Rear Axle Question ... 9 inch v 8.8 inch - Page 3 - Ford Truck Enthusiasts Forums

Notices
1948 - 1956 F1, F100 & Larger F-Series Trucks Discuss the Fat Fendered and Classic Ford Trucks

Rear Axle Question ... 9 inch v 8.8 inch

  #31  
Old 07-17-2015, 10:51 PM
mustangmike6996's Avatar
mustangmike6996
mustangmike6996 is offline
Elder User
Join Date: Jun 2013
Location: Metro Detroit-MI
Posts: 946
mustangmike6996 has a good reputation on FTE.mustangmike6996 has a good reputation on FTE.
The Ford 8.8 Mustang Rear End - Car Craft Magazine

If you are concerned about 8.8 rear end strength, get the 31 spline axles (Explorer and late model Mustang)
 
  #32  
Old 07-21-2015, 09:11 PM
Flat Ernie
Flat Ernie is offline
Senior User
Join Date: Jul 2003
Location: FL
Posts: 322
Flat Ernie is gaining momentum as a positive member of FTE.
Originally Posted by mustangmike6996 View Post
The downfall of the 8.8 is the axle tubes not being welded.

The downfall of the 9 inch is the flex in the housing.

The upside of the 9 inch is the endless amount of parts available (at a $$ price)

The upside of the 8.8 is the standard Trackloc and disc brakes for a fraction of the cost.
Originally Posted by mustangmike6996 View Post
The Ford 8.8 Mustang Rear End - Car Craft Magazine

If you are concerned about 8.8 rear end strength, get the 31 spline axles (Explorer and late model Mustang)
The strength of the 9" comes from it's pinion snout bearing. The 8.8 is an excellent rear, and I do not doubt its strength - they are on par with a GM 12-bolt. The 9" is still king when it comes to all-out strength though and why they're used in every form of racing (even if there isn't a single 'Ford' piece in them). If your housing is flexing, you've got bigger issues to fix!

Another huge advantage for many people using the 9" in this particular niche of the hobby is the ability to retain the stock 5 on 5.5" bolt circle...those don't exist with the 8.8.

The bottom line is, they're both good axles.
 
  #33  
Old 07-21-2015, 09:22 PM
ALBUQ F-1's Avatar
ALBUQ F-1
ALBUQ F-1 is online now
Post Fiend
Join Date: Jul 2004
Location: NM
Posts: 23,751
ALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputation
Originally Posted by Flat Ernie View Post
The strength of the 9" comes from it's pinion snout bearing. ...
I got a chuckle out of that magazine comparison where the pinion shaft diameter of the 8.8 was much larger than the 9", like that was an advantage. In reality it's a testament to the effectiveness of the snout bearing versus the overhung design of most other diff's.
 
  #34  
Old 07-22-2015, 10:19 PM
Flat Ernie
Flat Ernie is offline
Senior User
Join Date: Jul 2003
Location: FL
Posts: 322
Flat Ernie is gaining momentum as a positive member of FTE.
Originally Posted by ALBUQ F-1 View Post
I got a chuckle out of that magazine comparison where the pinion shaft diameter of the 8.8 was much larger than the 9", like that was an advantage. In reality it's a testament to the effectiveness of the snout bearing versus the overhung design of most other diff's.
Just like a bolt in double-shear is stronger than a larger bolt in single shear...those gears are trying to get away from each other and there's a lot of force working it...
 
  #35  
Old 07-22-2015, 10:52 PM
ryans88gt's Avatar
ryans88gt
ryans88gt is offline
Senior User
Join Date: Oct 2013
Posts: 386
ryans88gt is gaining momentum as a positive member of FTE.ryans88gt is gaining momentum as a positive member of FTE.
what is the strongest rear axle... ha ha ha...

what's the best carb will be the next discussion.

I think the OP has received some good advice keeping/ rebuilding the stock axle.
 
  #36  
Old 07-24-2015, 10:04 AM
rio68's Avatar
rio68
rio68 is offline
Senior User
Join Date: Jul 2015
Posts: 100
rio68 is starting off with a positive reputation.
When replacing a Dana 44 out of a 1955 f100 the link here says 72 is a direct exchange...some other info indicates 76 works. Does anyone know what the difference is if any?? Thanks for any help!
 
  #37  
Old 07-24-2015, 12:39 PM
AXracer's Avatar
AXracer
AXracer is offline
Post Fiend
Join Date: Oct 2004
Location: Durham NC
Posts: 15,754
AXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud ofAXracer has much to be proud of
An unmentioned possible disadvantage of the 8.8 is it is too narrow for our trucks, requiring strongly offset wheels or wheel spacers. That can be an advantage tho if you want a different bolt pattern, you can use all in one spacers and BP converters. Advantage of the 8.9 is they are very available (hence inexpensive) and come in a number of different gear ratios, with/without LSD, with/without disk brakes. I am running 3.70 ratio with my double OD T56 6 speed (.66 5th, .50 6th) and find it a perfect combo, loafs along at 80MPH in 6th while getting 26+ MPG.
 
  #38  
Old 07-24-2015, 01:16 PM
rio68's Avatar
rio68
rio68 is offline
Senior User
Join Date: Jul 2015
Posts: 100
rio68 is starting off with a positive reputation.
That's the ultimate goal is 5spd and larger engine. Right now it is 272 V8 with a Mustang 4spd but the rear diff. needs rework. didn't want to redo it but switch to 9 inch for its advantages. Just found some 73 model up rear assy. and didn't know what the difference from a 72 if a 72 was pretty much a direct bolt in what would be the issues in using later model.
 
  #39  
Old 07-24-2015, 02:05 PM
ALBUQ F-1's Avatar
ALBUQ F-1
ALBUQ F-1 is online now
Post Fiend
Join Date: Jul 2004
Location: NM
Posts: 23,751
ALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputation
The '73 - on F-100 axles are quite a bit wider, don't have the numbers handy but I think it's about 4".
 
  #40  
Old 07-24-2015, 02:19 PM
Last chance 53
Last chance 53 is offline
Senior User
Join Date: Oct 2013
Posts: 132
Last chance 53 is gaining momentum as a positive member of FTE.Last chance 53 is gaining momentum as a positive member of FTE.
For me the down side of a 8.8 is the c clip axles and rear axle bearing design. Mid 80's thru 1996 f150 have 5x5.5 axle pattern
 
  #41  
Old 07-24-2015, 11:19 PM
rio68's Avatar
rio68
rio68 is offline
Senior User
Join Date: Jul 2015
Posts: 100
rio68 is starting off with a positive reputation.
Picked up 72 F100 9" axle assy now to check it out and figure out best way to bolt it down. Shock mtg cradle is cupped for 2.5" tube this is 3" tube. Shocks are mtg to brackets welded to the tube on the frt side of 9" assy and my Dana assy had shocks mtg to the rear of the tube and bolting to the bracket that served as the bottom mtg. Anyone been down this road and have some pics of how they mounted a 9" in place of the Dana 8.8?
Thanks...
 
  #42  
Old 07-25-2015, 12:05 AM
ALBUQ F-1's Avatar
ALBUQ F-1
ALBUQ F-1 is online now
Post Fiend
Join Date: Jul 2004
Location: NM
Posts: 23,751
ALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputation
  #43  
Old 07-25-2015, 10:02 PM
rio68's Avatar
rio68
rio68 is offline
Senior User
Join Date: Jul 2015
Posts: 100
rio68 is starting off with a positive reputation.
Originally Posted by ALBUQ F-1 View Post

Thanks for the info--helped a lot. Cut the brackets for shock mtg off and the bone yard saved the U-bolts but guess I'd better get new ones. Going to call Midfifties Monday and see what they have. Be nice to find a bottom plate like the original made for 3 inch tubes.
 
  #44  
Old 07-25-2015, 10:29 PM
ALBUQ F-1's Avatar
ALBUQ F-1
ALBUQ F-1 is online now
Post Fiend
Join Date: Jul 2004
Location: NM
Posts: 23,751
ALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputationALBUQ F-1 has a superb reputation
If you can find an F-2 or F-3 lower spring plate, they had 3" tubes on their axles. Alternatives are later model F-100 spring plates, and (gasp) Chevy Sierra-class plates. I used the Chev parts because they are mondo heavy duty stampings. As I recall, what MidFifty sells is a flat plat that IMO has no rigidity. These are the Chev parts, note the holes need to be worked a little because the Chev springs are slightly angled.


 
  #45  
Old 07-31-2015, 09:21 PM
rio68's Avatar
rio68
rio68 is offline
Senior User
Join Date: Jul 2015
Posts: 100
rio68 is starting off with a positive reputation.
Anyone have a recommendation on adding a limited slip unit to a 9" rear. Moser shows one but I don't know anything about them. My son and I are cleaning and getting new parts for the 9" and want to add this type unit to the assy. Thanks..
 

Thread Tools
Search this Thread
Quick Reply: Rear Axle Question ... 9 inch v 8.8 inch


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.