Rear Axle Question ... 9 inch v 8.8 inch

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#46

08-01-2015, 12:58 AM

das54

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My 54 had an open 9 inch with 2.91 gears and it would just spin one tire on wet pavement. I looked at putting a detroit true trac in it but it does not work with gears less than 3.25 because the ring gear is the wrong size and I didn't want to get into the extra cost or work to change out the ring and pinion. My front had 5 on 4.5 so I swapped in a 98 explorer 8.8 with 3.73 posi and disk brakes.

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#47

08-01-2015, 02:38 PM

underthebridgejim

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Quote:

Originally Posted by das54

This is the one I chose but have not put into service yet. This is also my first rear end build, so as for its overall quality Ill just have to wait and see. Money was definitely a factor when choosing it. Good luck on your build. http://www.summitracing.com/parts/su...cl31/overview/ EDIT Sorry I meant to hit quote on Rio68s post #45, and accidently hit post #46. OOPS

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#48

08-01-2015, 02:58 PM

rio68

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Mine has a 3.50 ratio so the size of the ring and pinion shouldn't be a problem. I just hope someone has used the Moser unit and can shed some light on the product.

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#49

08-09-2015, 07:58 PM

rio68

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Got my 9" housing under the 55 F100 and bolted down. Problem I have is the pinion angle looks like it will be way off. Looking for someone who has put a 9" out of a 72 F100 into the older (55) trk. Question is does the mounting pads have to be moved because of the angle in most cases or do they mostly match up ok?

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#50

08-10-2015, 12:15 AM

AXracer

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Unless you have done major suspension mods pinion angle should be close enough to adjust with tapered shims. Be sure to measure with truck full weight on suspension (final ride height). Pinion angle should match engine/tranny angle (NOT line up in direct line with tranny!) at FRH.

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#51

11-06-2018, 12:28 PM

mttrooper

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Read the article, but have a question.

Quote:

Originally Posted by ben73058

Hey Jeff,
Here is an article that goes through the rear axle solutions with some thoughts on each.

1948 through 1960 Ford F-1 and F-100 Rear Axle (differential) Swaps - Ford-Trucks.com

Ben in Austin
1950 F1

I really liked the post. It made a lot of sense to me. I was wondering if there was an issue with the driveline matching up. Does it matter if you have an automatic or manual transmission, and if a manual, whether a column or floor shift. I have a 4sync on the floor. The reared is the original DANA44, and is very low geared. You can put it in first and get out and walk along side without any problem. So, my interest in switching to a 9” rear end. Thanks. Bryan

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#52

11-06-2018, 01:03 PM

ben73058

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Hey MT Trooper,
Welcome aboard! Show us some pics of your truck when you get a chance. It would be nice to
see what you are working on up there in Montana. I personally don't think it matters what engine/trans
you are running when choosing your 9 inch rear end. Other's will chime in with their thoughts & opinions.

When we got our 8.8 Explorer axle from a salvage place we also got the emergency brake set up
that went with that axle. We didn't have one & that Explorer one has worked out real well for us.

Ben in Austin
1950 F1

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#53

11-06-2018, 03:23 PM

mttrooper

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Quote:

Originally Posted by ben73058

Thanks, Ben. I’ve had my 55 f100 for about 5 years now. Rebuilt the 272 that was in it, and have been driving it for about 2 months now. I don’t know if the site will let me post pics, but I’ll try. I put 16” wheels with 6ply tires on it, and it seems like the speedo shows the right mph. I can do 75mph+, but I don’t like how the engine sounds at that speed. 60 is about right. Since I’m not a rancher/farmer, I plan on taking it on road trips, and want to tow a small trailer. So, I’m interested in a gear ratio that will do the job. Have any ideas? Thanks. Bryan

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#54

11-06-2018, 04:07 PM

abe

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Trooper, welcome to FTE the best Ford truck Forum on the world wide web!

Start a build thread and include some history and pics of your truck when you get the hang of it. There is a sticky thread, which always stays at the top of the 48-56 forum, which explains how to post pics.

Is your truck a 3 speed on the column or 4 on the floor with first being a granny gear?

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#55

11-06-2018, 05:25 PM

mttrooper

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Quote:

Originally Posted by abe

Thanks Abe. I’ll post some pics as soon as I can take them. It’s got the 4sync on the floor with 1st as granny.

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#56

11-06-2018, 06:24 PM

abe

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The granny gear was made for things just what you described. On the farm my Dad would put his 48 Check 3/4 ton in 1st gear and pull out the hand throttle a bit as we would walk along side and pick corn or in the spring after plowing, picking rocks. When I was wee little I'd sit behind the wheel and steer and push the clutch in when told to.

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#57

11-08-2018, 03:11 PM

mttrooper

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55 f100

Quote:

Originally Posted by mttrooper

Thanks Abe. I’ll post some pics as soon as I can take them. It’s got the 4sync on the floor with 1st as granny.

I’m not sure how to start a build thread, so I’ll keep posting to this thread by adding a few pics (if I can).

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#58

11-08-2018, 03:30 PM

56panelford

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Quote:

Originally Posted by mttrooper

I’m not sure how to start a build thread, so I’ll keep posting to this thread by adding a few pics (if I can).

Go to this link and click on the NEW THREAD button that is orange in color and start your build thread there..
https://www.ford-trucks.com/forums/forum41/

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#59

11-08-2018, 08:26 PM

ben73058

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Hey Bryan,
That's a nice looking solid truck! I can't believe you guys already have snow on the
ground up there.... uggh…..

We are running 3.73 rear gears but we have a much different engine/trans set up.
We need to get others who are more stock to chime in what gearing would work best.

Ben in Austin
1950 F1

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