Front Hubs & Towing

Front Hubs & Towing

BusaDave9

Always Off-Roading Jeeper
Posts
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Location
Durango, Crawlarado
Vehicle(s)
1979 Jeep CJ5 with 304 V8, T18 Transmission, Dana 20 Transfer case with TeraLow 3:1 gears, 4.88 axle gears, Detroit Locker up front and Ox Locker in back with 1 piece axle shafts, 36" SuperSwamper SX Tires, Shackle reversal, MileMarker Hydraulic winch, MSD 6A ignition.
I have always thought the front hubs should be unlocked when getting towed. This keeps the front axle and diff from rotating.
Then I got TeraLow gears for my transfer case and the instructions say when towing to put the transfer case in neutral and lock the front hubs. They underlined it for emphasis.
Of course the gear ratio in the T Case shouldn't make the difference. Does anyone know why it would be better to have the front hubs locked while towing?
 
I'm just guessing since I have no experience with the TerraLow gears, But I'd imagine the design requires the front and rear driveshafts to rotate at the same time for some reason. Don't forget the rear driveshaft (unless you disconnect or remove it completely) will still be rotating the gears in the TC. So my guess is there is an oiling requirement for the front gears, nessitating the front hubs be locked.
Whatever the reason, If they say it (and underline it even) then I'd just do it. Your drivetrain has changed from stock, so the normal requirements/instructions have changed and are void.
 
Originally I thought getting towed with the hubs unlocked was like driving in two wheel drive.
So then I emailed the guys at TeraFlex the makers of the TeraLow Transfer kit. They explained it to me. Whenever you drive the jeep the input gear is always turning. This is rotating gears on every shaft. Even if they are not transferring power they are transferring oil throughout the transfer case. I made this gif to illustrate how the transfer case works. Any gear that is red is transferring power. Any gear that is blue is free-wheeling on it's shaft. Black gears are not rotating. When you shift a transfer case there are two gears you are sliding on their shafts. These sliding gears either lock themselves onto the shaft if they are moved to the front of the transfer case. Or if they move to the rear they mesh with the idle gear.
Four wheel drive low is confusing. Keep in mind the main drive shaft from the transmission is rotating faster than the out rear drive shaft. Power is transferred from the transmission gear to the idle gear and then back to the two drive shafts.
Many other gear driven transfer cases, such as the Dana 300 , are made this way. This is why you should always have the front hubs locked when getting towed. Either the front drive shaft OR the transmission needs to be rotating the gears in the transfer case. The rear drive shaft can't rotate the necessary gears.
This dispels a common misunderstanding. Lock your hubs when getting towed.

dana_20.gif
 
I do full float conversions on the rear axle and disco both sets of hubs.
 
I do full float conversions on the rear axle and disco both sets of hubs.
That's a good idea. I think those full floating conversions were more common in the '80s. They also help when you have problems with your rear end when you are away from home. You can lock your front hubs and drive home in front wheel drive. Twin shift levers for the transfer case also helps avoid rotating a broken diff.
 
That was an excellent post. The illustration is nice quality work. Even a brain dead monkey like myself could follow it. :D

:notworthy:
Originally I thought getting towed with the hubs unlocked was like driving in two wheel drive.
So then I emailed the guys at TeraFlex the makers of the TeraLow Transfer kit. They explained it to me. Whenever you drive the jeep the input gear is always turning. This is rotating gears on every shaft. Even if they are not transferring power they are transferring oil throughout the transfer case. I made this gif to illustrate how the transfer case works. Any gear that is red is transferring power. Any gear that is blue is free-wheeling on it's shaft. Black gears are not rotating. When you shift a transfer case there are two gears you are sliding on their shafts. These sliding gears either lock themselves onto the shaft if they are moved to the front of the transfer case. Or if they move to the rear they mesh with the idle gear.
Four wheel drive low is confusing. Keep in mind the main drive shaft from the transmission is rotating faster than the out rear drive shaft. Power is transferred from the transmission gear to the idle gear and then back to the two drive shafts.
Many other gear driven transfer cases, such as the Dana 300 , are made this way. This is why you should always have the front hubs locked when getting towed. Either the front drive shaft OR the transmission needs to be rotating the gears in the transfer case. The rear drive shaft can't rotate the necessary gears.
This dispels a common misunderstanding. Lock your hubs when getting towed.

dana_20.gif
 
Care to elaborate on that? what does it take?
If you don't mind me answering for you, BajaEdition. A full-floating rear axle kit will allow you to install locking hubs in back. This way you can unlock all four tires and the only things moving when getting towed will be the wheels.

There are two types of axles: full floating and semi-floating.
Jeeps and light duty trucks come with semi-floating axles. The axle shaft sticks out of the axle tube and of course the wheel is bolted to the end of the axle shaft. This configuration puts the weight of the vehicle on the axle shaft.
Heavy duty trucks have full floating axles. In this configuration the rear hub is mounted to the axle tube. This puts the weight of the truck on the axle tube. The only strain on the axle shaft is the rotational force driving the truck. This is a much stronger setup. You can identify a full-floating axle because it has 6 or 8 bolts on the hub itself.
full_floating.jpg
 
thanks Busa, the pic you show is full floating but still uses a drive flange so it does not disco, I put a set of warn hubs such as are the front axle also, this way I can disconnect the axle same as the front. With both axles discoed I can flat tow without worrying about the tcase or tranny.
I actually started this on a jepp I had because I had busted an axle and had to get towed out. I run a lot of trails by myself so I decided I needed a way to get home with a broken axle with no one around. The benefit of flat towing was secondary. I figured that out one time I was about to go tow my Jeep to a show. (use to have a Tuxedo Park Park that I would show) It never got any prizes but a lot of guys would ohh and ahh over it.
As CJ owners we usually have full floating axles in the front come with our Jeeps when we buy them. guys with TJs and JKs are not so fortunate and have to convert. I know that warn has even stopped making kits for this conversion as it is not as popular as it used to be.
 
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Sounds like more work and $ even if parts were still available. I guess I'm just gona pull it around the way they tell you too, do kinda worry about having the thing go into gear on a pothole or something but it would have engage the the trans. and the T case to grenade the motor. Not very likely but have heard of at least one guy who got to his destination to find a rod through the block :(.
More in line with the thread-I have a CJ3b that has been towed all over the place and the hubs were allways left free because we did'nt know any better.
 
Yes, a full floating kit and hubs for the rear can get expensive. CJ owners think it's worth while because we have to get rid of the factory 2 piece axles if we want to do any hard off roading.
You could also remove the rear drive shaft when getting towed. Then the only thing rotating would be the rear end. Removing the drive shaft can be a pain for a short trip but if you will be towing long distance it's worth it for the peace of mind.
 
This is a good discussion for me right now!
I got the '81 Laredo to tow behind our Motorhome. There has been numerous discussions about this on numerous sites and usually disagree .I understand that the Transfer Case may not get proper Lubrication when the Output Shaft is Turned rather than from the Input Shaft.
I then bought an Owner's Manual for my 1981 CJ7 . It states to; shift the Transmission into Gear and the Transfer Case into Neutral, stop every 200 miles and run the Engine for about a minute with the Transmission still in Gear and the Transfer Case in Neutral. It doe state that Cherokee, Truck and Wagoneer should have the Hubs Locked.
I talked to Larie at Jeeps R Us about this and he says to put the Transmission in Gear, Transfer Case in Neutral and Un-Lock the Hubs, he then said to just stop every 300 miles and run the Engine with the Trans in Gear and the Transfer Case Un-Locked to Lubricate the Transfer Case.

I am still confused about this but I would rather not have both Drivelines Turning when I am Towing the CJ7 . I then went looking for a Full Floating Axle Conversion; Warn sold this to Randy's Ring and Pinion. I talked to Randy's Ring and Pinion and they will not be building this kit.

I would like to do a Full Floating Axle Conversion and have some older Warn Kits at some time soon. It does sound like I need to talk to BajaEdition about a Full Floating Conversion.
 
That's what I was thinking, might be worth the 10 min. to drop/install the driveshaft. Our main destination from home is 300 mi. +- or about 6hrs. Be nice not to have everything whirling away at 65 mph.
 
When I said to lock your hubs when getting towed I was talking about the Dana 20 transfer case but it also applies to many other gear driven transfer cases such as the Dana 300 and Dana 18. I don't think it applies to some chain driven transfer cases such as the QuadraTrac that came in some jeeps in the '80s. I wonder if the manual you have is referring to the QuadraTrac .
 
most of the chain driven transfer cases came with semi floating axles (TJ) or vacuum disconnect (YJ) so the front was spinning anyway.

I have to agree with the cost of a full floating kit, around 800 clams with hubs, and then labor, but the benefits are huge. Besides towing, and getting the weight off the shaft, you can also disconnect a shaft if you break it and drive home (If you have a locker). I really do not suggest this to everyone, but If you want the benefits it is there. Just getting the weight off the axle is like upgrading to bigger shafts.
 
You all can do it how you like, but I towed my '74 (T-150 3 speed and Dana 20 TC) 2100 miles 1 way at Hiway speeds (+) over 3 days when I moved across country. This was after extensive research and reading a few factory manuals.
I unlocked the front hubs, put the trans in HI gear and left the transfer case in neutral. The driveshafts both stayed in place.
The only problem I have to report to this day is the Speedo failed somewhere along the way (I guess it didn't like the 70 MPH speeds!).
So for me (and my setup) I will continue to do this when I flat tow.
 
Any reason for the trans. in high gear?
 
to keep the gears in the trans. from turning, and galling/burning up while being towed.
I'll see if I can find the explanation I wrote out once (while it was fresh in my mind) and re-post it...

EDIT:
Found it...
Actually (and this was a point raised and answered on another forum by a transmission guru of sorts) the reason is this...

On certain transmissions-T/Cs (My Dana 20 for a fact, I dunno about the others cause I didn't own one at the time) If you flat tow with the driveshafts intact what happens is this:
As the wheels turn the driveshaft, it turns the output shaft of the transfer case, and it turns the gears in the case...lubricating said gears. BUT it also turns the main gears in the transmission, just by the force of the gear oil rotating the gears and the input shaft of the T/C (thru 'hydraulic' pressure).
If the transmission gears are allowed to rotate enough, it can dry the bearings out enough to gall and eventually seize the bearings on the shaft.
SO, to eliminate that, you put the T/C in neutral (allowing all the gears to get lubrication thru 'hydraulic' rotation) and the transmission in gear, (locked against the engine's compression, and I use 3rd cause if something were to happen and it suddenly went into gear, the sudden skidding will be less severe than if it were in 1st...) to eliminate the main gears from turning (resulting in failure).

Is that clear as mud?
smile.gif
 
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ok interesting thread....i have an AMC20 with full floating axles. is this truly a stronger setup? also, does this require 1 piece axles? i bought the jeep with this setup and have been considering inspecting the insides soon to find out if its one piece axles or the POS 2.... want to make the jump from 33s to 35s so wanna upgrade the 20, if i cant pick up a 44 for cheap!!
 

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