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Which rear diff do you get with 3.73 gears

tony72cutlass's'

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Just wanted to throw this information out there. Ordered a ‘21 super cab with 3.73 locking rear gears. I always wondered if it would be the 8.8 or 9.75 rear end. I did not order any sort of heavy duty towing package.

Turns out it’s indeed the 9.75 per the picture I took underneath today.


Ford F-150 Which rear diff do you get with 3.73 gears C40697B2-261B-4402-860A-8C56DE55085C
Ford F-150 Which rear diff do you get with 3.73 gears 5EADDD62-CBDB-44C8-ADB9-6249574C1DDC
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Nevadajack

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What engine? What is your payload?
Thanks
 

SRHAGEN

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My 2016 xl SC sport 4x4 5.0 with 3.73 was 8.8in. My 22 XLT SC sport 4x4 5.0 is 9.75 and I didn’t order the max or HD either. I was shocked, I assumed I’d get the light duty suspension like my 16 XL. My rear end on the 22 is up 6 in. higher than the front And the rear brake rotor is huge. Seems they have reduced the variable options on 1/2 ton trucks. If I wanted the HD or max tow I would have ordered it. I’m curious what comes on the RCSB 5.0 trucks.
 
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Pedaldude

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I was told that the 3.73 gears force the 9.75" in all configurations.

There are two different 9.75" axle housings, one for Max Tow and HDPP trucks and the lighter duty axle housing for other trucks.

I think that the Powerboost trucks also get the 9.75" but I don't know if all get the HD axle or not.

I also don't know if they all have the bigger brakes or not but I know the Max tow/Heavy Duty Payload Package trucks won't fit 17" wheels because of the larger diameter brake discs.
 

SRHAGEN

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My guess you get what’s on hand. That’s total speculation.
I find it hard to believe there is a conciouse determination made by gas tank, engine and gearing order That triggers the build. It maybe IDK. But my rear leafspring bottom leaf is 1.1/2 in thick also.
My 16 had light duty leafs, it would drop an inch with 500 lbs of tongue weight.

I ain’t complaining just wasn’t what I expected. the new truck rides super smooth. Just gotta get a longer hitch drop.
 

SRHAGEN

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I was told that the 3.73 gears force the 9.75" in all configurations.

There are two different 9.75" axle housings, one for Max Tow and HDPP trucks and the lighter duty axle housing for other trucks.

I think that the Powerboost trucks also get the 9.75" but I don't know if all get the HD axle or not.

I also don't know if they all have the bigger brakes or not but I know the Max tow/Heavy Duty Payload Package trucks won't fit 17" wheels because of the larger diameter brake discs.
you are correct about 3 different rear end config’s. I was looking at a order info on a granger post At there site. I saw three rearends listed somehow coded to options.
 

hotrodmex

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I think that the Powerboost trucks also get the 9.75" but I don't know if all get the HD axle or not.
Finally saw someone on another board who had a 21 PB with the standard 9.75 axle. He shared a picture of the end of the axle shaft with the wheel off, looking for the broken bolt the MaxTow guys are having with the HD axle. It was a normal axle, no 3-piece / 3/4 float.

I think this was a myth born of looking at GVWRs and hopium.
 

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Where are these reports of broken axle bolts?

On the PB trucks, I believe that you get a higher payload when the HD axle is not equipped.

Same thing with the regular configuration trucks, where depending on the other equipment; you usually get the higher payload with the 8.8" axle housing. Unless you get the other equipment, you're just increasing the weight of your truck.
 
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tony72cutlass's'

tony72cutlass's'

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I remember seeing a thread earlier where someone was holding a broken bolt but I can’t seem to find it now

looked like it had sheared off
 
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tony72cutlass's'

tony72cutlass's'

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Hope so! Ordered RCSB with 5.0 and 3.73 gears, thinking I would get the beefier rear.
Yup that’s exactly what I did, it wasn’t super clear in the ordering manual and the sales guy didn’t know, but I’m happy It worked out with the 9.75, and even though it’s heavier my payload is still 1998 lb, yours should be even more if you have the RCSB!
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