Starter Drive Grinding Ring Gear

[nbkbjy1]

Good afternoon SS,

Relatively new to the forum and appreciate the tremendous resource SS provides for HMMWV related questions. A friend suggested I reach out to the community to help diagnose the cause and identify a solution to a grinding starter drive bendix and flex plate ring gear.

This 2005 M1123 with a professionally installed 6.5TD unexpectedly stopped starting. As luck would have it, it happened in a remote area that left us stranded for hours until a flatbed tow truck arrived. On the bright side, it happened after we completed the 2N47 Cleghorn Ridge trail among a group of trail rigs with helpful friends.

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Ultimately, what would esteemed and knowledgeable SS members do in this situation?
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Grinding "No-start" Video: https://youtu.be/4RcmrerJRmY

Background info:
2005 M1123 MAK reset chassis with 4L80e
6.5TD takeout motor from early 2000's M1113/M1114 professionally installed ~3months ago
Driven 1,550 miles since picked up (<100 starts)
24Volt Prestolite starter CAGE Code 0EDY1 (shim thickness TBD)
Starter bolts are tight with no play
Zero prior "no-starts" up until this failure (did emit a brief squeak/squeal)
Based on the video & images, bendix appears to fully extend, but fails to catch on the worn gear teeth


Current plan:
1. Replace with new flexplate/flywheel ring gear & bolts (NSN# 2815-01-148-3771)
2. Replace with new starter drive bendix (NSN# 2920-01-187-1310)

Questions:
1. Given that the 6.5TD was professionally installed roughly 3months/1,550 miles ago, what can cause the ring gear and bendix gear to get chewed up this quickly?
2. What tips, tricks, or pitfalls are involved when moving the transmission rearwards to install the new ring gear & bendix?
3. What special measurement devices or HMMWV specific tools (if any) are required to align the gear teeth contact?
4. Does the starter have to be completely removed and disassembled just to replace the bendix?
5. How does one diagnose other issues that would require a new replacement starter instead?
6. What mechanic is recommended (ideally in California) to successfully repair this issue?

 

[dilvoy]

Shim is .008 thick. make sure that the nose casting doesn't say something like "no shim". If so don't use a shim. Is the stud at the forward end of the starter properly held in place to the bracket with a nut?

 

[86humv]

As Dilvoy says....its at the motor mount.

 

[RustyM923]

Looks like an installation error. Maybe take it back to the professional that installed it (if recently installed)

 

[Retiredwarhorses]

Let me chime in here....I did the conversion.
the starter and all it’s components came on the motor. When a bendix fails, continued operation will chip teeth, as in this scenario. It’s a simple starter change out and flex plate replacement, all done pretty simply while in the truck, have done many. The OP contacted me and I sent him links to new, NOS and very nice takeout starters.
while the bendix can be changed out, the time it takes and experience to set the lash correctly on the bench is not always for the shade tree mechanic. I’ve done several bendix replacements, the labor hours to change it make no sense
to fix it, starters are quite plentiful IMO, I have a stack of them here in the shop.
As far as shims go, all HMMWV’s use the same shim, there are 2, never is 25yrs have I seen a starter without the thick shim. If it was wrong to start with, there would have been grinding sound at most if not all start ups.
i just had a truck in the shop that had a “Tinging noise while running” had been to multiple shops, 1 min under the truck revealed the bendix was “floating” outward on the shaft after startup and pinging off the flex plate.
Inspected all flex plate teeth for missing or damaged and starter was replaced...problem solved.

 

[Retiredwarhorses]

As Dilvoy says....its at the motor mount.

All late model A2 and Turbo motors have the “Hook style” front support....if I do a starter on an A0/A1’s truck, I Install the new style bracket, makes installing the starter a breeze compared to the old style.

 

[nbkbjy1]

@Dilvoy & @86humv - thanks for the input.

@Retiredwarhorses - appreciate the feedback about replacing both the flexplate & starter. With all the parts on hand, how many hours would it take to replace them?

 

[nbkbjy1]

@Dilvoy & @86humv - thanks for the input.
@Retiredwarhorses - appreciate the feedback about replacing both the flexplate & starter. With all the parts on hand, how many hours would it take to replace them?

 

[RustyM923]

I’m having similar problems (occasional grind) on mine. Looking forward to the final resolution on this one.

 

[Retiredwarhorses]

I’m having similar problems (occasional grind) on mine. Looking forward to the final resolution on this one.

Check the flex plate for missing teeth, if it just try’s to engage at times and won’t, “not grinding” that’s a bad bendix or weak solenoid, not enough power to shoot the bendix out far enough to engage the flex plate.
simplest solution is to just replace the starter...

 

[nbkbjy1]

@Retiredwarhorses - appreciate the feedback. With all the parts on hand, how many hours would it take to replace the flexplate & starter?

 

[RustyM923]

Check the flex plate for missing teeth, if it just try’s to engage at times and won’t, “not grinding” that’s a bad bendix or weak solenoid, not enough power to shoot the bendix out far enough to engage the flex plate.
simplest solution is to just replace the starter...

It looks like I have some flat teeth on a part of the flexplate. Ugh. I’ll definitely get a new starter, too.

As I can’t leave this overnight where I can work on it....
How long will it take to swap the flex plate?







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[Milcommoguy]

That's a tough question with MANY variables. Flex plate easy. Getting to it time consuming.

How fast can you spin wrenches? How many Red Bull's? How many honey do's in between?

Even with my NASCAR hat on it's a guessing game.

So with all the right parts on the bench?
Jacks on the floor?
Bolts not rusted / busted?
Everything coming apart with minimal swear words?
No blood shed?
No dirt / fluids in the eye's?
Additional technical or muscle helps shows up on time?
No additional problems found?
Fix the kids bike tire
Remove and replace flex plate, quick
And put it all back together
and test drive???

In my drive way give it a week, I work slow.

Not something that's going down it front of AutoZone. CAMO

 

[RustyM923]

That's a tough question with MANY variables. Flex plate easy. Getting to it time consuming.

How fast can you spin wrenches? How many Red Bull's? How many honey do's in between?

Even with my NASCAR hat on it's a guessing game.

So with all the right parts on the bench?
Jacks on the floor?
Bolts not rusted / busted?
Everything coming apart with minimal swear words?
No blood shed?
No dirt / fluids in the eye's?
Additional technical or muscle helps shows up on time?
No additional problems found?
Fix the kids bike tire
Remove and replace flex plate, quick
And put it all back together
and test drive???

In my drive way give it a week, I work slow.

Not something that's going down it front of AutoZone. CAMO

That’s all very helpful, thank you.

I’m still curious what a real Hmmwv mechanic (like retiredwarhorses) would charge to do this for me. No bike tires, no blood in the face etc. I just figured the people that work on them all the time might be able to chime in and tell me what a reasonable timeframe to get this done would be.

8 hours I’d imagine? Reasonable?




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[Retiredwarhorses]

@Retiredwarhorses - appreciate the feedback. With all the parts on hand, how many hours would it take to replace the flexplate & starter?

It’s easily 8hrs

the only shop in SoCal would be Tustin Hummer...

 

[Milcommoguy]

I am curious too. How is it that the affordable parts are always the hardest to get to. Since I work for free on only mine, flywheel cheap, labor $$$$ my guess. CAMO

https://www.easternsurplus.net/PartDetails/3267/HM-292-Flywheel-Assembly-HMMWV-CUCV-Diesel-engines and starter extra $$$$ never ends.

 

[RustyM923]

Sweet . I’m doing it Monday


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