Gear ratio?
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Freshman User
Joined: Dec 2002
Posts: 34
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From: Virginville Pa. USA
Gear ratio?
'85 F150, 300 six, 3sp w/od. This thing is geared way to tall. When I jacked up rear wheel and turn it 1 turn the driveshaft only turns less that 1 1/4 turns. What ratio is this.
Posting Guru
Joined: Dec 1999
Posts: 1,903
Likes: 2
From: Copley, OH
Gear ratio?
What was the other wheel doing? Assuming you have an open differential and that the other wheel was on the ground, it sounds like you have the dreaded 2.47:1 ring and pinion. You're right, it's way too tall.
What does the vehicle ID sticker on the door jamb list as the code under "axle"?
What does the vehicle ID sticker on the door jamb list as the code under "axle"?
Thread Starter
|
Freshman User
Joined: Dec 2002
Posts: 34
Likes: 0
From: Virginville Pa. USA
Gear ratio?
>What was the other wheel doing? Assuming you have an open
>differential and that the other wheel was on the ground, it
>sounds like you have the dreaded 2.47:1 ring and pinion.
>You're right, it's way too tall.
>
>What does the vehicle ID sticker on the door jamb list as
>the code under "axle"?
Yes it is an open differential and the other wheel was on the ground.
This sticker looks incomplete. All it has is a B in between the trans and axle space. What ratio would work good with this 3sp w/od trans.
Would like to gear it down and use it as a regular 4sp. Any ideas as what to look for in the junk yard? Thanks for your help.
>differential and that the other wheel was on the ground, it
>sounds like you have the dreaded 2.47:1 ring and pinion.
>You're right, it's way too tall.
>
>What does the vehicle ID sticker on the door jamb list as
>the code under "axle"?
Yes it is an open differential and the other wheel was on the ground.
This sticker looks incomplete. All it has is a B in between the trans and axle space. What ratio would work good with this 3sp w/od trans.
Would like to gear it down and use it as a regular 4sp. Any ideas as what to look for in the junk yard? Thanks for your help.
Posting Guru
Joined: Dec 1999
Posts: 1,903
Likes: 2
From: Copley, OH
Gear ratio?
B is the tranny code. With no axle code, I'm guessing it is a 2.47, but re-check before you do anything. Make sure the offside wheel is firmly on the ground, turn the wheel through 2 full revs and count the shaft revs. The number of revs is your ratio.
Your tranny has a .79:1 OD IIRC. With that I'd guess you'd want either a 3.27 or a 3.55 ratio. With stock 29" tires that would put you at about 2000 or 2200 RPM respectively at 65 MPH and give you a whole lot better acceleration than what you have now.
If you were to change to a T-18 or an NP 435, you might find the 2.47 a lot more acceptable, but a 2.73 or 3.08 would be way more useful.
Your tranny has a .79:1 OD IIRC. With that I'd guess you'd want either a 3.27 or a 3.55 ratio. With stock 29" tires that would put you at about 2000 or 2200 RPM respectively at 65 MPH and give you a whole lot better acceleration than what you have now.
If you were to change to a T-18 or an NP 435, you might find the 2.47 a lot more acceptable, but a 2.73 or 3.08 would be way more useful.
