How to identify locking front differentials
New User
Joined: Jan 2001
Posts: 3
Likes: 0
How to identify locking front differentials
I've been looking at 70-79 4WDs to replace my 1970 (I sold 25 years ago), but I'm stumped because I really want the front differential to be locking or limited slip.
Problem is most owners don't know if theirs is locking or not. My Ford dealer says you might be able to tell from seeing an "L" on a metal ID tag on the axle. (But he says that most of the tags are removed during rebuilds and I guess he's right since I've seen no tags.)
Can anyone help tell me what to look for or the easiest way to test?
Does anyone think I'm crazy to worry about this? (My feeling is it would be a big help when the going gets tough on steep gravely/snowy backroads here in Oregon and possibly delaying chaining up.
Thanks from a new member...
Problem is most owners don't know if theirs is locking or not. My Ford dealer says you might be able to tell from seeing an "L" on a metal ID tag on the axle. (But he says that most of the tags are removed during rebuilds and I guess he's right since I've seen no tags.)
Can anyone help tell me what to look for or the easiest way to test?
Does anyone think I'm crazy to worry about this? (My feeling is it would be a big help when the going gets tough on steep gravely/snowy backroads here in Oregon and possibly delaying chaining up.
Thanks from a new member...
Cargo Master
Joined: Jul 2000
Posts: 2,281
Likes: 18
From: Northern California
How to identify locking front differentials
Jack up ONE front tire and try to spin it, if it spins, its open. Most fronts are open, better for steering. partial lockers are about $300 for the front.
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
How to identify locking front differentials
If it spins freely it's open. I have a factory "L" frontend
and you can turn one wheel but it has a noticeable drag to it.
I agree about the steering situation. In the snow when I am
in 4x4 and want to make a sharp turn, like turning off a main
road on to a side road, I have to come basically to a stop or the truck will not turn. On gentle turns if I don't let off
the throttle, it won't turn either. When I say it won't turn
I mean you can turn the steering wheel as far as you want and
the truck will not react even the slightest bit. I have a factory limited slip rear too, and if you have the room to play
the truck does some pretty weird things. If you cut the wheel
as hard as you can, like I said the front won't turn but the
backend will slowly come around and if you time it right you can
punch the gas when you are pointed in the right direction. I'll
have to admit that is fun.
and you can turn one wheel but it has a noticeable drag to it.
I agree about the steering situation. In the snow when I am
in 4x4 and want to make a sharp turn, like turning off a main
road on to a side road, I have to come basically to a stop or the truck will not turn. On gentle turns if I don't let off
the throttle, it won't turn either. When I say it won't turn
I mean you can turn the steering wheel as far as you want and
the truck will not react even the slightest bit. I have a factory limited slip rear too, and if you have the room to play
the truck does some pretty weird things. If you cut the wheel
as hard as you can, like I said the front won't turn but the
backend will slowly come around and if you time it right you can
punch the gas when you are pointed in the right direction. I'll
have to admit that is fun.
New User
Joined: Dec 2004
Posts: 1
Likes: 0
identify differentials
http://www.drivetrain.com/Fordtrkratio_posidata.html#differential 
should help to identify your differential ford limited slip is worthless Iam going to try powertrax& lockright ,ease 0f install
and 95% on road but need the traction of all 4 when I want it !!!i
should help to identify your differential ford limited slip is worthless Iam going to try powertrax& lockright ,ease 0f installand 95% on road but need the traction of all 4 when I want it !!!i
FTE Leadership Emeritus
Joined: Jan 2003
Posts: 161,999
Likes: 75
From: 3rd Rock
Originally Posted by haddanuff
http://www.drivetrain.com/Fordtrkratio_posidata.html#differential should help to identify your differential ford limited slip is worthless Iam going to try powertrax& lockright ,ease 0f install
and 95% on road but need the traction of all 4 when I want it !!!i
should help to identify your differential ford limited slip is worthless Iam going to try powertrax& lockright ,ease 0f installand 95% on road but need the traction of all 4 when I want it !!!i
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Cross-Country
Joined: Dec 2003
Posts: 65
Likes: 0
From: Que. Canada
i have a limited slip in front and rear of my 78 bronco with a friction modifier in it and from straight to about 20degree turn i have all 4 biting if i step on it .if i ease into it i get 2 somtimes 3(1 front 1-2 rear) wheels grabbing.i have no problem in the mud or snow and i do alot of 45 degree traversing and posi hinders that if i spin not fun
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