M1123 Shifter Problems

Archangel_Hk · 2025-05-16T06:49:26-0400

Morning Boys,

So I got in my HMMWV yesterday morning at the ass crack of dawn, fired it up, put it in gear and took off. It slid into gear as smooth as it should. Drove 40 miles to work and when I got there, I went to put it into reverse, the shift lever was harder to move. It went into gear just fine, just stiff shifter. When I left work 12 hours later, it was back to normal. Then I get home 40 miles later and the shift lever was stiff again. Any help would be greatly appreciated.

HoveringHMMWV · 2025-05-16T07:17:01-0400

Fluid level check ok?

Archangel_Hk · 2025-05-16T08:18:17-0400

HoveringHMMWV said:
Fluid level check ok?

Yeah, all the fluid is at the right levels and amazingly, all look clean.

Mogman · 2025-05-16T08:45:13-0400

Archangel_Hk said:
Yeah, all the fluid is at the right levels and amazingly, all look clean.

Look clean? you mean you have not changed all the fluids and filters?

Archangel_Hk · 2025-05-16T10:01:25-0400

Mogman said:
Look clean? you mean you have not changed all the fluids and filters?

That was the first trip. Engine oil, hub oil, trans fluid.

Mogman · 2025-05-16T10:09:47-0400

40 miles with unknown fluids?

Archangel_Hk · 2025-05-16T12:35:03-0400

Mogman said:
40 miles with unknown fluids?

Negative. That was after the initial fluid change. Had the vehicle delivered didn't want to drive it before all that was accomplished

Retiredwarhorses · 2025-05-16T12:47:48-0400

Fluids have nothing do with a shifter assy and hard shifting…unless something is restricting the shaft, I’d be looking at the shift linkage or the shifter I’ve replaced quite a few gummed up shifters.

DREDnot · 2025-05-16T15:35:41-0400

Yeah almost as important as the fluid changes is removing the shifter assembly completely and emptying that bag full of dirt that surrounds it. Never seen one that wasnt nastier than a shopvac.

While its out on your bench you should be able to find the reason for your problem.

If you are going to be installing reverse lights this would be the time to install the reverse light switch.

After alot of detailed cleaning and light lube where appropriate you should be able to reinstall a perfectly smooth shifter.

Archangel_Hk · 2025-05-16T16:36:57-0400

Retiredwarhorses said:
Fluids have nothing do with a shifter assy and hard shifting…unless something is restricting the shaft, I’d be looking at the shift linkage or the shifter I’ve replaced quite a few gummed up shifters.

That's what I was thinking. It still goes into gear properly, but the shift lever gets stiff after a while.

Archangel_Hk · 2025-05-17T10:52:48-0400

DREDnot said:
Yeah almost as important as the fluid changes is removing the shifter assembly completely and emptying that bag full of dirt that surrounds it. Never seen one that wasnt nastier than a shopvac.

While its out on your bench you should be able to find the reason for your problem.

If you are going to be installing reverse lights this would be the time to install the reverse light switch.

After alot of detailed cleaning and light lube where appropriate you should be able to reinstall a perfectly smooth shifter.

View attachment 946755

Looks like it's going to the shop. Unsure how to do that exactly. Don't want to jack it up. Unless you have some pointers.

M1123 Shifter Problems

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