M50D-R1 speedometer gear

[EvanCole45]

Hey guys, I need to get a remanufactured transmission for my 1988 Ford Ranger GT. I’m wondering if my truck has a 6,7, or 8 tooth speedometer gear. I hope someone can help me out with this.
thanks!

 

[RonD]

Manual trans and 4WD transfer case should be 7 tooth drive gear

 

[scotts90ranger]

It's hard to tell, would be easiest to take the speedo gear out (one bolt with 7/16" head I believe) and look in the hole, the different gears are different colors I think white, yellow and red if memory serves.

 

[Shran]

Manual trans and 4WD transfer case should be 7 tooth drive gear

He's got a GT which would be 2wd... does that still ring true in this situation? Been quite a while since I've dealt with a 2wd truck.

 

[RonD]

Yes, all Rangers with 2WD manual trans used 7 tooth drive gear, but it could be swapped/removed
2WD Automatics(C3 to 4R55E) used 8 tooth but it was machined onto the tail shaft

4WD transmissions didn't have speedo drive gear, short tail shaft, manual or auto
The transfer case had the speedometer gear, all 7 tooth, and swap-able/removable

1998 and up Rangers started to lose the speedo drive gears, 2WD automatics still had them up to about 2001/2 but no hole in tail shaft housing for the driven gear
2WD manuals didn't have the gear installed or the hole
Around 2001/2 Ford start using an OSS(output shaft speed) sensor on the rear of the transmission, 2WD or 4WD, manual or auto, these used a Tone wheel on the shaft, not a gear
For 4Low the computer would recalculate speed signal sent to speedometer, for the higher Ratio

 

[4x4junkie]

4WD transmissions didn't have speedo drive gear, short tail shaft, manual or auto
The transfer case had the speedometer gear, all 7 tooth, and swap-able/removable

The 1350 t-case out of my '90 has a red 6-tooth gear. I think it's only 1354s that have 7-tooth gears.

 

[RonD]

Certainly possible, it comes down to axle ratios and tires sizes offered on that year
But if you have to "guess" use 7 tooth with Rangers
Common size Driven gears are 16 to 21 teeth

7 tooth drive with 4.10 ratio and 35" tire uses 16tooth
7 tooth w/3.73 and 27" tires use 21tooth

 

[Osinski91b]

Does anyone have a part number and an equation for figuring out what tooth number is needed. I have a 1990 ranger 4x4 manual with 285/65R16 tires

 

[RonD]

Does anyone have a part number and an equation for figuring out what tooth number is needed. I have a 1990 ranger 4x4 manual with 285/65R16 tires

Welcome to TRS

You also need your rear axle ratio

Look on drivers door back edge, there will be a label there with vehicle info
Look at the bottom, under AXLE will be a 2 digit code number

Then go here to look it up: https://www.therangerstation.com/tech_library/axle_codes.shtml

Your 285/65R16 tires are 30.6" diameter you need that as well

Then go here: https://www.tciauto.com/speedometer-gear-calculator

Go down to
Speedometer Gear Calculator
You have a 7 tooth DRIVE
Ratio ???
Tire 30.6

It will tell you how many teeth should be on the Driven gear

 

[Osinski91b]

It is a 3.73 ratio. Sorry I forgot to put that in. Thanks for the info. Still trying to find where I can find a new gear. Anytime I search Google it brings up gears for the t5 transmission

 

[Curious Hound]

It is a 3.73 ratio. Sorry I forgot to put that in. Thanks for the info. Still trying to find where I can find a new gear. Anytime I search Google it brings up gears for the t5 transmission

Last time I needed one, I think I ordered it from Jeff’s Bronco Graveyard.

 

[RonD]

Yes, bronco grave yard seen here: https://shop.broncograveyard.com/Speedo-driven-gear-17-teeth-white-color/productinfo/37192B/

$7, shipping is $8, lol

 

[Curious Hound]

It’s as if you’re the tooth fairy paying $1 per tooth. I think BG had the best price I found a few years ago.

 

[Osinski91b]

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Same thing I have been seeing that says it is for the c4,c6,t5 ECT.