Interaxle lock

[gladman]

Can someone tell me the proper use of the inter axle lock? My mechanic told me never to drive over 25mph with it on, it's only smart to use it when in a yard backing up or starting out.

A tow truck guy told me I can use it when on ice or snow, especially when trying to slow down with the engine brake on.

Advice please.

I thought you could get them a little over 25 with it on but i know its a pretty low limited speed and it will burn the differential up if you abuse it. I have never locked one in for anything other than trying to bang my way under a heavy trailer on really really slick snow covered lots. I am sure others have used it for more but thats the only thing i have ever used it for. Just my 2 cents but I cant even think it would be a good idea for you to throw the jake on if its that slick anyway,maybe get away with it if you are pretty heavy but if you are empty and on ice....cant say the jake is a good idea even if you have the diff lock kicked in. Maybe i'm wrong on that chime in if you disagree.....I'm no experet...just dont seem like a good idea

[no_worries]

I'll lock it up when driving on slick roads, never over 35 and never using the Jake, but as Jager said that's due to the slick roads not the fact that the interaxle is locked.

Many people think that locking the interaxle gives you power to both axles which is incorrect. You've always got power to both axles. However, if a wheel starts spinning and you're unlocked all the power is transferred to that wheel, meaning you don't go anywhere until that wheel regains traction. With the interaxle locked in, there is no power transfer so the rest of your wheels stay powered. Common sense tells you which is better in slick conditions.

My book and Western Star both told me I can lock the differential in at any speed and go as fast as I want. There is no restrictions. I've used mine many many times at speeds greater then 50 turning it on and off. Maybe other rear ends are different but I'm looking at my manual right now.

My book and Western Star both told me I can lock the differential in at any speed and go as fast as I want. There is no restrictions. I've used mine many many times at speeds greater then 50 turning it on and off. Maybe other rear ends are different but I'm looking at my manual right now.

I'm not gonna argue with you on what your truck manual says but that is very contray to everything i have ever heard or been told by my companies. I guess it can be different on different trucks....but all 3 companies i have been with, we have been told not to do that.....on 3 different brands of trucks. Maybe they are just overly cautious.
Steve, i do have a question though.....if you were driving in something that was slick enough that you felt you needed it.....what were you doing going in excess of 50 mph....not trying to be a know it all traffic cop...but that seems kinda contrary to conditions, maybe i am just a grandma driver when its that slick.

[Kranky]

The main concern is: Never engage the power divider lock when a wheel or wheels are spinning!

That would be the equivalent of jamming a transmission in gear while stopped without depressing the clutch.

If the truck is stopped, or if the truck is moving with no wheel spin, you can lock and unlock the power divider lock whenever you want, as there is no relative motion between the sliding clutch teeth which engage the lock under those conditions.

Don't forget to disengage the lock when driving under normal conditions on dry pavement, or the rear axles will experience "torque windup" due to the drive wheels attempting to turn at different speeds when steering and turning corners. (this is similar to what happens if you drive a 4WD pickup on a hard road in 4 wheel lock).

[Part Time Dweller]

Instructions for the inter axle lockout/ Power divider. Provided by Eaton Dana.

http://www.roadranger.com/ecm/groups..._axdr-0126.pdf

Use lockout when approaching: ice, snow, mud, wet surfaces, or loose terrain.

Lockout Operation
1. Temporarily release the accelerator pedal. This interrupts the torque
applied to the inter-axle differential allowing easy engagement or disengagement
at any speed.

2. Flip the lockout selector valve to lock (engage) or unlock (disengage)
the lockout.

Remember:
• Engage lockout at any speed with accelerator released. Never
engage lockout when wheels are slipping.
• Use only under poor traction. Do not operate truck with lockout
“engaged” on dry pavement.

How it works;

Tandem axles will rotate at different speeds when cornering, driving over
uneven road surfaces or when equipped with different tire sizes.
The inter-axle differential is simply a mechanism that lets one axle rotate faster
or slower than the other. Under normal conditions it splits the torque evenly
between the 2 axles.
When extra traction is needed under adverse road conditions, you can lock out
the inter-axle differential. With the lockout engaged (LOCK position), the interaxle
differential acts as a solid shaft and does not compensate for differences
in axle speed, but directs the torque to the axle with the most traction.
With the lockout disengaged (UNLOCK position), the inter-axle differential
operates normally.

There also is a differential lock that locks the rear ends side to side. This is usually not installed on an OTR truck, but can be. This will be a seperate control from the power divider. This is the one you can't use over 25mph, and trust them when they say you will have severe understeer with it on.

Instructions for differential lock, Provided by Eaton Dana
http://www.roadranger.com/ecm/groups..._axdr-0130.pdf

The Dana Drive Axle Wheel Differential Lock is an air-actuated clutch which
positively locks the differential gearing in the rear axle. When this clutch is
engaged, power flows to the tires without any differential action, giving each
wheel all the torque the road conditions will permit.

The Wheel Differential Lock is engaged by a cab-mounted valve, causing the
clutch to move in or out of engagement. This motion also trips an electrical
switch used to activate a light in the cab or sound an audible device, indicating
that the Wheel Differential Lock is engaged.

WARNING: Do NOT use your Wheel Differential Lock when traveling
downhill

WARNING: Do NOT use your Wheel Differential Lock at speeds over
25 mph

Engage
1. Flip the control lever to the “Lock” position, either while the vehicle
is stationary, or while moving at a steady speed under 25 miles per
hour without the wheels slipping (spin out).
2. Let up momentarily on the accelerator pedal to relieve torque on the
gearing and fully engage the clutch.
3. When the differential lock is engaged, the indicator light will be on, or
an audible signal will sound.
4. When the differential lock is engaged, the vehicle will understeer,
requiring a longer turning radius for a given turn.

Disengage
1. To disengage the Wheel Differential Lock, flip the control lever to
“Unlock”.
2. Let up momentarily on the accelerator pedal to relieve torque and
allow the clutch to disengage.
3. When the differential lock is disengaged, the indicator light and/or
audible signal will go out.
WARNING: Engage Wheel Differential Lock ONLY when vehicle is
stationary, or moving without wheel slippage.

Important To Remember
When engaged, the Wheel Differential Lock will cause the vehicle to understeer,
meaning that the vehicle will not turn as quickly, and more steering
effort will be required.
Use your Wheel Differential Lock only at speeds less than 25 miles per
hour; at higher speeds, the understeer handling characteristics could be
dangerous.
The differential lock should be engaged only when the vehicle is stationary,
or moving without wheel slippage (spin out).
This system should only be used when poor traction is encountered; it
should be disengaged under normal traction conditions.

Thanks Dweller. I was just going to say screw it and go my merry way and let everyone tell stories instead of actually PICKING UP A MANUAL AND ACTUALLY READING IT!!!!!!!!!!!!!

[rvrjr7]

the only time i use my axle lock is when i am stuck in the snow ice sand or mud i use it to get me moving then i flip it off because i dont want to tear up my equipment 8)

[Fredog]

Can someone tell me the proper use of the inter axle lock? My mechanic told me never to drive over 25mph with it on, it's only smart to use it when in a yard backing up or starting out.

A tow truck guy told me I can use it when on ice or snow, especially when trying to slow down with the engine brake on.

Advice please.

the switch plate on my axle lock says.. shift at any speed except if a wheel is spinning.

Thanks Dweller. I was just going to say screw it and go my merry way and let everyone tell stories instead of actually PICKING UP A MANUAL AND ACTUALLY READING IT!!!!!!!!!!!!!

I dont think anyone told any STORIES....we are going by what we have learned and were told, if this qualifies as making up a story...sorry I didnt mean to lie to you all even though i didnt know i was making it up and lying.

I am still curious just as to why you would lock that in going over 50 mph if you thought it was actually slick enough to use it. This is not a smart ass question I am just very curious about this....maybe i can learn a new thing or 2 about driving in slick conditions on this thread.

[Fredog]

Thanks Dweller. I was just going to say screw it and go my merry way and let everyone tell stories instead of actually PICKING UP A MANUAL AND ACTUALLY READING IT!!!!!!!!!!!!!

I dont think anyone told any STORIES....we are going by what we have learned and were told, if this qualifies as making up a story...sorry I didnt mean to lie to you all even though i didnt know i was making it up and lying.

I am still curious just as to why you would lock that in going over 50 mph if you thought it was actually slick enough to use it. This is not a smart ass question I am just very curious about this....maybe i can learn a new thing or 2 about driving in slick conditions on this thread.

last winter, I was driving on a 2 lane road in the middle of nowhere about 11 at night, the weather was dry and the road looked fine, when I went to slow down for a curve, my tractor started to go sideways. I recovered and and then I locked in the axles. I figured there must be icy patches, I dont know if it did any good to turn it on, but it made me feel better. then I went on to the customer and got stuck in the snow on the rxr tracks, (luckily, their private tracks) but that's another story

Ok, I went and got out the old freightliner manual....different things for different rear ends and traction control devices....the only one in my manual that specificly says its ok to kick in at any speed is the Dana Spicer axles with Controlled Traction Differential.

On the other hand, Dana Spicer Interaxle Differential Lockout, different from controlled traction differential, specificly states, Engage only when stopped or at slow speeds and never on dry pavement or for prolonged periods of time.

On Meritor, the one that states specificly that you should lock in only at a stand still and never over 25 mph is the [b]Main Differential Lock[/b, different from Interaxle Diff lock whichis i guess what we were thinking about on the beginning of the thread.

The only one in the manual that specifies that it is ok to use at any speed is the Dana Spicer with Controlled Traction Differential which is apparently a different thing from interaxle diff lock.

Long story short, everybody was part right and part wrong...just depends on which option your truck is equiped with.

The one constand with all of these things is that none of them are really recomended for exteneded use and nver on dry pavement...and they do cause extra wear on the drive train....So Just take a peek in your manual like stated above, i did that and learned a few things...now i just have to figure out if i have a Dana Spicer or Merritor set up.

I dont think anyone told any STORIES....we are going by what we have learned and were told, if this qualifies as making up a story...sorry I didnt mean to lie to you all even though i didnt know i was making it up and lying.

Sorry JaggingBoomber, didn't mean for it to come out that way. Most of the time what I really want to say doesn't come out in my posts.

no problem...hey At least i went and got out that manual and did do some reading instead of just arguing my side. I always went by what the company told us about using the darn thing and it just didnt occur to me to read up on it since I very very rarely touch it anyway. Good info to have if you are in the snow alot.

[GhostCaptain]

Last year when I got my CDL and not much experience with trucks, I was traying to leave my yard and the rear wheels started spinning in some mud, engaged the diferencial lock,got out and completelly forgot to unlock it until 400 miles later in Houston,Texas, nothing happened to the differentials

[Doghouse]

I hope I didn't ruin mine. Today when I picked up my trailer I had to use it in the snowy yard and then I drove 9 miles on dry pavement before I noticed that I left it on.

[Mackman]

i know in my MACK with the diff. lock on a loud azz buzzer comes on and stays on intill you take the diff. lock off.

[Orangetxguy]

Instructions for the inter axle lockout/ Power divider. Provided by Eaton Dana.

http://www.roadranger.com/ecm/groups..._axdr-0126.pdf

Use lockout when approaching: ice, snow, mud, wet surfaces, or loose terrain.

Lockout Operation
1. Temporarily release the accelerator pedal. This interrupts the torque
applied to the inter-axle differential allowing easy engagement or disengagement
at any speed.

2. Flip the lockout selector valve to lock (engage) or unlock (disengage)
the lockout.

Remember:
• Engage lockout at any speed with accelerator released. Never
engage lockout when wheels are slipping.
• Use only under poor traction. Do not operate truck with lockout
“engaged” on dry pavement.

How it works;

Tandem axles will rotate at different speeds when cornering, driving over
uneven road surfaces or when equipped with different tire sizes.
The inter-axle differential is simply a mechanism that lets one axle rotate faster
or slower than the other. Under normal conditions it splits the torque evenly
between the 2 axles.
When extra traction is needed under adverse road conditions, you can lock out
the inter-axle differential. With the lockout engaged (LOCK position), the interaxle
differential acts as a solid shaft and does not compensate for differences
in axle speed, but directs the torque to the axle with the most traction.
With the lockout disengaged (UNLOCK position), the inter-axle differential
operates normally.

There also is a differential lock that locks the rear ends side to side. This is usually not installed on an OTR truck, but can be. This will be a seperate control from the power divider. This is the one you can't use over 25mph, and trust them when they say you will have severe understeer with it on.

Instructions for differential lock, Provided by Eaton Dana
http://www.roadranger.com/ecm/groups..._axdr-0130.pdf

The Dana Drive Axle Wheel Differential Lock is an air-actuated clutch which
positively locks the differential gearing in the rear axle. When this clutch is
engaged, power flows to the tires without any differential action, giving each
wheel all the torque the road conditions will permit.

The Wheel Differential Lock is engaged by a cab-mounted valve, causing the
clutch to move in or out of engagement. This motion also trips an electrical
switch used to activate a light in the cab or sound an audible device, indicating
that the Wheel Differential Lock is engaged.

WARNING: Do NOT use your Wheel Differential Lock when traveling
downhill

WARNING: Do NOT use your Wheel Differential Lock at speeds over
25 mph

Engage
1. Flip the control lever to the “Lock” position, either while the vehicle
is stationary, or while moving at a steady speed under 25 miles per
hour without the wheels slipping (spin out).
2. Let up momentarily on the accelerator pedal to relieve torque on the
gearing and fully engage the clutch.
3. When the differential lock is engaged, the indicator light will be on, or
an audible signal will sound.
4. When the differential lock is engaged, the vehicle will understeer,
requiring a longer turning radius for a given turn.

Disengage
1. To disengage the Wheel Differential Lock, flip the control lever to
“Unlock”.
2. Let up momentarily on the accelerator pedal to relieve torque and
allow the clutch to disengage.
3. When the differential lock is disengaged, the indicator light and/or
audible signal will go out.
WARNING: Engage Wheel Differential Lock ONLY when vehicle is
stationary, or moving without wheel slippage.

Important To Remember
When engaged, the Wheel Differential Lock will cause the vehicle to understeer,
meaning that the vehicle will not turn as quickly, and more steering
effort will be required.
Use your Wheel Differential Lock only at speeds less than 25 miles per
hour; at higher speeds, the understeer handling characteristics could be
dangerous.
The differential lock should be engaged only when the vehicle is stationary,
or moving without wheel slippage (spin out).
This system should only be used when poor traction is encountered; it
should be disengaged under normal traction conditions.

Power Dividers today are far and away superior to the power dividers of the 60's, 70's and early 80's. Technology ...go figure.

Now...the Wheel Differential Lock..that is sweet, if you are chained up, pulling 105,000 pounds, and climbing a mountain. It makes it tough though, if you have it engaged and try to turn a 90 degree corner. Lot's of crow hopping, even at slow crawl.

[allan5oh]

Yup you definitely don't want to have this thing engaged while it's slick out and you're going around corners. You greatly increase your odds of jacknifing under power.

It's the axle lock that you don't want to leave engaged. Most trucks nowadays will disengage the axle lock automatically at about 15 mph.