M998 Speedometer repair

[dcartledge]

OK - my speedo quit working.

Checked the head - appears to be ok. Replaced the cable - the old one is seized.

Still doesn't work. So next step is to replace the gear and 90 degree adapter.

The question is does this gear simply drop into place or is it indexed somehow that makes a difference. I think it should just drop in since it is a freewheeling spinner.

Thanks for input,
d

[Augi]

It does matter how the housing that holds the gear is indexed. I don't know how to do it yet though, as I haven't installed my new t-case yet.

The TM probably tells all....


Augi

[Action]

I have an electric speedo, so this may not be exact.

There is a number on the plastic gear that drops into the transfer case. The fixture on the outside that holds this gear has four numbered spots around the outside edge. The transfer case has a mark by the edge of the hole. Line up the number of the housing that corresponds to the gear number with the mark on the case. Use a bolt to hold the "C" retainer around the fixture.

If your old cable got siezed and the transfer case kept trying to turn it, then that plastic gear could need repleced. I think they are under 10 bucks.

Jason

[dcartledge]

I have everything except the actual plastic worm gear that mounts on the shaft inside the transfer case - hope that isn't broken,
d

[dunsbr]

When my mechanical speedo died about 8 years ago due to the old cable binding up,the part that failed was the little square drive pin in the right angle drive.
They are designed to be a weak point to prevent cable failure.
They are also a cheap, commonly available part. Any cable maker will have them.

Cheers

[TheHummerguy]

I always start at the Tcase and work backwards to the Speedo, I start by undoing the cable at the 90degree adapter...put a cordless drill on the end of the
cable, and let her rip....it should read about 20mph, I think you have to put the drill in reverse if memory serves me correctly.
if that is ok...the issue is the 90 degree adapter....Never ever had the T-case as the issue. But i do have one of those gears for the T-case.

[dcartledge]

Thanks for advice.

I'll let y'all know.
d

[actionpaintball]

I have replaced the worm drive gear, cable, and/or the 90 degree adapter. I have not seen any other failures personally.

The drive gears are all color coded depending on what ratio you need (tcase and trans ratio, plus tire size).

[dunsbr]

Hi Guys,

Here's a pic showing a speedometer drive pin to illustrate the bit I had break on my truck.


(Note: It's a general pic, not the actual humvee part.)

Cheers

[dcartledge]

The small piece was missing between the 90 degree adapter and the cable.

After installing it - appears to work now.

Thanks for the assistance everyone.
d

[Action]

The manual shows the pin below the 90 degree fitting, not at the front.

Jason

[dcartledge]

Still working - naturally I bought a couple spare drive gears and cable.

Oh well ....
d