FMTV High Speed Gears

[Ohiobenz]

Someone please educate me....

When swapping the front diff, why do we not just remove the upper and lower pivots. #18 & 24. This would leave the whole hub gear assembly intact. Or am I missing something?

 

[Suprman]

I have heard taking the whole assembly off of the king pins is alot more work.

 

[Socommfg]

A LOT more work! Hard and Heavy. Pulling the axles and knuckles are the easiest way. Figure 2 to 3 days, to do the swap and have help, before you start.

 

[m-35tom]

Why would anybody want to have gearsets made or install takeouts when brand new Meritor gearsets can be installed by MTP Drivetrain for $1750 per axle?

Just to be clear this price is if you ship your diff to MTP for them to install the R & P into. You still need to take your truck apart yourself, this is not the price of them doing the whole truck which is $5575 for 2 axles. The diffs I sell are NEW so bearings and pinion seal are new, it is almost a equal price plus your truck is not down for a month, plus you then have spare diffs to do something with later.

 

[DiverDarrell]

Having done the swap, you want to to do the take the hub apart method. The weights of the parts involved are high. Additionally the inside wheel bearing should be serviced every so often. On the fronts I found the hardest part was getting the axle shafts re-installed. Getting the splines lined up was a pain. Took me by myself two full days to do the swap, but had already prepped the rear with a locker, and had a transmission Jack and a forklift to help. Also I was able to properly shim the hub gerars, making for a much quieter ride.

 

[m-35tom]

Another BIG reason to do it the take apart way is that your hubs will likely be full of chewed up silicone and also need the lash set. Those army monkeys think a whole tube of silicone for each side is the amount to use!! I have a forklift so dealing with the tires should be painless.

 

[Ohiobenz]

My M1079 has a whopping 3700 miles on it.... and is a very clean, rust free example of an LMTV...
How pressing is the need to replace seals??

 

[m-35tom]

How do you know it only has 3700 miles on it? It may have gone through at least one rebuild where they did not do the seals or is that something that is done each time? You may not have to, but I have seen many things taken apart and put back that the seals then developed leaks. I would take it apart carefully, clean everything and with lube on the seals put it back. You may be OK. My truck is a 94 with unknown miles so I will replace them. (My truck shows 1700 but is obviously much more than that)

 

[Ohiobenz]

How do you know it only has 3700 miles on it? It may have gone through at least one rebuild where they did not do the seals or is that something that is done each time? You may not have to, but I have seen many things taken apart and put back that the seals then developed leaks. I would take it apart carefully, clean everything and with lube on the seals put it back. You may be OK. My truck is a 94 with unknown miles so I will replace them. (My truck shows 1700 but is obviously much more than that)

I guess you'd have to see the truck. I've stripped the cab down completely inside for one thing and there is/was minimal wear on any areas where you would expect to see it. No accumulation of dirt etc under the instrument panel or under the fuse box. Everything in the engine area looks typical of a used low mileage vehicle.
The worst I found was some galvanic action at the spot welds on the floor.
The engine holds a nice 60-80psi oil pressure at idle, the oil looked relatively clean when I changed it. I see no sign of any excess gasketmaker goop anywhere. I've worked on a lot of cars for the past 50yrs, but I could be wrong...

 

[DiverDarrell]

Well it's 3700 miles on that odometer, I trust them about as much as you can trust a military vehicle fuel guage. If that's the case my lmtv is under 500 miles on the odometer 94 vintage with no rust. Guestimate mine has around 30k on it actually. My odometer guage and a couple others look newer. And if yours is true miles than how long ago we're the bearings serviced? How old is the grease that's in there. How long did it sit still. Worst thing for seals is to have them sit. I doubt the seals are bad, but cleaning and re greasing the inner bearings is cheap insurance. And the hubs... Well they are not easy to set the lash, and knowing a few mechanic s they told me to steer away from the lmtv because of the hubs. The army method for setting lash is at best a guesstimate. And as stated they use an entire tube of rtv to put it back together.

Pulling hubs is easy,. With the tool setting lash is easy,. Putting synthetic oil in the hubs will have them run cooler, and grease is cheap. Until you look for yourself at the condition of the hubs, bearings and seals, you don't know if the last 18yo private who can only think about beer o clock and who could give no craps and does the bare min to get by, did the job correct. In the long run I think pulling the king pins will be more difficult and with all the weight, exposes risk to damaging machined surface.


But hey, it's your truck!! Your adventure!!! Opinions are free after all. I'm all for you trying it out and telling us how it went, with lots of photos showing the process. You will have the hub, brake assemy, knuckle and drive axle out as one large assembly. It could turn out to be the best way to do it.

Too bad your truck is so clean inside ,. I found some live ammo in mine, hidden under a few pounds of sand. Sounds like you have a sweet truck, and the high-speed gears are worth every penny, however they are installed.

 

[Ohiobenz]

I'm quite happy with my clean truck lol.
But there's no doubt that 18yo motorpool kids work on these... and I do realize a clean and repair/replace is the best preventative option.

 

[Chism]

Did we ever determine if a ring and pinion can be swapped in the original chuck? I have a contact at a gear manufacture that is willing to make custom sets..

Can your gear manufacturer connection make a torque biasing, or torque-sensing (“Torsen”) differential for these axles?


Sent from my iPhone using Tapatalk

 

[Rwood83]

Joe Goodnuff has 2.87:1 third members on the Facebook lmtv page.

 

[coachgeo]

surprised it took almost three days before that info made its way over to here.

 

[steve6x6x6]

Yea, $1,975.00 ea. and will need to be totally cleaned and all of the bearings replaced. I am not selling this junk, somebody else listing.

 

[Rwood83]

This is a different guy. He is offering rebuilt third members for $2200 each. He is out of Oregon.

 

[tennmogger]

What are the 2.87:1 diffs out of?

 

[wheelspinner]

I'll be honest, the 3:07 sure puts my truck right where it feels like it wants to be. I have towed about 9-10,000 lbs and another 2k in the bed and its doing pretty well. I think in my duty cycle ( I don't want to go 75 mph) and towing some weight I would not like the performance at all with any numerically lower gears. And I have the 290hp in an LMTV. I guess if its nothing but a parade queen or coffee fetcher it might be ok, but I'm pretty sure this ratio would not be for me.

 

[Rwood83]

I think he sourced the ring and pinions. He is offering rebuilt third members on a exchange basis.

 

[coachgeo]

What are the 2.87:1 diffs out of?

I believe he convinced Meritor to make a batch.... or he bought a rusty one like Steve Showed and then sent the gears off to a known gear making corp. to make a 100 sets. Aka..... they are not out of anything..... they are brand spanking new.

I suspect he wants to do the build in each third for warranty purposes..... aka..... if he builds; then he knows each pumpkin is built to spec. If a person does it themselves; he has no clue if the pumpkin was assembled to spec. with new parts etc.. and if something goes wrong cause of poor assembly by one of the self assemblers..... wisdom points out in today's social media world, if that person decides the R&P was faulty and not their poor build they did, then there is a possibility they will jump on the net and trash his good name ...... which can kill a business before it is solidly off the ground. Suspect this is same reason why the guy in LA doing builds with 3.07's will only do them in his shop as well.