Middle axle only use in rear

[snowtrac nome]

Im no expert on the fmtv system but I believe the differential lock is only for the inter axle power divider I think the rest of the differential is still open. If that is the case and you are doing this to lessen driveline angles than the lock would have to be applied all the time or power transfer would be to the rear axle you no longer have.

 

[coachgeo]

Im no expert on the fmtv system but I believe the differential lock is only for the inter axle power divider I think the rest of the differential is still open. If that is the case and you are doing this to lessen driveline angles than the lock would have to be applied all the time or power transfer would be to the rear axle you no longer have.

that is correct.... the lock will have to be activated full time. One remaining question is how that activation happens... does it happen with a "burst" of high air pressure to turn it on, and hit it again to turn it off (like a light switch.... you hit it once and it turns on. hit it again to turn it off).... or via a steady flow of air pressure to hold it on. (like a momentary switch.... you hold in place to keep a light on and release of switch it goes off)

 

[coachgeo]

If you look at when the diff lock is applied to the MTV it is when you put it in mode if I remember. Full power to all axles front/rear.
When I have used the diff lock in any truck it was only to come out of something nasty. It was then switched off as soon as the truck has reached hard pan. Myself I would not drive with the diff lock in gaged at highway speeds.

basically correct... but that is not applicable to this application as discussed earlier in thread.... where it must be on "all the time". Thus; one remaining question now is..... how is it turned on??? With steady air pressure or with a short duration blast of air pressure? ( as well is the other couple plumbing questions )

 

[ramdough]

Im no expert on the fmtv system but I believe the differential lock is only for the inter axle power divider I think the rest of the differential is still open. If that is the case and you are doing this to lessen driveline angles than the lock would have to be applied all the time or power transfer would be to the rear axle you no longer have.

I believe you are correct. The axle diff will be open. The drive angle will be higher. You probably have to have the power divider locked all of the time.

This seams like a lot of work to only change the drive angle. It also makes the rear axle a lot heavier than before.

Is there an angle I am missing, or why go through so much effort?




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[coachgeo]

I believe you are correct. The axle diff will be open. The drive angle will be higher. You probably have to have the power divider locked all of the time.

This seams like a lot of work to only change the drive angle. It also makes the rear axle a lot heavier than before.

Is there an angle I am missing, or why go through so much effort?




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been discussed already.... doing it cause I want to lol. Maybe it is over reaction from 6grand transmission repair... maybe it isn't.... but it is happening...

and again.. yes as was mentioned already.... the power divider will have to be locked..... Now back to the remaining questions... of:

Tee location, hardware, air blast to turn on/off.. or steady air pressure to keep on/no air pressure equals- off.

 

[Floridianson]

It will need full time air to stay in gaged and a switch that relieves the pressure when off. Still believe it's not the best thing to run a diff lock at high speeds single or tandem set up.

 

[coachgeo]

It will need full time air to stay in gaged and a switch that relieves the pressure when off. Still believe it's not the best thing to run a diff lock at high speeds single or tandem set up.

thanks will look into a valve that releases air when power goes off... will keep in mind the concern for always locked. Maybe just Lincoln lock it in future?

 

[scottmandu]

It will need full time air to stay in gaged and a switch that relieves the pressure when off. Still believe it's not the best thing to run a diff lock at high speeds single or tandem set up.

True, speed is limited to about 40mph with that diff locked.

 

[coachgeo]

True, speed is limited to about 40mph with that diff locked.

but was that a rule of thumb (or strict rule... which ever it was) because when locked the two rear axles no longer have any differentiating potential/slippage between them and this could potentially cause binding problems. Especially if one axle could not slip in any other way (sand, mud, snow, chirping on pavement etc.)...... same problems one would have if you drove a 4x4 in 4wd on pavement. If so then in my swap this a non issue cause there is no second axle locked with it, thus nothing else to form any binding with.

 

[scottmandu]

I'm just stating the how, not the why.

 

[coachgeo]

I'm just stating the how, not the why.

how? as in when an MTV is in mode does it automatically limit speed to 40mph or is driver training say to limit speed to 40mph? Or both?

Not familiar enough to know where the 40mph thing comes about. Would make sense to have trany computer limit to 40mph in a 6x6 with the two rear axles locked. Read some hints where the mechanics hated drivers having manual Power Dividers lock activation as was more prevalent in the past....... cause drivers would forget and keep them locked too long or when not really needed resulting in tearing up both axles.

 

[Floridianson]

Yep as a tandem to much stress locked and running on anything that is not forgiving mud /snow. As a single believe at highway speeds you are going to get the unit to heat up way to hot. That plow /sander truck when in use would see slow speeds. When I plowed and sanded for the state I don't think I ever came out of second or third on a ten speed. Slow and steady when driving a 15 ton can opener and trying to maneuver around parked cars in neighborhoods.

 

[coachgeo]

Yep as a tandem to much stress locked and running on anything that is not forgiving mud /snow. As a single believe at highway speeds you are going to get the unit to heat up way to hot. That plow /sander truck when in use would see slow speeds. When I plowed and sanded for the state I don't think I ever came out of second or third on a ten speed. Slow and steady when driving a 15 ton can opener and trying to maneuver around parked cars in neighborhoods.

if this is an issue.... the question is what did Oshkosh do when they made these axles the primary axle in the M1078's back in 2007?? I suspect they did away with the air actuated locker and put in a solid blank like a milled lincoln locker. But did they add lube spray bars too orr?

 

[coachgeo]

The diff lock on the 6X6's get the air source from the same source as the fan, so I'd start there.

about to get to this Possibly Wednesday. Any additional specifics on where this Tee may be located? Can anyone grab some pics or have an idea where to look for this in TM. My mind is blank on search words to start with in searching TM's for this airline.

Is the airline to the fan this Tees off of a dry air or a wet air?

 

[Floridianson]

Brass electric solenoid block behind the kick panel below the passenger fuse panel. Dry.

 

[wheelspinner]

Brass electric solenoid block behind the kick panel below the passenger fuse panel. Dry.

On your 1078 there will be a single solenoid. On the 1088 I parted there was a paired solenoid. If I can find it in the garage I'll snap a picture.

 

[coachgeo]

Since this will be full time activated I need to try to avoid whatever solenoid the TCU called up when put in Mode to activate this air locker. I suspect though that particular solenoid wont be in the M1078 and may be the second one in the pair you mention on the 1088.

Then again......putting a second solinoid in there would sure be an interesting theft feature.... can start the truck... but even in drive... without that solenoid opened ... truck would not move lol

 

[Floridianson]

Yea mine has two one for the engine cooling fan one for the axle interlock. Thought you were just going to tap a air supply and run an air switch like on the Deuce front axle engagement or a lift axle air switch. Could just use the correct interaxle air switch that is found on most tractors if you want to disable the axle. Yea don't want have to run in Mode when not needed.

 

[tennmogger]

If this air line has to be on all the time, why add any switches or solenoids? The air for the CTIS and other stuff in the passenger kick panel comes from the Over Pressure Valve off the wet tank, and enables as soon as air is up. Coming off that OPV (aka protection valve) might work fine and it's 'in the vicinity' of where you need it, a lot closer than the cab.

 

[coachgeo]

If this air line has to be on all the time, why add any switches or solenoids? The air for the CTIS and other stuff in the passenger kick panel comes from the Over Pressure Valve off the wet tank, and enables as soon as air is up. Coming off that OPV (aka protection valve) might work fine and it's 'in the vicinity' of where you need it, a lot closer than the cab.

Thanks... makes since..... but not sure if I need dry air or if wet is ok. My guess is need dry air so not to rust up the air solenoid?