Another diff ratio question.

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Aug 11, 2015 | 10:35 AM

tiger100

Thread Starter

Mountain Pass

Joined: Dec 2014

Posts: 109

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Another diff ratio question.

My 51 F1 has 427 stamped on the passenger side rear axle tube. I jacked up one wheel and market the tyre and drive shaft and gave the wheel a spin. For two revolutions of the wheel the drive goes 'round approx 4 and a quarter times.Being inquisitive I had to have a look inside, the numbers on the crown wheel? are 1M4210-B and 11x47 and 1-51 and a C.
It looks like there are several chipped teeth on one of the Planetary? gears and the bolts holding the bearings weren't really done up properly.
(1) Is this diff higher ratio than most F1's or a super low ''tree climber''.
(2) If its a higher ratio than normal would it be better to replace chipped teeth etc, than to take a chance on a 9'' 28 spline Ford diff that's an unknown?
(3) Can someone tell me the torque settings for the bearing caps, please.
Once again, Thanks to each and everyone who answers.
Geoff.

Aug 11, 2015 | 11:03 AM

Jolly Roger Joe

Lead Driver

Joined: Jul 2011

Posts: 6,599

Likes: 34

From: Rockingham, VA

Quote:

Originally Posted by tiger100

The F1 had two gear ratios available, 4.27 and 3.92.

Aug 11, 2015 | 04:53 PM

38 coupe

Cargo Master

Joined: Aug 2010

Posts: 2,916

Likes: 125

From: Houston

If your gears are chewed up you probably should replace them, along with the bearings in the area. Or find another F-1 axle from someone hot rodding their truck. If you want to rebuild and re-gear your stock axle it can be done but the parts are expensive.

Aug 14, 2015 | 08:51 AM

tiger100

Thread Starter

Mountain Pass

Joined: Dec 2014

Posts: 109

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another Diff ratio question

Jolly Roger Joe and 38coupe, thanks for the answers to my post.
I appreciate the fact that I would have to replace chipped gears etc, IF I was going to re-use this diff. and i understand that to regear it would be expensive......something about these old trucks is cheap?
However this doesn't answer my questions.
Surely someone has the answers......
Geoff.

Aug 14, 2015 | 09:55 AM

52 Merc

Hotshot

Joined: Oct 2009

Posts: 16,135

Likes: 4,735

From: Burbank, WA

What question? As the others stated, your gear ratio is common (normal), depending on which option box the original purchaser checked. Getting the same or different gears in a used axle assembly is a crap shoot. There were only a couple of options. You've noted your gears are chewed up and your bearings are loose, so your axle is essentially junk. If you're going to rebuild it yourself, get a shop manual so you have the instructions and specifications you need for reassembly. Or are these just not the answers you wanted to hear?

Aug 14, 2015 | 12:25 PM

ALBUQ F-1

Fleet Owner

Joined: Jul 2004

Posts: 27,283

Likes: 1,046

From: NM

No matter how you address the problems, I'd figure on it costing you $700 - $1000. That's whether you have the existing axle rebuilt, put in a well-used 9", go with Explorer, etc. So decide what you want to end up with first.

Aug 14, 2015 | 02:21 PM

underthebridgejim

FTE fan

Joined: Dec 2006

Posts: 3,674

Likes: 11

From: paradise, northern calif.

Hi Geoff, a picture may be very helpful for the guys trying to help you diagnose your problem. If your tube is stamped 427 odds are that you have the 4.27 gear option, If you still have the cover off and can snap some pics of what you are describing it would allow them to give you more informed answers. As I understand it the higher the # the lower the gear, the lower the # the higher the gear. Best of luck on your rear end. If you do not know how to post a picture click on the third READ FIRST thread on the top of the main page. It explains how.