Speedometer after changing rear diffs.
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- Sweptline.ORG Member
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- City: Calgary
- State: Foreign
- Location: calgary
Speedometer after changing rear diffs.
Anyone know how to re sync speedometer? Changed rear diffs from 391’ to 294’s.Think my Speedo is about 10-15 miles to slow.1967 Dodge D100. Got a feeling this might be a pain in the arse,lol.
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- Sweptline.ORG Member
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- City: Binghamton
- State: NY
Re: Speedometer after changing rear diffs.
With my 65 I went from 4:88 gears to 4:10 I was off by about the same. I used a gear reduction box from an old Chevrolet. It screwed between the transfer case and to speedometer cable. It is accurate now.
Late 65 w 200.
Factory LU-2 winch.
Updates: 205 transfer case,4.10 gears, disc brake Dana 60 front with lock out hubs
440 repower in the works
60 d100
383 with 727
4 wheel disc
3.73 geared rear
Factory LU-2 winch.
Updates: 205 transfer case,4.10 gears, disc brake Dana 60 front with lock out hubs
440 repower in the works
60 d100
383 with 727
4 wheel disc
3.73 geared rear
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- Sweptline.ORG Member
- Posts: 454
- Joined: Fri Jan 01, 2021 11:46 pm
- City: Binghamton
- State: NY
Re: Speedometer after changing rear diffs.
If your truck is an automatic it’s a mater of changing speedometer gears. They are easy to change but can be hard to find the gears.
Late 65 w 200.
Factory LU-2 winch.
Updates: 205 transfer case,4.10 gears, disc brake Dana 60 front with lock out hubs
440 repower in the works
60 d100
383 with 727
4 wheel disc
3.73 geared rear
Factory LU-2 winch.
Updates: 205 transfer case,4.10 gears, disc brake Dana 60 front with lock out hubs
440 repower in the works
60 d100
383 with 727
4 wheel disc
3.73 geared rear
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- Sweptline.ORG Pioneer
- Posts: 7366
- Joined: Wed Dec 31, 1969 6:00 pm
- Location: Walnut Creek, CA
Re: Speedometer after changing rear diffs.
You can also easily change gears on a std tranny. Step by step instructions are in the FSM.
- martincom
- Sweptline.ORG Member
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- Joined: Thu Jul 30, 2020 10:04 am
- City: Five Points
- State: AL
Re: Speedometer after changing rear diffs.
There are charts in the service manual that indicate the number of teeth the speedometer pinion should have fro a given rear axle ratio and tire size combination. There also charts and calculators online that will yield the same results. Speedometer pinions are available from places like Year One and Ebay.
1*1971 D100 318 A/T
1*1970 Charger R/T 440-6PK A/T
2*1969 Daytona Charger 440 A/T
1*1969 Coronet R/T awaiting restoration
1*1969 Torino Talladega awaiting restoration
1*1970 Charger R/T 440-6PK A/T
2*1969 Daytona Charger 440 A/T
1*1969 Coronet R/T awaiting restoration
1*1969 Torino Talladega awaiting restoration
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- Sweptline.ORG Member
- Posts: 8
- Joined: Tue Dec 25, 2018 1:40 pm
- City: Calgary
- State: Foreign
- Location: calgary
Re: Speedometer after changing rear diffs.
Thanks for the info.It’s a 4-speed,maybe that makes it easier.
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- Sweptline.ORG Member
- Posts: 8
- Joined: Tue Dec 25, 2018 1:40 pm
- City: Calgary
- State: Foreign
- Location: calgary
Re: Speedometer after changing rear diffs.
Hello PwrWgnDriver. This may seem like a stupid question,but what is the FSM?
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- Sweptline.ORG Pioneer
- Posts: 7366
- Joined: Wed Dec 31, 1969 6:00 pm
- Location: Walnut Creek, CA
Re: Speedometer after changing rear diffs.
Factory Service Manual
Reprints available from Bishko, better quality than new!
Reprints available from Bishko, better quality than new!
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- Sweptline.ORG Member
- Posts: 8
- Joined: Tue Dec 25, 2018 1:40 pm
- City: Calgary
- State: Foreign
- Location: calgary
Re: Speedometer after changing rear diffs.
Thanks,I'll check it out.
- martincom
- Sweptline.ORG Member
- Posts: 448
- Joined: Thu Jul 30, 2020 10:04 am
- City: Five Points
- State: AL
Re: Speedometer after changing rear diffs.
Manual or automatic, the speedometer pinion is the same.
Tip: Only lift truck from the rear when changing. In this manner, all the fluid/lubricant will flow to front of the transmission and you won't need to drain anything (or get a bath) when you remove the pinion.
Tip: Only lift truck from the rear when changing. In this manner, all the fluid/lubricant will flow to front of the transmission and you won't need to drain anything (or get a bath) when you remove the pinion.
1*1971 D100 318 A/T
1*1970 Charger R/T 440-6PK A/T
2*1969 Daytona Charger 440 A/T
1*1969 Coronet R/T awaiting restoration
1*1969 Torino Talladega awaiting restoration
1*1970 Charger R/T 440-6PK A/T
2*1969 Daytona Charger 440 A/T
1*1969 Coronet R/T awaiting restoration
1*1969 Torino Talladega awaiting restoration