Speedometer Gear Part Number

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rodrju

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Hello:

Just got done working with a friend on a 7 1/4 —> 8 1/4 police 2.94 posi swap on the 85 Diplomat. Car has the original 318 with 904/999 transmission.

I am trying to locate the correct all-plastic 29 tooth speedometer gear. It has been elusive.

Does anyone have a Chrysler part number or a good source for this item?


Thanks in advance.
 
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I spoke with Dan at Brewers this AM. He was not hopeful that gear would be in stock anytime soon.

I am hoping to find the original Chrysler part number to see if I can locate one.

I was avoiding having to convert it.
 
rodrju said:
I spoke with Dan at Brewers this AM. He was not hopeful that gear would be in stock anytime soon.

I am hoping to find the original Chrysler part number to see if I can locate one.

I was avoiding having to convert it.
Click to expand...

The Chrysler part number for the speedometer pinion gear with 29 teeth (black) for 1985, and others, is 4058129.
 
WOW!

Talked to Leon at Silke’s—
Got the gear ordered using the part number provided. This is super helpful and is going to save me from having to swap the speedometer cable/housing.

Much thanks to everyone that responded!!!

It is really appreciated and hopefully helpful to someone in the future.
 
Glad you Got the gear you need. I have Bought things from Leon before as well. Good guy with good stuff for our cars and vans!
 
Leon was very helpful. Even called me up to tell me the order shipped and thank me for the business. Definitely knows he’s parts/inventory.
Highly recommended.

Brewers Performance in Ohio and A&A Transmission in Indiana were also very helpful.
 
So now…what is the best method to remove the speedometer cable?

It is not the old style with a hex fitting on the end.

It’s it clipped or push in?

I see that the speedo gear housing still has a retaining bolt…but what removes the cable?

Thanks
 
rodrju said:
So now…what is the best method to remove the speedometer cable?

It is not the old style with a hex fitting on the end.

It’s it clipped or push in?

I see that the speedo gear housing still has a retaining bolt…but what removes the cable?

Thanks
Click to expand...

Remove the speedometer gear housing bolt and retainer to release the speedometer gear housing. Watch for fluid spillage.
The pinion gear is retained to the housing/cable with a clip and the housing, or adapter, itself is retained to the cable with another clip as shown in the following image:
Screenshot 2025-08-25 11.55.09 AM.png
 
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Vaanth said:
Remove the speedometer gear housing bolt and retainer to release the speedometer gear housing. Watch for fluid spillage.
The pinion gear is retained to the housing/cable with a clip and the housing, or adapter, itself is retained to the cable with another clip as shown in the following image:
View attachment 56681
Click to expand...
What he said!
 
I have had issues in the past with the plastic housing getting stuck so it may not pop right out after removing the bolt and retainer.
 
Was able to get the 29 tooth gear installed—very straightforward process. One bolt, a little fluid mess. 20 minutes.

Speed is much more accurate now and so far no leaks.

Thanks for the explanation and diagram. Very helpful.

I am still have the cruise control unit on the car—but it is no longer operational after the intake/carb swap.

I may look to remove it in the future and go to a single speedometer cable setup.

I would assume most of the cop cars were not equipped with cruise—hopefully the cable is still be available.

So many members on this forum have been immensely helpful.
Thank you all!!
 
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