Speedometer gear?
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Cargo Master
Joined: Oct 2005
Posts: 2,295
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From: NJ
Speedometer gear?
Truck is an '86 F-250 Supercab with 3.55:1 gears and 25x12.5 BFG Mud Terrain with NP208 transfer case. Going to be swapping to a fixed yoke manual shift BW1356 soon. Speedo gear I got after the tires might have been wrong (auto trans maybe?) and was off on tooth count. It read closer but still about 5 MPH off around town and almost 10 MPH off on the highway. It stripped out some of the teeth on the driven gear though and the speedo bounces around at lower speeds. How amny teeth are on the drive gear on a NP208 and on a BW1356? How many teeth do I need on the driven gear? Anyone know the exact gear I need for this application? I don't want to wind up stripping out another gear and I'd like to be more accurate on the speedo if possible.
Elder User
Joined: Nov 2004
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I am not familiar with the drive gears for the transfer cases, but I know that for the T18 there are 3 different drive gears - 7, 8, and 9 tooth. I would suspect that there would also be a range of gears for the transfer case.
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Cargo Master
Joined: Oct 2005
Posts: 2,295
Likes: 25
From: NJ
Yeah I'm not sure what's in the transfer case but before I put the BW1356 in I'll crack the case to inspect it and check the teeth on the gear. Do they interchange with other cases and transmissions? As in, if the tooth count is too low so as to need a ridiculously high tooth count on the driven gear (weak teeth) can I swap to a higher tooth count drive gear to get my desired ratio with less teeth on the driven gear?
Also, what type of gear do transfer cases take? There seem to be either automatic trans or manual trans gears and nothing says transfer case specific. Leaves me wondering.
Also, what type of gear do transfer cases take? There seem to be either automatic trans or manual trans gears and nothing says transfer case specific. Leaves me wondering.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
16 thru 21 tooth nylon speedo DRIVEN gears (end of the cable) are available from Ford. The same ones have been used since 1960. Prices range from 2 to 4 bucks each.
There are four different nylon DRIVE gears (on the output shaft), have either 6, 7, 8 or 9 teeth.
The tooth count for these gears depends on the rear axle ratio, trans type and tire size.
Note: There are no DRIVE gears available for a C4 or C6, as they are made as part of the output shaft.
There are four different nylon DRIVE gears (on the output shaft), have either 6, 7, 8 or 9 teeth.
The tooth count for these gears depends on the rear axle ratio, trans type and tire size.
Note: There are no DRIVE gears available for a C4 or C6, as they are made as part of the output shaft.
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