M1078 LMTV planetary hub setup

[steve6x6x6]

Working with the FMTV hub it is very important to setup up the clearance of these gears after removing the hub and reinstall. When the bearings are replaced of cleaned and repacked you need to check the gear clearance. I use a tool to check the clearance of these gears, this clamps it down so you do not get a false reading. . Min. .010 to .020

 

[Suprman]

Interesting. I was curious about the theory behind the planetary hubs. Everyone looks at the axles and says how small they look compared to the older trucks' axles.

 

[OktobrVega]

Hard to use the Armys new method without the 1500.00 tool they get to use but maybe this gives some ideas.


https://www.youtube.com/watch?v=QS6Wx915Wks




Heres the PS magazine mentioned in video. Page 14-15

http://psmag.radionerds.com/images/7/70/PS_Magazine_Issue_696_November_2010.pdf



TM
http://trucks25tonm1078v1-5.tpub.com/TM-9-2320-365-20-3/css/TM-9-2320-365-20-3_726.htm

 

[NDT]

How have you been setting up the required 2.1705 +-.0025 clearance between the shim and the face of the wheel end hub? What retailer has shims?

 

[steve6x6x6]

I have torn down quite a few of these brand new LMTV front axles to find that there really is not much of any torque on the spindle nut against the wheel bearings. This is the start of where the spindle nut is set to do the rest of your setup.

 

[steve6x6x6]

How have you been setting up the required 2.1705 +-.0025 clearance between the shim and the face of the wheel end hub? What retailer has shims?

The shims come in .015, .020, but most of them are .025. Working with new fronts makes it easy. The other side of the planetary is all ready done. As for the 2.1705 + -, i will thrust my clearance way of setup over the engineered way. Is everyone that has a M1078 and up going to out to find one of these tools?

 

[tennmogger]

The shims come in .015, .020, but most of them are .025. Working with new fronts makes it easy. The other side of the planetary is all ready done. As for the 2.1705 + -, i will thrust my clearance way of setup over the engineered way. Is everyone that has a M1078 and up going to out to find one of these tools?

Steve, please tell us more about your 'clearance way' of setting the shim thickness. I agree there is something vague, or downright wrong, about assuming the spider pack is 2.1705" thick. They call that thickness "the mean of the hub variance measurement".

All the measurements are moot if the spiders are worn a little (as they will always be). How can the tolerance be set to 0.005 accuracy if the ACTUAL thickness of the spider assembly is not known?

There should be a better way. Seems the amount of play in the spiders would be a good prediction as to freeplay on the assembly (as set by the shims). That would be difficult to define subjectively (probably why it's not used), but any actual measurement or response check is better than assuming the spider thickness is 2.1705. Maybe it was when new, but our trucks are not new.

Bob

 

[coachgeo]

.....Bob

Hey Bob... little off topic but.... you got a PM.

Interesting that we are brothers again

 

[rchalmers3]

Steve, please tell us more about your 'clearance way' of setting the shim thickness.

From the first post, it appears he (Steve) has created a tool that he uses to measure the assembled clearance, using a feeler gauge! It looks very straight forward to me and I appreciate the ingenuity vs spending $1500 for a tool that has a single purpose!

I'll bet that tool will have marketable value when more of these trucks hit the road!

Rick

 

[scottmandu]

Interesting. I was curious about the theory behind the planetary hubs. Everyone looks at the axles and says how small they look compared to the older trucks' axles.

When torque multiplication is done at the wheels, components upstream of the reduction hubs can be smaller and less robust as they don't have to deal with the torque.

 

[coachgeo]

for archive purposes, here is text from PS magazine mentioned in video posted earlier

... The current FMTV wheel end hub adjustment procedure in our manuals is hard to do correctly. This procedure sets the play for your wheel end spider gear. The TM calls for a measurement from the hub face to the wheel nut with only a 0.005-in variance. Soldiers in the field must use a depth micrometer to correctly take and calculate the wheel end’s shim thickness. Failing to shim the wheel hub correctly could result in premature hub and bearing failure, so you want to get this right. Troops have come up with different measurements, some even as far out as 0.030 of an inch! Then one smart Soldier, with the help of a local machine shop, designed a tool that takes the micrometer reading and the math out of this procedure. The new tool consists of a digital dial indicator and a tool rest bench. The tool rest bench is machine ground to the mean of the hub variance measurement. While on the rest, zero the dial, then align the tool on the hub face. The measurement on the indicator is the amount of shims required. This tool-while on the rest-can also be used to measure the shims for proper thickness. Using this tool results in a quicker, more accurate procedure that requires less double checking by supervisors and is less confusing to users. This tool is difficult to make, so we recommend units purchase it directly from the manufacturer: Debolt Machine, Inc.

The boxed and ready-touse digital dial indicator and tool rest bench together cost about $1,012. The tool is stored in a wooden container and it comes with operating instructions. Tom Tarrell FMTV Equipment Specialist TACOM LCMC, Warren, MI

Paul Debolt 4208
West Pike Zanesville, OH
43701

Email: debolt(AT)columbus.rr(DOT)com Remove (capital letters), insert associated net syntax
Phone: 740-4FIVE4-808TWO

 

[Lmtv772]

Here isOktobrVega's post where he mentions the Magazine and video again, in case you missed it.
I mean for archive purposes

Hard to use the Armys new method without the 1500.00 tool they get to use but maybe this gives some ideas.


https://www.youtube.com/watch?v=QS6Wx915Wks




Heres the PS magazine mentioned in video. Page 14-15

http://psmag.radionerds.com/images/7/70/PS_Magazine_Issue_696_November_2010.pdf



TM
http://trucks25tonm1078v1-5.tpub.com/TM-9-2320-365-20-3/css/TM-9-2320-365-20-3_726.htm

 

[coachgeo]

Here isOktobrVega's post where he mentions the Magazine and video again, in case you missed it.
I mean for archive purposes

No didn't miss it. Geez sorry for being sooo stupid to think the site holding the psmag data might eventually go away someday. Thanks for pointing out my stupidity

 

[agazza2]

Steve6x6x6 have you ever heard of one of the front axles on the M-1078 being a little noisy around 20-30 mph like a regular differential that has backlash problems or wear? Is this a common issue on the FMTVs? The guy that bought the one I now have drove it from Ft Bragg to Arizona after changing all fluids. The pumpkin & planetary fluids look great, but planetary's may be to full.

By what I read, they should be filled in the 4 o'clock position. I am thinking of draining out the excess. Also front right tire is wearing unusual. Any suggestions or what you might have seen in the past would be helpful.

 

[TNriverjet]

I'm going to have to take my noisy driver's side front apart to check and wondered if we could collectively get two items archived for future reference.

1. Steve6x6x6, can you loan out or have more of the hub clearance tools made for sale?
2. We need a definitive source for the shims with part numbers. (I don't think this was logged in the earlier posts even though the shim thickness was named)

Thank you!

 

[f8617]

...source for the shims with part numbers...

Shim Kit 4715 (Meritor), NSN 5365-01-390-8484, PNs: 2203J9500=0.012inches, ****K9501=0.015in, L9502=0.02in, M9503=0.025in, N9504=0.03in
Source: Oshkosh Eqmnt

Strong recommendation: Cleaning & resealing the hub is a hassle, so purchase & replace:
the two CTIS seals pn A-1205-Q-2435,
two (brittle/broken) plastic CTIS seal guides NSN 5330-01-362-4993, pn 2297R6648,
four spider o-rings NSN 5331-01-392-1637 (per wheel/side).

 

[agazza2]

CTIS parts

Shim Kit 4715 (Meritor), NSN 5365-01-390-8484, PNs: 2203J9500=0.012inches, ****K9501=0.015in, L9502=0.02in, M9503=0.025in, N9504=0.03in
Source: Oshkosh Eqmnt

Strong recommendation: Cleaning & resealing the hub is a hassle, so purchase & replace:
the two CTIS seals pn A-1205-Q-2435,
two (brittle/broken) plastic CTIS seal guides NSN 5330-01-362-4993, pn 2297R6648,
four spider o-rings NSN 5331-01-392-1637 (per wheel/side).

Do you have a good source to purchase all these items from?

 

[f8617]

Do you have a good source to purchase all these items from?

SS vendors, ebay, meritorpartsonline.

 

[tennmogger]

Another source: finditparts.com just search on kit4715, contains 1 each of the above listed shims, about 7 bucks each kit, need 4 possibly.

 

[coachgeo]

Steve6x6x6 tells me the tool is to compress the 4 rubber O rings. I wonder then if this could then be a piece of wood with a sheet metal face that goes against the O-Ring Side??? Or flat plate on both sides so not to compress the "hard" wood between?