Rattle on steady state driving

[aw113sgte]

New to the FMTV, never driven one before so I don't have a good baseline. Truck is 2007 A1R m1096 with 1800 miles. When on the highway when maintaining 50-55 I have what sounds like gear lash noise. Goes away completely on accel/decel. Do these trucks tend to make some noise from the hub gears? I haven't checked the shims yet. The axles and ujoints all feel tight with the "wiggle" test.

 

[NDT]

Hub gears make noise when they are not set up right. Check those and check your driveshaft phasing too.

 

[aw113sgte]

Hub gears make noise when they are not set up right. Check those and check your driveshaft phasing too.

Driveshaft phasing is good, although can't be sure of proper of proper balancing.

 

[Wingnut13]

I seem to have the same issue. 2013 M1078A1 with 14k miles. I can make it happen at 40-50mph if you manage the throttle to lightly load the driveline. My front driveshaft was out of phase when I got the truck. But after that everything feels tight.

 

[chucky]

New to the FMTV, never driven one before so I don't have a good baseline. Truck is 2007 A1R m1096 with 1800 miles. When on the highway when maintaining 50-55 I have what sounds like gear lash noise. Goes away completely on accel/decel. Do these trucks tend to make some noise from the hub gears? I haven't checked the shims yet. The axles and ujoints all feel tight with the "wiggle" test.

View attachment 903431

I bet its those kids on the roof when you get up to highway speed ! They always get quite when you accelerate ! Good looking truck the party now beguines !!

 

[Ronmar]

I would also expect more noise out of them if they were not properly filled with lube, or the end thrust bearing and washer stack has developed issues. Where did you get the truck from? These things went to excess for a reason, and if it has not been gone thru by someone willing to dot the Is and cross the Ts…

something like a magnetic mount microphone or a go-pro with audio might aid you in localizing noises…

 

[aw113sgte]

I would also expect more noise out of them if they were not properly filled with lube, or the end thrust bearing and washer stack has developed issues. Where did you get the truck from? These things went to excess for a reason, and if it has not been gone thru by someone willing to dot the Is and cross the Ts…

something like a magnetic mount microphone or a go-pro with audio might aid you in localizing noises…

Was from MWME, unsure if hubs were checked. Going over the truck some things are checked, other things a bit lacking in maintenance.

 

[GeneralDisorder]

Was from MWME, unsure if hubs were checked. Going over the truck some things are checked, other things a bit lacking in maintenance.

Typical. Trust nothing. Perform a full hub service including CTIS seals, repack bearings, etc. Lots of unhappy purchases from those jokers - overpriced and overrated in the opinion of many. Better off just getting an auction truck or a private party sale and doing it all yourself so you know what your driving.

What's the DOT date on the tires? Anything over 7 years is garbage so subtract however old they are from 7 and that's how long before you need to do the tire dance - so much fun on a 6x6.

Besides the obvious and the trust nothing sentiment - you will want/need to know how all this stuff works anyway so best dive in and see how it's put together.

 

[Third From Texas]

<whispers "ECO hubs">

 

[Wingnut13]

Yeah no doubt that will help…..too many projects in works and everything else is getting too expensive!

 

[aw113sgte]

<whispers "ECO hubs">

Likely in my future.

 

[Xengineguy]

Yep! Pm me will fix you up.

 

[coachgeo]

look close at your MTV truck. Note that portion of the transmission sites above the upper chassis rail. To clear the transmission you will need either a third chassis rail.... or put a dog house in you box to hump over it; if the floor plan allows for it.

 

[aw113sgte]

look close at your MTV truck. Note that portion of the transmission sites above the upper chassis rail. To clear the transmission you will need either a third chassis rail.... or put a dog house in you box to hump over it; if the floor plan allows for it.

Yep, got that all measured out. I may get a laser scanner and do the whole truck so I can have accurate dimensions for the CAD work. Plan on fully designing it on the computer as that's what I do for my work.
If I do that, I'll make sure to make the files available.

 

[Ronmar]

Yep, got that all measured out. I may get a laser scanner and do the whole truck so I can have accurate dimensions for the CAD work. Plan on fully designing it on the computer as that's what I do for my work.
If I do that, I'll make sure to make the files available.

Scanning would be cool. It took a lot of time to get dimensions to get the cab and chassis into autocad. I usually get pretty good the 2nd or 3rd time I build something, so I try and get those first couple of builds out of the way in CAD

 

[Third From Texas]

I usually get pretty good the 2nd or 3rd time I build something

Yep, that's me.

Measure once, go to Home Depot three times"

 

[Lostchain]

When on the highway when maintaining 50-55 I have what sounds like gear lash noise. Goes away completely on accel/decel. Do these trucks tend to make some noise from the hub gears?

Sounds exactly like what my truck did. Pretty sure that is the completely normal sound of the gear reduction hubs. Mine did it more or less any time I was holding a set speed above 40, but adding/removing throttle quieted it up. Gear lash was exactly how I thought of it. I rode in another LMTV that did it and also have seen YouTube videos where I can hear it. My hubs had a recent service date and were flawless inside when I changed over to the ECO Hubs. The sound is completely gone now so it was 100% the reduction making the noise.

 

[ckouba]

My hubs had a recent service date and were flawless inside when I changed over to the ECO Hubs. The sound is completely gone now so it was 100% the reduction making the noise.

Exactly my experience as well. I was worried I had a diff that needed to be shimmed or something along those lines. It was all in the bevel geared hubs.

 

[Ronmar]

I forgot to ask, have you run temps on the hubs? an overly warm hub might indicate an internal issue…

 

[Wingnut13]

Exactly my experience as well. I was worried I had a diff that needed to be shimmed or something along those lines. It was all in the bevel geared hubs.

This is exactly what I was worried about. I was trying to check pinion lash etc. great to know.