Humvee Starter / Flexplate Teeth

[jake20]

Sigh... I think I'll have to change my flexplate to finally button up this topic. Had an event yesterday where I tried to start and heard the dreaded grinding sound. The bendix tried to engage into a spot on the flexplate that was already somewhat chewed up, couldn't grab it properly the first time, and chewed it up some more. So now I'm driving around with a 1" wrench to move the crankshaft manually as a backup

In other news, the HPG start switch is perfect and the exact model it should be. I've had it in for over 5 days and it's working exactly as it should be, perfect voltages, perfect movement, no stuck engagement, etc. I'll write another post at some point soon that aggregates/streamlines everything I've learned about these pesky switches, hopefully I can save some others from this hassle lol.

So far on my shopping list are:

- New flexplate
- New flexplate bolts (they're cheap enough)
- Transmission jack

Any tips on dropping the transmission would be appreciated

 

[Mogman]

Is the face of the flex plate teeth flattened out enough to interfere with the bendix engagement? That is what I would suspect, a little work with a small triangle file might do the trick, it does not look like that much tooth missing, not ideal or pretty but much less work.

 

[87cr250r]

Is the face of the flex plate teeth flattened out enough to interfere with the bendix engagement? That is what I would suspect, a little work with a small triangle file might do the trick, it does not look like that much tooth missing, not ideal or pretty but much less work.

Yes, the Bendix fully engages the flexplate tooth before connecting power to the starter. The damage in the picture will not cause the Bendix to slip.

 

[BJL21]

My flex plate is shot. So is my starter. It got chewed up to the point it won’t even catch. It’s just gouged now. I took the shim out hoping that might at least catch it one last time but, no. It didn’t. How hard is it to replace? Do I have to drop the tranny completely? Thanks in advance.

 

[jake20]

My flex plate is shot. So is my starter. It got chewed up to the point it won’t even catch. It’s just gouged now. I took the shim out hoping that might at least catch it one last time but, no. It didn’t. How hard is it to replace? Do I have to drop the tranny completely? Thanks in advance.

Yep, it’s not hard, just tedious. Get yourself a transmission jack AND regular jack. Trans jack on the pan, regular jack on the transfer case.

Basic idea is:
- unplug batteries so some hooligan doesn’t accidentally crank during this process
- put jack under t case
- remove cross bar support
- remove exhaust pipe that crosses under transmission
- disconnect cooler lines on frame rail
- disconnect vent lines from trans and t case (as you lower it)
- disconnect all wiring
- disconnect shift linkages
- unbolt rear driveshaft from diff and pull it out towards the rear from the t case
- unbolt the front driveshaft from t case and move it off to the side
- put trans jack under pan with light pressure
- unbolt bell housing bolts
- unbolt torque converter from flexplate, you’ll have to turn the crank a few times to get to each bolt, use a 1” wrench on crank pulley ribs
- slide trans assembly back and slowly lower it making sure nothing snags
- unbolt flex plate and put new one on, use RED loc tite for all the bolts, ensure you use the correct torque value
- reassemble it all

While you’re at it, change your torque converter seals/o-rings and rubber cooler lines as well. Call HPG and he’ll get you in the right direction with which seals to get.

Also, the flexplate bolts are supposed to be replaced, HPG also has them for a few cents each.

 

[Mogman]

Yep, it’s not hard, just tedious. Get yourself a transmission jack AND regular jack. Trans jack on the pan, regular jack on the transfer case.

Basic idea is:
- unplug batteries so some hooligan doesn’t accidentally crank during this process
- put jack under t case
- remove cross bar support
- remove exhaust pipe that crosses under transmission
- disconnect cooler lines on frame rail
- disconnect vent lines from trans and t case (as you lower it)
- disconnect all wiring
- disconnect shift linkages
- unbolt rear driveshaft from diff and pull it out towards the rear from the t case
- unbolt the front driveshaft from t case and move it off to the side
- put trans jack under pan with light pressure
- unbolt bell housing bolts
- unbolt torque converter from flexplate, you’ll have to turn the crank a few times to get to each bolt, use a 1” wrench on crank pulley ribs
- slide trans assembly back and slowly lower it making sure nothing snags
- unbolt flex plate and put new one on, use RED loc tite for all the bolts, ensure you use the correct torque value
- reassemble it all

While you’re at it, change your torque converter seals/o-rings and rubber cooler lines as well. Call HPG and he’ll get you in the right direction with which seals to get.

Also, the flexplate bolts are supposed to be replaced, HPG also has them for a few cents each.

That is a great write-up, the only thing I can think of to add is to take a small pry bar and after removing the last converter bolt to gently pry the converter towards the transmission to make sure it is released from the pilot in the crankshaft so the converter comes back with the transmission, it should slide back a half inch or so.
And of course do not lean the transmission/T case forward as the converter will slip off.

 

[jake20]

One more note, you may want a second person to operate and move the other jack around. A trans jack with a tilting top piece is great because you my have to tilt the assembly left while it comes down, due to how the transfer case sits near the fuel tank.