speedometer gear

[shadango]

Gotcha! The pics are great!  So there should be a dot on the housing that lines up with one of the segmnets/lines....cool!

Do you think my math looks right?

I should have picked up the gears when I was at Carlise....they were EVERYWHERE! LOL

Just didnt know what one to get.

[MEK-Dangerfield]

At the risk of hi-jacking...My speedo gear housing has had slightly more than an ooze for years(a few drop per week). Is that O-ring available, or can I get away with using RTV on it as a quick fix?


  Mike

[tactransman]

Mike ,RTV is fine,just make sure everything is dry when it is applied.

[Pale Rider]

I don't see them on Mancini. What number of teeth do you need,I can look at the shop and see if I have one?

And do you have a 33 in the shop?

[Changin Gears]

Same issue here.....mind if I horn in a bit?

I read 30 when I am doing 35 (verified by gps)....that would be like 13% off!

Is that 2.5% figure correct for any number of teeth ?

Do you figure the percentage using the higher number or lower?

I used the higher number...35mph, and found that 30 mph is 14% lower than 35....divide by 2.5 and I get 5.6.... I need 5 or 6 fewer teeth, right?

I dont know what I have in there right now.....
does it just pull out of the tranny once you pull the speedo cable?

Going 35 but reads 5 mph slow - 5/35 = 14.28% off.  So you need a gear that will spin 14% faster.  A gear with 14% fewer teeth will do that.  As an example, if your current gear has 28 teeth you need a gear with 4 less teeth (28 x .1428 = 4).  But, if your current gear has 42 teeth you need a gear with 6 less teeth (42 x .1428 = 6).

Instead of testing at 35 mph I would test at 60 or 70 for better accuracy.

[Changin Gears]

The dealer may still have the one you are lookin for.  The original part numbers were 2538926 through 2538945 with the last 2 digits being the number of teeth.

[shadango]

Alright now I am officially cornfused.  LOL

I thought each tooth was worth 2.5%?

Is there a formula somewhere where you dump in tire size, rearend ratio and whatever else and out pops the answer?   

[Changin Gears]

Alright now I am officially cornfused.  LOL

I thought each tooth was worth 2.5%?

Is there a formula somewhere where you dump in tire size, rearend ratio and whatever else and out pops the answer?   

2.5% is good if you have a 40 tooth gear (1 tooth/ 40 teeth = 2.5%).

The equation I use for a non-testable vehicle is:

Number of Teeth = 259 * (axle ratio/tire diameter)

The method using the GPS is the best because is also calibrates your speedometer in your vehicle.

[shadango]

gotcha...and just saw the 60 mph hint....will do that soon.

Thanks for the help, and sorry to the OP for hijacking a bit!

[tactransman]

And do you have a 33 in the shop?

I have a black 32,that is as close as I get.

[MEK-Dangerfield]

For you guys with a console and slapstick, there is a bracket you need to remove to get to the speedo gear out. Nothing major here. Two nuts on the passenger's side of the tranny to take off. The first pic here is from the passenger's side.

shadango, I really think you need to know what gear you have in there before we start guessing. It took me three tries using that method.   

[shadango]

For you guys with a console and slapstick, there is a bracket you need to remove to get to the speedo gear out. Nothing major here. Two nuts on the passenger's side of the tranny to take off. The first pic here is from the passenger's side.

shadango, I really think you need to know what gear you have in there before we start guessing. It took me three tries using that method.   

yeah, no doubt.

I plan on pulling the gear first to see what I have in there.   

[CUDA JAS]

yeah, no doubt.

I plan on pulling the gear first to see what I have in there.   

Before you pull the gear to see what it is (other than wrong), try the spreadsheet at the link below (there is one for a auto or manual trans).  Plug in the numbers and see what gear you need.  Might save a step for you.

http://www.moparts.org/Tech/tech/pages/speedo.html

 

[shadango]

Before you pull the gear to see what it is (other than wrong), try the spreadsheet at the link below (there is one for a auto or manual trans).  Plug in the numbers and see what gear you need.  Might save a step for you.

http://www.moparts.org/Tech/tech/pages/speedo.html

Thats awesome!   Thanks!

[mopardave]

oe. Pinion number      tooth   current OE. number   Y/O number
2538930    yellow                   30   52068152 - NS1                 FD030
2538931   green                31   52068153 - NS1                 FD031
2538932   black                32   52068154                 FD032
2538933   yellow                33   52068155                 FD033
2538934   green                34   52068156                 FD034
2538935   orange                35   J3212735                              FD035
2538936   red                36   52068158                 FD036
2538937   white                37   52068159                 FD037
2538938   blue                38   52068060                 FD038
2538939   green                39   52068061                 FD039
2538940   orange                40   52068062                 FD040
2538941   red                41   2538941                              FD041
2538942   white                42   2538942                              FD042
2538943   blue                43   2538943                              FD043

Check with your local dealers, these are still available, the RED gear is the expensive ine the rest are about 9 bucks. y/o charges avg 29.