LMTV and Deep Water Fording

[Webrep]

We have been using our LMTV to assist in water rescues here in MO but I was curious on what the military manual says on deep water fording in the LMTV. I have been all through the TM's and not much is mentioned except testing fan clutch switch. Anyone got any experience in using the LMTV in deep water? Deep is relative but so far we have kept it above the fan. With the fan clutch on should i see the fan stop moving? Thanks for the info, trying to set some limits on usage.

 

[Suprman]

The dash switch will keep the fan from coming on. Designed for use in water where the water flow is expected to provide the cooling. There are vids online of LMTVs driving thru water until the intake went under and they stalled out. The electrical is very prone to corrosion so going under water to the point where the dash is submerged will probably cause issues over time and make for an unreliable truck. There is a plug on the bell housing that's supposed to be installed before going thru water. I personally find it odd that the exhaust is so low compared to my other mil trucks. If I had to go thru deep water I would just do it and worry about the consequences later. I can get another truck.

 

[MaiNiaK]

I just shut my fan off.
It would be a good idea to check your fluids after your done doing your water rescues.
But I've never found any water in mine.


I only go in till water is at the bottom of the doors. I've also shut the motor off sitting that deep (spaced it) didn't even faze it. The truck started right up.

Now this is a little overboard.
http://youtu.be/C6b54bZepoA

 

[scottmandu]

I just shut my fan off.
It would be a good idea to check your fluids after your done doing your water rescues.
But I've never found any water in mine.
View attachment 601476View attachment 601477

I only go in till water is at the bottom of the doors. I've also shut the motor off sitting that deep (spaced it) didn't even faze it. The truck started right up.

Now this is a little overboard.
http://youtu.be/C6b54bZepoA

Do the occupants of those trucks have scuba gear on?

 

[MaiNiaK]

I don't belive so.
you can see one bail with a camera.

 

[Suprman]

As soon as the water is higher than the air intake stack then they are done. There was a 1083a1 sold off in PA last year that had been fully submerged. Maybe one of the trucks in the vid.

 

[Webrep]

Spent some time in the TM's today and I see info on 50" and 60" max depth with fan off and bell housing plug installed. But I couldnt find operation instruction on the fan switch. If the LMTV is running and I switch off the fan should it stop spinning or will it continue spinning until it hits water resistance?

 

[Suprman]

Going into water you should have the plug in and fan off. The plug should not be left in after leaving the water though. Fan switched off it will not spin. The fan only comes on with a temp sender its not always on.

 

[Webrep]

Ok we had the LMTV running for an hour or s, out getting paint job quotes, discovered the fan switch and switched it off. We then looked under the cab and the fan was still running. In that scenario should it keep running?

 

[Suprman]

It will spin a bit but should not be running. It's loud when running you can't mistake it. The assembly spinning with the fan off will cause the fan to spin a bit.

 

[Webrep]

thanks I will check it again soon...

 

[Lmtv772]

As soon as the water is higher than the air intake stack then they are done. There was a 1083a1 sold off in PA last year that had been fully submerged. Maybe one of the trucks in the vid.

Those two in the video are M1078 I think I saw one of them on govplanet last year.

 

[turnkey]

Iffn you run it underwater ...buy a new ruck ...to much corrision and repair work...everytime you go under that adds about 3 hours maintance to the rig in repair work....But if you like electrica shorts go for it...Best of luck on this one.

 

[MaiNiaK]

You all must of got some lemons or something... (Or over complicating things).
Im sittin back installing a couple door seals, fixed a door that needed no parts, replaced a heater unit that just had a stuck fresh air vent and needed to add some fluid to my hydrolic pump to tilt my cab.
ok maybe I should knock on wood.. Nah... It's just a truck...

 

[tennmogger]

Has anyone found where the various vents and breathers terminate? Do they go to a common point? There are definitely breathers on both axles and on the bell housing. I found the bell housing vent terminates at a little breather valve on the end of a hose.

Tracing the breather hoses from the axles has been difficult without breaking the hose bundles, and I certainly do not want to do that. Have those of you who have parted out trucks happened to notice where those breather hoses terminate?

I think my breather hose on the front axle is plugged and I can't find the 'other' end.

thanks

Bob

 

[Suprman]

I haven't gotten into taking a truck that far apart. Engine and all the little cab parts are what resells quick. Why don't you disconnect it coming off the axle and blow some air into it.

 

[tennmogger]

Hi Will, I did put air into it and no-go, not much anyway. I used a regulator and put about 20 psi of shop air on it, not wanting to do damage downline. So now I have to find out where that hose goes. On the front axle there are two vent/breather holes on the right side of the axle housing (top). One goes to the right portal, the other goes inside the right hand frame rail and heads rearward, to where, can't determine.

I even got my daughter to come over to listen. I can't hear high pitches, but she can, and heard nothing.

I have been through the -10, -20 (5 volumes), -24, -34 (two volumes) and no luck with a 'breather' diagram. Has anyone seen one?

BTW, the manual refers to these as breathers instead of vents. But this brings up another issue, the manuals, I can never find what I want in a logical manner. Any body else think they stink wrt searchability?

Bob

 

[Suprman]

Do you know if air can be blown thru the rear axle vent? The manuals are not big on diagrams they are more flow chart troubleshooting. Personally I like diagrams I can lay out and devise my own troubleshooting. On the older trucks there are vents on the axles. When those vents are blocked up you will get fluid bleeding out of the weakest seal points with expansion. I can try to unbundle some stuff and see where lines go but it's been cold here in CT.

 

[Suprman]

It looks like the vents go into the air brake system or the ctis and to the quick release valves.

 

[tennmogger]

Nice diagram! Oddly, my 24P manual, figure 142, is different. It relates to CTIS but does not show the breather lines like this diagram does.

The way I interpret the diagram, and the physical layout (which match, so far I think) is: If you look at the point #30, near top right of diagram 142, that 'T' is the gathering point for the breathers. The left reduction housing has a hose directly to that "T", but on the right side the reduction housing breather hose comes to the axle housing, then the breather hose #32 goes to that #30 "T". That's where I got to, tracing hoses. It is the third leg of that "T" that is the mystery.

What I do not understand is any relationship of the axle vent to the CTIS, if there is a relationship. If CTIS pressure ever hits the axle housing, big problems!! The pinion seal is probably 5" in diameter. Calculate how much force 110 psi of air can put on that surface and you see why there can never be CTIS pressure in the axle housing.

Well, on my truck, I am convinced there is a fault that lets CTIS pressure hit the axle housing, and therefore the pinion seal, and blows it out. It gets literally blown out of the housing up against the back of the pinion yoke. This happened for the third time 3 mornings ago. But I do not want to hijack this thread. Up until now the subject has been fording, which certainly does rely on venting and breathing system. My truck had another seal issue, too, involving an updated seal and dual seals that destroyed each other (other thread). http://www.steelsoldiers.com/showthread.php?146118-LMTV-Front-Diff-Pinion-Seal

thanks for the feedback! Wish I were there to check out your partially stripped chassis.

Bob