Need to re-gear the speed-o

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    Author Topic: Need to re-gear the speed-o  (Read 3425 times)

    Offline widing'cuda

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    • 70 'cuda383 - BS23N0E
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    Need to re-gear the speed-o
    « on: February 18, 2007 - 08:37:36 AM »
    I have a 70 'Cuda with 727 3.23 rear gear.What teeth size speedometer gear should I use?
    My rear tire are 275/60-15 (Tire Diameter 28.00 inch). But I'm getting 255/60-15 (Tire Diameter  27.00 inch).
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    - Jørgen - Norwegian Mopar fanatic

    1970 Plymouth 'Cuda 383 A833 8-3/4 3.23 suregrip
    http://cuda.widing.biz/


    Offline MEK-Dangerfield

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    Re: Need to re-gear the speed-o
    « Reply #1 on: February 18, 2007 - 08:50:13 AM »
    I can narrow it down a little. I have the same tire size on my rear, but I thought they were 26".  :clueless: In any event, I went with 34 teeth, and it is dead on.


       Mike
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    Mike

    1970 Challenger - SOLD
    2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

    Offline tactransman

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    Re: Need to re-gear the speed-o
    « Reply #2 on: February 18, 2007 - 09:01:41 AM »
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    Terry-tactransman 
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    Offline MEK-Dangerfield

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    Re: Need to re-gear the speed-o
    « Reply #3 on: February 18, 2007 - 09:17:10 AM »
    Quote from: tactransman on February 18, 2007 - 09:01:41 AM
    Take a look at this link :thumbsup:
    http://www.moparts.com/Tech/tech/pages/speedo.html


    See, that's where I get confused. That chart says 33 teeth BUT it's for a 3:21 rear. Who here has a 3:21 rear?  :screwy: 33 teeth had me 4-5 MPH too fast, so 34 did the trick. Sorry to vent.  :-[


       Mike
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    Mike

    1970 Challenger - SOLD
    2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

    Offline Bullitt-

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    Re: Need to re-gear the speed-o
    « Reply #4 on: February 18, 2007 - 09:41:48 AM »
    calculator I found .. 255/60/15 tire & 3.23 gear gives 31.31 teeth, 31 teeth pinion = part # 52068153(green)

    http://www.moparts.com/Tech/tech/img/AUTOMATICchart.xls

    Teeth Color Part Number
    27 (white) 52068149
    28 (blue)  52068150
    29 (black) 52068151
    30 (yellow)  52068152
    31 (green)  52068153
    32 (black) 52068154
    33 (yellow) 52068155
    34 (green) 52068156
    35 (orange)  52068157
    36 (red) 52068158
    37 (white)  52068159
    38 (blue) 52068060
    39 (green) 52068061
    40 (orange)  52068062
    « Last Edit: February 18, 2007 - 09:48:55 AM by bullitt99 »
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    Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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    Offline 70challengerrt

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    Re: Need to re-gear the speed-o
    « Reply #5 on: February 18, 2007 - 10:04:40 AM »
    Year one has a chart that matchs tire size to rear end gearing. According to the chart you need 33 tooth gear (yellow gear) year one part #FD033. I went off the tires you are going to run 255/60 R15.
    Todd
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    Offline widing'cuda

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    Re: Need to re-gear the speed-o
    « Reply #6 on: February 18, 2007 - 01:45:01 PM »
    Thanks guys I'll get myself a 33 and 34 and see what turns out the best. Is it easy to swap them. Never done this before.  Will I loose lots of transmission oil?
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    - Jørgen - Norwegian Mopar fanatic

    1970 Plymouth 'Cuda 383 A833 8-3/4 3.23 suregrip
    http://cuda.widing.biz/

    Offline tactransman

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    Re: Need to re-gear the speed-o
    « Reply #7 on: February 18, 2007 - 02:04:31 PM »
    Jack the back of the car way up,all the fluid will go to the front,piece of cake. Make sure you "index" the speedo bullit correctly. Speedo gear number group goes down.
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    Terry-tactransman 
    Torqueflite/Automatic Transmission Specialist
    Union, Mo.
    Give a man a fish and he eats for a day,teach him to fish and he eats for a lifetime.

    Offline widing'cuda

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    Re: Need to re-gear the speed-o
    « Reply #8 on: February 18, 2007 - 02:50:53 PM »
    Quote from: tactransman on February 18, 2007 - 02:04:31 PM
    Jack the back of the car way up,all the fluid will go to the front,piece of cake. Make sure you "index" the speedo bullit correctly. Speedo gear number group goes down.

    How do I do that?
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    - Jørgen - Norwegian Mopar fanatic

    1970 Plymouth 'Cuda 383 A833 8-3/4 3.23 suregrip
    http://cuda.widing.biz/

    Offline MEK-Dangerfield

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    Re: Need to re-gear the speed-o
    « Reply #9 on: February 18, 2007 - 03:28:50 PM »
    Quote from: widing'cuda on February 18, 2007 - 02:50:53 PM
    How do I do that?

    Good question. When i bought my car, it had a 26 tooth gear in it. I was reading 90 at 60 MPH.  :dupe: You might notice outside the gear housing, there are numbers for gear ranges. The range gear you want(33,34) needs to be at the bottom. I didn't tilt my car, and probably lost almost a quart of tranny fluid when I did the swap. Have a pan ready.  :thumbsup: Believe it or not, tranny fluid stinks.  :eek4:


      Mike
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    Mike

    1970 Challenger - SOLD
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    Offline inot2old

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    Re: Need to re-gear the speed-o
    « Reply #10 on: February 18, 2007 - 07:35:55 PM »
    I need to do that too.  My speedo shows about 80 at 60.  I know somebody has changed the gearing in my car but didn't change the speedo gear. :stomp:
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    Offline widing'cuda

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    Re: Need to re-gear the speed-o
    « Reply #11 on: February 19, 2007 - 10:43:54 AM »
    Quote from: MEKrunner on February 18, 2007 - 03:28:50 PM
    Good question. When i bought my car, it had a 26 tooth gear in it. I was reading 90 at 60 MPH.  :dupe: You might notice outside the gear housing, there are numbers for gear ranges. The range gear you want(33,34) needs to be at the bottom. I didn't tilt my car, and probably lost almost a quart of tranny fluid when I did the swap. Have a pan ready.  :thumbsup: Believe it or not, tranny fluid stinks.

    Ok... I think I get it. Min is showing 90 mph in 60 mph as well. I won't do it before in the spring time (April/May).
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    - Jørgen - Norwegian Mopar fanatic

    1970 Plymouth 'Cuda 383 A833 8-3/4 3.23 suregrip
    http://cuda.widing.biz/

    Offline heminut

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    Re: Need to re-gear the speed-o
    « Reply #12 on: February 20, 2007 - 08:20:18 AM »
    Quote from: MEKrunner on February 18, 2007 - 03:28:50 PM
    I didn't tilt my car, and probably lost almost a quart of tranny fluid when I did the swap. Have a pan ready.  :thumbsup: Believe it or not, tranny fluid stinks.  :eek4:


      Mike

    It also doesn't wash out of white T-shirts either!!! :scared:  :roflsmiley:
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    1970 5.7 Hemi Cuda
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