Drop in assembled 3rd member for 9" - Quick Performance, Speedway, or ?

[davisjstone]

Looking for some opinions.

Planning for a re-gear on the 9" to match my 4R70W with OD (fresh 351w, 33" tires). My plan is to do 4.56, upgrade to 31 because now is the time, and go with a helical gear driven limited slip like an Eaton Truetrac. With the price of labor, i'm leaning towards buying a drop in unit and putting in myself.

Quick performance has good reviews - $1500 (w/shipping): https://www.quickperformance.com/Fo...omplete-Center-Section-Third-Member_p_61.html

Also came across a drop in 9" on Speedway thats priced right $1050 (w/shipping): https://www.speedwaymotors.com/Ford...mber-Assembly,458087.html?sku=91049349-31-456

The Speedway unit comes out to be about $450 cheaper which is significant. Then again, this is a job I only want to do once. This will be a street rig. Does anyone have experience with the Speedway unit, Quick Performance, or another recommendation?

 

[nvrstuk]

@Yeller what was that manufacturer that you recommened (again)?

 

[SteveL]

Location? There may be a reputable shop local to you to save on shipping. If you only want to do it once you might want To go arb and be done with it. Then you know you won't need to upgrade.

 

[Yeller]

I really like Quick Performance. Their work is done in house and is well done. The Speedway unit makes me nervous, for the price it is too good to be true, less than the cost of the parts.

Couple of things you need to require in order of importance.

1: Daytona pinion support, 4.56 gears with OD it’s not a matter of if the pinion bearings will fail it is a matter of when, this prevents that. On the subject of pinion support, get the solid spacer, if you ever have to replace a pinion seal, you will thank yourself.
2: Make sure you get the limited slip you want, there is night and day differences in performance and strength between a True Trac and a rebuild stock Ford unit. The rebuilt unit sucks and breaks easily.
3: Doing more than leisurely Sunday drives to church? Wheeling more than a graded dirt road? Get the high strength carrier, nodular or whatever they choose to call it, sucks when your pinion spits out on the ground and rolls down the hill behind you.

For me #1 and #3 are the most important, just because I know me, I chase squirrels and next thing you know I’m breaking parts, 80% can forgo #3 they will never push their equipment. Without the ability to shock load with a clutch, they are pretty safe until you start wheeling, all it takes is a spirited moment and a bounce and pow.

 

[Shimmy]

i have a quick performance 3rd member. very very happy with it. yukon case, 4.56 motive gears, eaton trutrac.

i believe speedway uses their own cases or maybe it was gears. i also don't believe they use eaton. all these factors contribute to their more affordable pricing.

that being said i read several reviews of people having to readjust the preloads on the speedway members. i didn't read any bad reviews on quick performance.

EDIT: i waited 7-9 weeks for mine since QP had such a huge backlog of orders. When you place your order, inquire on the build time.

 

[56f100bbw]

i have a quick performance 3rd member. very very happy with it. yukon case, 4.56 gears, trutrac.

i believe speedway uses their own cases or maybe it was gears. i also don't believe they use eaton. all these factors contribute to their more affordable pricing.

that being said i read several reviews of people having to readjust the preloads on the speedway members. i didn't read any bad reviews on quick performance.

I like dealing with quick performance they built me a 9 inch rear end housing for my 65 fastback I also thought shipping cost were very reasonable

 

[toddz69]

I bought a Quick Performance unit (nodular housing, TrueTrac, 4.56) about a year ago and it's still sitting in my garage waiting to be installed. Yeller's recommendation and I'm impressed with what I see. I also learned that shoving the 3rd member in a 5 gallon bucket is a pretty good way to ship such a thing!

Todd Z.

 

[Shimmy]

I bought a Quick Performance unit (nodular housing, TrueTrac, 4.56) about a year ago and it's still sitting in my garage waiting to be installed. Yeller's recommendation and I'm impressed with what I see. I also learned that shoving the 3rd member in a 5 gallon bucket is a pretty good way to ship such a thing!

Todd Z.

lol agree! the bucket shipping method is genius!

 

[davisjstone]

Sounds like lots of good feedback for Quick Performance, the Speedway seems unknown.

The speedway listing says its nodular case, uses “Daytona" style pinion bearing support, and solid spacers. Seems like all the right buzz words, but as @Yeller mentioned, almost seems too good to be true. Also makes me a bit nervous that it seems to be a unknown brand helical style diff as opposed to a well known truetrac.

Since I'll be getting a new pumpkin and axles, should I go with 35 spline, or is 31 spine the right choice? Darn project creep.

 

[nvrstuk]

What everyone said...

I have grenaded all those parts that Yeller discussed in points #1 & 3 & know many others that have also so make sure (your call) you only have to do this once!

 

[DirtDonk]

As far as spline count, that depends on you.
Those 31 spilnes are more than strong enough for normal street use, and normal off roading, with normal tires. Meaning up to 36 should be no problem.
But now it comes down to you.
How do you drive? How much power are you putting down there to the differential?
Do you drive gently, or do you like to pull into the Ice Cream store parking lot with your kids and light up the tires going around corners to give them (and you) a thrill?
Do you plan to take it Off Road and do some hard rock crawling? if so, when you’re off road, do you like to push the skinny pedal to do burnouts in the dirt or blast up a rock face?
Depends on how it’s used.

Coming down to the bottom line though, do you even need a limited slip for the street?
No, you really don’t 999 times out of 1,000.
In fact, it’s often a detriment rather than a benefit.
Hell, under the circumstances you describe (street driving), stock axles with an open differential wouldn’t be a problem. As they haven’t been a problem for most of us.
Again, unless you have that heavy right foot previously mentioned.

 

[JB Fab]

Everything Yeller said is 'spot-on'.

I have used Dutchman axle for anything I didn't rebuild myself, and they all been 100%.

 

[skrit]

I bought this one from eBay with free shipping.... it was $971.00 and it was delivered in 6 days!

 

[Shimmy]

I bought this one from eBay with free shipping.... it was $971.00 and it was delivered in 6 days!

View attachment 934654

clutch style vs helical gear limited slip. did yours include a yoke? i recall seeing this ad and it didnt

 

[skrit]

I just went with clutch track-loc and bought a yukon yoke. I have a selectable OX locker in the front. I believe this setup will be the best for my application.

 

[ba123]

I got axles from Dutchman and considered getting a whole 3rd member from them, That's where WH gets their stuff as well last I checked.

Axles were really nice and done custom exactly how I asked.

 

[Doyle]

Since I'll be getting a new pumpkin and axles, should I go with 35 spline, or is 31 spine the right choice? Darn project creep.

When I did mine there was only a $100 difference between the 31 and 35 spline packages, no brainer for me.