wheel be...in essence pulling the vehicle in the desired directed. Any time your hubs are locked and are driving on pavement, you will get a shudder or wheel hop because each tire is will be moving at a different speed due to the turn...When that happens, SOMETHING has to give and thats where you get a shudder or wheel hop. While occasional wheel hop is not a BAD thing, I wouldnt go any further on pavement with locked hubs then I had to. Off road isnt that big of a deal, as loose dirt is more forgiving on axle shafts and slpines then asphalt. just my

Hope that helps.

Do CUCV's come with lockers in the front? Im pretty sure unless it has a locker in it the differential will let the inside and outside wheels turn at different speeds. (unless the oil is so cold and thick that it wont allow it, but I bet it would be warm enough after just a few miles of driving with the hubs locked in)

 

[ohfisherman]

driving with locked hubs will decrease fuel economy too...

 

[duffman1993]

Remember something though, un-lock em before you drive on dry pavement. The locked hubs can make the drive shafts fight each other inside the diff. It can cause damage and wear & tear. loose dirt, gravel, snow ice, mud, it's fine. But un-lock em when yer driving on dry pavement.

 

[dskchevy]

I just wait till stuck and have the wife jump out and lock then in.......................

It warms up the inside of truck very fast

 

[kevin-m1008]

Remember something though, un-lock em before you drive on dry pavement. The locked hubs can make the drive shafts fight each other inside the diff. It can cause damage and wear & tear. loose dirt, gravel, snow ice, mud, it's fine. But un-lock em when yer driving on dry pavement.

I have to disagree with this statement. As long as the transfer case is in 2wd. the front and rear drive shafts are NOT connected in the transfer case. So they will NOT fight each other, bind or anything else with the two exceptions being wear of front drive line parts which is very little, and of having worse fuel economy due to the turning of the front axles, drive shaft and R&P. which was one of the original reasons for installing locking hubs.
NOTE: most 4wd vehicles did not even have locking hubs until the 70's but were available aftermarket starting sometime in the 50's with Warn being one of the original manufactures.
I own a M715 with detroit's front and back with the hubs locked in and the transfer case in 2wd you will not notice a difference in drivability. Detroits only lock the axles together under power which if your in 2wd cannot happen regardless of what the hub position s are. I believe the only way you will notice a difference in driveability with your hubs locked in and in 2wd is if you were running a spool up front .

 

[kevin-m1008]

Just as a word of warning:

When you have your front hubs locked, all that fluid in the differential creates drag, just like you have the brakes on a bit all the time.... which is why you have the hub selectors in the first place.... Well, a differential full of nice cold, stiff oil, and a slick road surface will make your front wheels slip and stop rotating. When that happens, you will have no steering. If you have your hubs locked, you should be in 4WD.

-Chuck

This statement is true but mis-leading. Cold gear oil will increase resistance to the turning of your wheels with the hubs locked in. But after living in Minnesota for a few years back in the 90's. where the roads can get the slickest black ice. I have never seen or heard of the front tires not turning in a properly operating front end of any 4wd vehicle with the hubs locked in and in 2wd.
Now is it possible yes but not something that I would even worry about. as when the roads start getting that slick you will have put it in 4wd anyways.

ok I need to go work on my truck now.

 

[stumps]

This statement is true but mis-leading. Cold gear oil will increase resistance to the turning of your wheels with the hubs locked in. But after living in Minnesota for a few years back in the 90's. where the roads can get the slickest black ice. I have never seen or heard of the front tires not turning in a properly operating front end of any 4wd vehicle with the hubs locked in and in 2wd.
Now is it possible yes but not something that I would even worry about. as when the roads start getting that slick you will have put it in 4wd anyways.

ok I need to go work on my truck now.

Believe what you want, but I wrecked my pickup truck just that way.

I needed to travel on about 4 inches of fresh unplowed snow, so I locked the hubs and went on my way. I decided that the truck seemed to have enough traction that I didn't really need to be in 4WD, so I switched the transfer case to 2WD and continued, fat dumb and happy. It took about 60 seconds for the front wheels to stop turning, and for my truck to spin out. I was traveling on a straight road up a slight incline.... I was going slow and steady at the time, about 25MPH. At the time I did this, I had been driving for 20 years, and had plenty of experience driving 2WD pickup trucks in similar amounts of snow.

The warning stands.

-Chuck

 

[KsM715]

Did you have water (turned ice) in that front end? I too have been driving for over 20 years, except for '91-'94 when I was stationed in the UK, I have never lived any farther south than Kansas. This past week the morning lows have been below zero and we have had snow packed roads. My driveway from the house to the street is packed snow, downhill with a curve right out of the parking area, my Jeep has nearly bald mud terrain tires and no locking hubs on the front, the front diff is spinning full time, my front end has never locked up from cold/thick oil. Right now as it sits I can put it in drive and lightly apply the brakes and the fronts will lock and slide as I idle and the rears will continue to push until I lay on the brakes hard enough to stop the rear wheels. Thats how little traction my front have.

I would guess you had some other mechanicle problem with your front end to cause you to lose control.

 

[DokWatson]

Just as a word of warning:

When you have your front hubs locked, all that fluid in the differential creates drag, just like you have the brakes on a bit all the time.... which is why you have the hub selectors in the first place.... Well, a differential full of nice cold, stiff oil, and a slick road surface will make your front wheels slip and stop rotating. When that happens, you will have no steering. If you have your hubs locked, you should be in 4WD.

-Chuck

What? You have hub selectors because of gear oil? Umm... No. The wheels are spinning freely without the hubs locked in, hubs locked in engages the axle shafts. Now you have axle shafts, differential, and drive shaft being spun causing drag. The only way I can think of that can feasibly cause you to spin out when coming out of 4 wheel drive with the hubs locked is the torque load is now suddenly changed. Not to mention loss of traction in the front, the reason why you were in 4 wheel drive in the first place.

Your wheels are still turning, whether or not you have traction, as long as you aren't mashing the brakes.

 

[wikallen]

My response to a couple of answers here.

 

[stumps]

Did you have water (turned ice) in that front end? I too have been driving for over 20 years, except for '91-'94 when I was stationed in the UK, I have never lived any farther south than Kansas. This past week the morning lows have been below zero and we have had snow packed roads. My driveway from the house to the street is packed snow, downhill with a curve right out of the parking area, my Jeep has nearly bald mud terrain tires and no locking hubs on the front, the front diff is spinning full time, my front end has never locked up from cold/thick oil. Right now as it sits I can put it in drive and lightly apply the brakes and the fronts will lock and slide as I idle and the rears will continue to push until I lay on the brakes hard enough to stop the rear wheels. Thats how little traction my front have.

I would guess you had some other mechanicle problem with your front end to cause you to lose control.

Well, you would guess wrong then. The truck was brand new, had brand new M/S tires, I was less than 1/2 mile from my house, and the front differential really had no time to warm up. Its gears were churning very thick gear oil. Since we are blessed with very cold weather, try jacking up a front wheel and turning it by hand with and without the hubs locked. I think you will start to understand.

-Chuck

 

[DokWatson]

Well, you would guess wrong then. The truck was brand new, had brand new M/S tires, I was less than 1/2 mile from my house, and the front differential really had no time to warm up. Its gears were churning very thick gear oil. Since we are blessed with very cold weather, try jacking up a front wheel and turning it by hand with and without the hubs locked. I think you will start to understand.

-Chuck

Yeah, its harder turning another few hundred pounds of metal along with the tire isn't it?

 

[stumps]

What? You have hub selectors because of gear oil? Umm... No. The wheels are spinning freely without the hubs locked in, hubs locked in engages the axle shafts. Now you have axle shafts, differential, and drive shaft being spun causing drag.

And that drag is trying to stop the front wheels from rotating. If you have very little traction, that drag will succeed in stopping the wheels from rotating long before they otherwise would have with the hubs unlocked.

The only way I can think of that can feasibly cause you to spin out when coming out of 4 wheel drive with the hubs locked is the torque load is now suddenly changed. Not to mention loss of traction in the front, the reason why you were in 4 wheel drive in the first place.

Clearly there was a sudden change in torque load, and that caused the front wheels to stop rotating. When they stopped rotating, they were then skidding, and when your wheels are skidding, they lose all steering action.

Your wheels are still turning, whether or not you have traction, as long as you aren't mashing the brakes.

Uhmm, no.

A front pumpkin full of molasses thick gear oil will act like front wheel brakes. On ice, the front wheels will stop rotating, and when they do, you lose all steering action.

That is why I said that if you are driving in a road condition that needs your hubs locked, keep the vehicle in 4WD. If you don't need 4WD, leave the hubs unlocked. It is a warning based on a bad experience I once had. You can heed it or not as you wish.

-Chuck