diff question
Thread Starter
|
Laughing Gas
Joined: Dec 2009
Posts: 938
Likes: 0
From: Bishop, CA
diff question
I'm wanting to use the 3rd memeber from my '82 donor truck in my '61 project so the gears will match the trans and engine I'm swapping in. Also, the old rear end is about shot.
The only problem I have is that the newer diff is a 31 spline and the old truck is, of course, the 28 spline version. The '82 housing is like 5" wider than the '61, so a complete swap is out of the question.
I've been told that the side gears will interchange and that all I have to do is get a new set of side and spider gears with the 28 spline count and put in the newer 3rd member.
Anybody know for sure?
The only problem I have is that the newer diff is a 31 spline and the old truck is, of course, the 28 spline version. The '82 housing is like 5" wider than the '61, so a complete swap is out of the question.
I've been told that the side gears will interchange and that all I have to do is get a new set of side and spider gears with the 28 spline count and put in the newer 3rd member.
Anybody know for sure?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
I'm wanting to use the 3rd memeber from my '82 donor truck in my '61 project so the gears will match the trans and engine I'm swapping in. Also, the old rear end is about shot.
The only problem I have is that the newer diff is a 31 spline and the old truck is, of course, the 28 spline version. The '82 housing is like 5" wider than the '61, so a complete swap is out of the question.
I've been told that the side gears will interchange and that all I have to do is get a new set of side and spider gears with the 28 spline count and put in the newer 3rd member.
Anybody know for sure?
The only problem I have is that the newer diff is a 31 spline and the old truck is, of course, the 28 spline version. The '82 housing is like 5" wider than the '61, so a complete swap is out of the question.
I've been told that the side gears will interchange and that all I have to do is get a new set of side and spider gears with the 28 spline count and put in the newer 3rd member.
Anybody know for sure?
Without it, there is no way to know which spider gears your truck has now, as two different types were used 1957/86.
The side gears are the same thru 1968, then there are two different types used 1969/86.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Old Crow, you can bolt the complete donor under your truck as an option, The track is wider but it will work, provided you are referencing a F150 that has the same wheel lug pattern as the front and not a F100.
John
John
Thread Starter
|
Laughing Gas
Joined: Dec 2009
Posts: 938
Likes: 0
From: Bishop, CA
Well, it snowed another d--n foot today, so it'll be a while before I get the tag #'s. 
John, I had originally planned to use the whole thing until I measured it. If it was just an inch or so per side, maybe, but 2 1/2" would just look silly and I think it'd create tire clearance problems with the fenders.
If I can't swap out the 3rd member, I'll talk to the local junkyard. They're already gonna pick up what's left of my donor truck when I'm finished...maybe I can work out a trade on a complete rear end that'll fit.
Interesting little deal, Friday at work, I measured a driveshaft to have it altered on a '69 Mach I. This weekend I measured my truck. Both shafts measured the exact same measurement. Hmm.
John, I had originally planned to use the whole thing until I measured it. If it was just an inch or so per side, maybe, but 2 1/2" would just look silly and I think it'd create tire clearance problems with the fenders.
If I can't swap out the 3rd member, I'll talk to the local junkyard. They're already gonna pick up what's left of my donor truck when I'm finished...maybe I can work out a trade on a complete rear end that'll fit.
Interesting little deal, Friday at work, I measured a driveshaft to have it altered on a '69 Mach I. This weekend I measured my truck. Both shafts measured the exact same measurement. Hmm.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Don't think it is 5 in., re-check it backing plate to backing plate. Wheels can make a difference. The wider rear will bring the tires closer to the body for sure.
You can swap a 9in 28 spline with another for sure.
John
You can swap a 9in 28 spline with another for sure.
John
Elder User
Joined: Nov 2005
Posts: 998
Likes: 2
From: Benton, AR
My bed is now on a 79 frame and axel. The stock wheels will fit inside the fenders without rubbing. Now if you want to change out to some nicer wheels then you will run into clearance issues and you will need to find the correct offset. So yes the axel is probably wider, but it will likely fit. Not sure if your current spring perches and shock mounts will be the same. Might require some grinding and rewelding on your part.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
My bed is now on a 79 frame and axel. The stock wheels will fit inside the fenders without rubbing. Now if you want to change out to some nicer wheels then you will run into clearance issues and you will need to find the correct offset.
So yes the axel is probably wider, but it will likely fit. Not sure if your current spring perches and shock mounts will be the same. Might require some grinding and rewelding on your part.
So yes the axel is probably wider, but it will likely fit. Not sure if your current spring perches and shock mounts will be the same. Might require some grinding and rewelding on your part.
Some 1980/83 F100's have 5 lug wheels on a 5.50" bolt circle.
Some 1980/83 F100 have 5 lug wheels on a 4.50" bolt circle.
Some 1980/83 F100's have 10 inch rear brakes.
Some 1980/83 F100's have 11 x 2 1/4" rear brakes, as do all 1968/79 F100's and 1975/96 F150's.
If the donor truck has 4.50" wheels, the OP will need to carry two spares if he installs the whole tamale.
1980/83 F100 & 1980/96 F150: The rear spring width is 3 inches.
The OP's 1961 F100's rear spring width is 2 1/4 inches.
1980 and later F100/150: The spring shackles, front/rear spring mounting brackets, shock mounts and etc are not the same as 1961/72 F100's, most 1973/79 F100/150's.
Trending Topics
Thread Starter
|
Laughing Gas
Joined: Dec 2009
Posts: 938
Likes: 0
From: Bishop, CA
Bill, the donor truck is a 150. My '61 is already wearing the tires and wheels off the donor truck(no use letting good rubber sit and rot).
I'll take a closer look and remeasure everything when the snow is not piled 18" deep around the truck. Couldn't get the thing out of my driveway even if I got it running this very minute, so no real big hurry, I guess.
I'll take a closer look and remeasure everything when the snow is not piled 18" deep around the truck. Couldn't get the thing out of my driveway even if I got it running this very minute, so no real big hurry, I guess.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
FordNFishinLover
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
65
Apr 23, 2011 05:40 PM
The_SnowMan710
Clutch, Transmission, Differential, Axle & Transfer Case
2
Dec 31, 2010 01:01 AM
