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NEW Ford 9 Inch Posi Traction Third Member

SAME DAY SHIPPING! Order within the next 2 hours 5 minutes and receive same day shipping

Specs
Sold in Quantity:
Set
Spline Count:
-
Ring Gear Weight:
Standard
Differential Type:
Limited Slip
Spool Weight:
Standard
Housing Material:
Cast-Iron
Gear Ratio:
-
Garage Sale:
No
NEW Ford 9 Inch Posi Traction Third Member

Click image to enlarge

Details

Reviews

Q & A

What's in the Box

Our completely NEW 9" Ford third members start with a heavy duty cast iron carrier featuring the larger, cast iron Daytona pinion support. Then we use a Richmond Powertrax Grip Pro differential in your choice of 28 or 31 spline.

All third members are assembled by our team of professionals and are delivered to you in a handy plastic carrying case, for an overall value that can’t be beat

Available in your choice of 3.50, 3.70, 3.89, 4.11 or 4.56 gear ratio ring & pinion. 

Customer Reviews

Rated 4.3 out of 5 by 7 reviewers.
RATING BREAKDOWN
7 reviews
5 Stars
4
4 Stars
2
3 Stars
0
2 Stars
1
1 Star
0
RECOMMEND THIS PRODUCT:

Texas Attitude Racing
Verified Purchaser
Bandera, TX

Perfect

August 21, 2015
This diff worked nicely. The posi made zero noise which is opposite of the locker style diffs that are used in the 9" arena. Definitely recommend on a street/Pro-Street vehicle. Happy and will purchase again for the next customer needing the similar situation.
Yes, I recommend this product.
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Quickie70
Verified Purchaser
Morrison, CO, USA

5 stars for service but wouldn't recomme

February 08, 2015
For the money, this unit can't be beat. On paper. It's got a stout housing, name brand parts, and it's 1/2 the price of a "big name" assembled third member, however it comes down to assembly, and mine was poorly assembled. I broke it in and ran red line heavy shockproof oil, but the ring and pinion ate each other within 1200 miles, and really started making noise about a hundred miles from anywhere, which was unsettling. However, speedway made it right after I returned it and was offered and new product or a refund, so speedway rocks. Again.
Pros:
  • customer service is top notch
  • Inexpensive
  • Quality parts
Cons:
  • poor setup
No, I would not recommend this product.
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JTstunts1
Verified Purchaser

killer!

October 20, 2014
I build everything myself but this time I needed to get the car together faster so I bought the diff assy already built, awesome for the price and saved me hours!
Pros:
  • quality product super clean
Cons:
  • didn't come with1350 yoke but easy fix
Yes, I recommend this product.
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jeeddii
Verified Purchaser

this item is good value

August 03, 2014
I have built many differentals.The patterns are well placed so I feel it will run quiet.I fell the pinion preload is to tight which I wil look at before I put it in the car
Pros:
  • Good Value
Cons:
  • pinnion preload too tight
Yes, I recommend this product.
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negative
Verified Purchaser

The product looked great.

June 04, 2014
The item shipped was the wrong item. I ordered a 28 axle spline, but I received a 31 axle spline third member. So I was unable to use it.
Yes, I recommend this product.
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Merchant Response:

Speedway Motors Customer Service team has issued this customer a refund for the incorrect item received. We apologize for any inconvenience this may have caused.
papabear
Verified Purchaser
Missouri

Quality built at a great price.

March 03, 2013
Nicely painted and even included a bottle of friction additive for the posi unit.
Pros:
  • neat storage case is included
Cons:
  • does not come with a gasket
Yes, I recommend this product.
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Charlie "Nuts and Bolts"
Verified Purchaser
Hartsdale, NY

No Gasket

June 22, 2012
Not installed yet, have't had time to get a gasket yet..
Pros:
  • Good product fast shippin
Yes, I recommend this product.
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Page 1 of 1

Product Q&A

6 questions : 6 answers

1 answers

just want to buy the red plastic container for the 3rd member just want to buy the red plastic container for the 8inch 3rd member

Hiro
California, USA
March 29, 2014

just want to buy the red plastic container for the 3rd member just want to buy the red plastic container for the 8inch 3rd member

Answers

March 31, 2014
EricM
Sorry I only offer the plastic case for 9" Ford which is part number 91081080.
1 answers

Ratio Sir/Ma'am, Looking to use this with your triangulated 4 bar kit for a 52 Chevy 3100, has a 383 engine with 700R4 trans. What ratio do I need for this third member? Wife will use this to drive 20mi each way to work 3 times a week and give her a little thrill from time to time at take off. Not sure if 3:70 or the 3:89 would fit the bill? Thank you in advance for the reply I appreciate your time as always.

50Two
December 15, 2013

Ratio Sir/Ma'am, Looking to use this with your triangulated 4 bar kit for a 52 Chevy 3100, has a 383 engine with 700R4 trans. What ratio do I need for this third member? Wife will use this to drive 20mi each way to work 3 times a week and give her a little thrill from time to time at take off. Not sure if 3:70 or the 3:89 would fit the bill? Thank you in advance for the reply I appreciate your time as always.

Answers

December 16, 2013
EricM
The rear end gear ratio is highly subjective to the drivers preference. Either of those gear ratios would work fine. The 3.70 ratio will provide slightly less RPM while cruising down the highway than 3.89 would. With the low first gear ratio of a 700R4 I would personally use a 3.50 or 3.70 gear ratio unless you are only concerned about performance. If using large rear tires (30" or taller) you may want to be in the 3.70 to 4.11 range however.
1 answers

Which housing is used on this assembly? Also, what brand of gears does this include? Wondering which housing this is, only says new in title and heavy duty in description. Need more info. Also who's gears are installed for this? I'm looking at getting a 3.70 ratio if that makes a diff.

madsow
Chanute, ks
October 05, 2013

Which housing is used on this assembly? Also, what brand of gears does this include? Wondering which housing this is, only says new in title and heavy duty in description. Need more info. Also who's gears are installed for this? I'm looking at getting a 3.70 ratio if that makes a diff.

Answers

October 07, 2013
Jason
The housing on the 9" posi traction third member is Speedway part #91048390 that is a new 36 pound heavy duty cast iron case with 3.062" forged steel caps, 5/8" HD grade 8 cap bolts and good for 1100 plus horsepower. The ring and pinion is from Richmond Gear.
1 answers

how do I tell if I have a short or long yoke? does it make a difference?

David
Virginia Beach, Virginia
January 05, 2012

how do I tell if I have a short or long yoke? does it make a difference?

Answers

January 10, 2012
John
Part number 91048445 Yoke used in this third member carries these specifications: * Thickness of ear where u-bolts go through is .818" or 13/16" * Depth from face to bottom of u-joint cap recess is .520 or 1/2" plus * Space between ears where u-joint caps fit is 3.211" or 3-3/16" plus * Overall length is 4" * Outside diameter at seal area is 1.813" * Center to center of u-bolt holes is 1-3/8" U-joint used is common 1 1/16 diameter cap with 3 7/32” spread.
1 answers

What U-Joint is this set up for?

Kelly
Stillwater, Oklahoma
April 17, 2015

What U-Joint is this set up for?

Answers

April 17, 2015
Eric
Expert
This third member requires a 1310 series U-joint such as 91045153 which is a 1 1/16" diameter cap and 3 7/32" wide.
1 answers

What is the hp limit on this? What posi is it? Eaton?

Devan
Ohio
June 17, 2015

What is the hp limit on this? What posi is it? Eaton?

Answers

June 17, 2015
Eric
Expert
This third member uses a Motive Gear differential part number 910109028 or 910109031. It is intended for street driven applications. If you are using this in a drag race scenario especially with a trans brake it is not well suited for that application. Sorry we do not have a horsepower rating on this third member. The use of the vehicle is more of a factor than the horsepower of the engine.
Page 1 of 1

You may also be interested in:

Currie 9 Inch Ford Rear Axle Kit
(Part #91045100)
                        

Currie's Universal Hot Rod Ford 9" kit includes a brand new 56" housing, lifetime warranty 31 spline axles, new axle bearings and seals, and new style big Ford ends. 

  • Housing is 56" from axle face to axle face
  • Axles drilled for 5 x 4-1/2" Ford/Mopar and 5 x 4-3/4" Chevy/GM bolt patterns
  • Includes wheel studs, 1/2"-20 Ford and 7/16"-20 Chevy
  • 1/4" heavy duty late model large bearing style retainer plates

Note: Axle bearing does not come pressed onto the axle shaft, and wheel studs are not installed. Third member not included.

Currie Rear Axle Installation Instructions

How to Measure Your Housing Tech Tip (Link)

Need a certain length not found on our site?  Check out Currie's 9+ Rearend Calculator to have specially sized axles or rearend housings made for your specific application.  Custom orders will be built and processed directly through Currie Enterprizes and shipped to your door. For ease of ordering, please refer to Currie's Dimension Diagram

Installation Notes:

When installing new axles in rearends with posi traction differentials, be sure to install the driver's side axle first to keep the splines properly aligned.  Failure to do so may move the two splined gears out of alignment, and it may be difficult to install the driver's side axle properly if the passenger side axle is already installed.

If installation of passenger side axle is done first it may require two people when installing the driver's side axle, with both parties rotating reach axle until splines are in line and the driver's side axle fully sides into the housing.

To ensure you get the most out of your new 9 Inch components, Currie recommends that you perform a proper break-in process:

  • Use a name brand mineral-based gear oil, preferably 85w140 (Extremely high quality synthetic oils may be used once break-in process has been successfully performed)
  • Place vehicle on jack stands and let the rearend spin while the vehicle idles - run transmission in both forward and reverse periodically throughout the process
  • Continue to run the rearend until the pinion gets hot (place hand on bottom of the differential housing to verify this)
  • Proper break-in allows:
    • The ability to install new axles and hit the track the same day without worry
    • Extended life for rearend components
    • Keeps the quality and life of your gear oil

Note: If you find that your rearend is running somewhat "tight" be sure to add Currie's 9+ Friction Modifier to "loosen up".  If a more aggressive performance is desired, Friction Modifier is not needed.

 

 

Ford 9 Inch Posi Traction Third Member Assembly
(Part #91048345)
                        

If you’re looking for a complete third member for your Ford 9-inch rear end housing, but want the added performance of a limited slip differential, Speedway Motors now offers you a 9" Ford street 3rd member for your street rod. We start with reclaimed, genuine Ford 9-inch carrier housings and then clean and inspect them prior to installing all-new bearings, seals, a 1310-series yoke, and your choice of ring-and-pinion gears. The 1310-series yoke is the correct size for many Ford applications with cups 1-1/16 inch in outside diameter and a span of 3-7/32 inch across.

These Ford 9 inch third member assemblies feature a Richmond Powertrax Grip Pro differential available in 28 or 31 spline axle shaft configurations. This clutch-type differential is perfect for light-to-medium weight street vehicles where one wants posi-action and long clutch life, without the adverse handling effects or noise of a full locker. When coasting around turns, the clutches are disengaged to extend clutch life. When accelerating in a straight line on dry pavement, the clutches engage, sending equal power to both wheels for maximum traction. This makes them ideal for street use, with the occasional trip to the drag strip as well.

All third members are assembled by our team of professionals and are delivered to you in a handy plastic carrying case, for an overall value that can’t be beat

Available in your choice of 3.50, 3.70, 3.89, 4.11 or 4.56 gear ratio.

Gear lube recommendations :

  • 910-44090 - for street and every day driving under normal conditions
  • 910-44140 -  for extreme duty, towing, or very hot climates

Instructions (PDF)

Currie 9+-98126 9 Inch Ford Cut-To-Fit 31 Spline Axle, 26 Inch
(Part #91045120)
                        

These axles have 4" of spline which will allow you to cut a maximum of 3" of the spline off to obtain the correct length. This is perfect for small shops and will allow you to build your own custom width rear end easily. Axle length is measured from the flange to the end of the splines. All CTF axles come with a full installation package which includes one set of five 1/2"-20 Ford style wheel studs, one set of five 7/16"-20 Chevy style wheel studs, one set-20 tapered roller bearing with race, seal, & collar, and one heavy duty late model large bearing style retainer plate.

  • 9 Inch Ford
  • 31 Spline
  • 26 Inch Long
  • Drilled for both 5 on 4-1/2" and 5 on 4-3/4" wheel bolt patterns
  • Includes both 7/16"-20 and 1/2"-20 wheel studs
  • Compatible with "Big Ford - New Style" housing and brakes with 2-1/2" offset
  • Includes a set-20 bearing and retainer you will have to press on
  • Axles sold each, not as a pair

How to Measure Your Housing Tech Tip (Link)

Need a certain length not found on our site?  Check out Currie's 9+ Rearend Calculator to have specially sized axles or rearend housings made for your specific application.  Custom orders will be built and processed directly through Currie Enterprizes and shipped to your door. For ease of ordering, please refer to Currie's Dimension Diagram

 
New Ford 9 Inch Aluminum Carrier Housing w/3.062 Inch Caps
(Part #91048393)
                        

This brand new carrier housing is built to take street/strip abuse without the fear of breaking. Our aluminum housing has forged caps and extra beef where it's needed. Most stock differentials use the 3.062" o.d. bearings # TLM603049 w/ 1.781" i/d.

The aluminum case will save you 20 lbs. over the cast iron version. You should also add a new heavy duty aluminum pinion support while you're at it. 

Carrier caps torque to 95 ft lbs.

Speedway 9 Inch Ford Pumpkin Gasket
(Part #9192300)
                        Our reuseable rear differential gaskets have a steel core and non-stick coating. Fits 9" Ford rear axle third member housings.
                    
Universal Drive Shaft U-Bolts, 1-1/16 Inch Cap
(Part #91048319)
                        Speedway universal drive shaft U-bolts are forged steel for 50% more strength than standard units. Fits U-joints with 1-1/16" diameter caps.