Speedometer issue

Cybul · Apr 24, 2025

Hi.
I have a problem with the speedometer on my m1152a1.

What I have tested:
1. I unscrewed the tachometer generator (#12480922)
The plates were bent so I squeezed them.

2. I put the pin (Sender Tachometer Generator?) to the drill

3. The moment I switched on the drill, the pin started to rotate in the generator and the speedometer works.

It follows that the cable, speedometer and tachometer generator is ok.

However, the speedometer does not work when driving.
The sender most likely does not rotate, which means there is probably something faulty in the transfer case, maybe the socket that the sender goes into?
Any suggestions?

Mogman · Apr 24, 2025

It is most likely the plastic gears in the TC, or the gear is simply not clocked correctly.

Cybul · Apr 25, 2025

Mogman said:
It is most likely the plastic gears in the TC, or the gear is simply not clocked correctly.

So the only option is to disassemble the TC?

Mogman · Apr 25, 2025

Cybul said:
So the only option is to disassemble the TC?

No, you can start in TM 9-2320-280-20-2, 5-24. SPEEDOMETER DRIVEN GEAR MAINTENANCE and inspect if the gears are OK and if the gear is timed correctly.

Cybul · Apr 25, 2025

Mogman said:
No, you can start in TM 9-2320-280-20-2, 5-24. SPEEDOMETER DRIVEN GEAR MAINTENANCE and inspect if the gears are OK and if the gear is timed correctly.

This instruction is for the old type with line. My is electronic.
And in TM-9-2320-387-24-1 I have found:
5-17. SPEEDOMETER DRIVEN GEAR REPLACEMENT

Will check what is inside. Thx.

Mogman · Apr 25, 2025

Same information, all they did was replace the cable with a sending unit.

Cybul · May 11, 2025

Here is a reason:

I have found a new item in the shops but there is a considerable price disparity, from 15usd (hummerh1parts) to 65usd (ebay) (macmotors ~34usd). What is the reason for this? Is there any chance that the cheapest ones are not original?

Cybul · 2025-07-13T16:36:56-0400

Ok.
I have new part:

but there is also an issue inside the transfer case, the worm gear is also damaged:

Unfortunately I cannot find this component, does anyone know the number and is the gear itself available?
It will probably be impossible to repair it without disassembling whole transfer case?

Second question:

What is it about these numbers and how do I fit this correctly when assembling given that the hole is not in the middle?

Mogman · 2025-07-13T16:57:09-0400

The drive gear is the same for the TH-350, TH-400 3L60. 3L80 and 4L80 transmissions, obviously you want the blue one, you will have to remove the drive shaft and tail section off of the transfer case.
There is allot of information about timing the driven gear housing given the colors of the drive and driven gears, also I am sure it is in the maint TM.
Make sure you replace the cable or speedo depending on which one caused the issue.

Cybul · 2025-07-13T17:14:09-0400

The speedometer and wires are ok. Most likely someone put it together wrong before and the result is what it is.

Mogman · 2025-07-13T17:26:23-0400

Cybul said:
The speedometer and wires are ok. Most likely someone put it together wrong before and the result is what it is.
Something killed the gears, the sending unit or the right angle gear box (if it had one) seized.
It is possible but less likely the driven gear was not timed but it looks like they were fully meshed when they failed, but still a possibility.

Speedometer issue

More options

Cybul

Member

Mogman

Moderator

Cybul

Member

Mogman

Moderator

Cybul

Member

Mogman

Moderator

Cybul

Member

Cybul

Member

Mogman

Moderator

Cybul

Member

Mogman

Moderator