Torsen Front Differential Upgrade - What's Needed?

[Surfnbike]

I'm planning on regearing my 2020 F150 3.5L EB (stock 3.55 gears) as soon as next week when I throw some 35" Raptor takeoffs on it. While I have the front diff open I figure I may as well throw a Torsen in it like some Tremors/Raptors have from the factory.

I couldn't find out if my local shop to tell me if they have done this before as they mostly work on Jeeps. What do I need besides the Torsen diff? I heard that some of the assembly bolts are not reusable, and something about friction modifier being required by Ford? I would appreciate some info from anyone with some experience on this. Since our trucks don't have front selectable lockers I'd really like to get this in there. I do a lot of heavy offroading so it would be worthwhile for me to have better traction up front.

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[Cartoon_209]

I’m here as well because I have a lariat 4x4 with 4a but I was wondering if it’s worth the upgrade as well.

 

[ThumperF150]

2024 RCSB 4x4. I added Torsen LSD, Tremor front axle shafts, 4.11 gears (from 3.73s), custom diff cover with drain plug and 35” tires.

The gear kit came with everything needed for the gear and diff swap. The swap is a lot of work for a shop as they need to drop the diff and steering.

I’ve read about friction modifiers and bottom line from what I’ve read, it does not really matter. But that’s Google info. I’m no expert.

Only regret is that I found out after the fact, a bitchen Raptor aluminum front diff cover with drain plug would have bolted right on.

You will also need Forscan or a Hypertech module to get your speedometer correct.

 

[Surfnbike]

Thanks for the info. What is the benefit of the Tremor half shafts?

My truck is a 2020 and these half shafts are listed as for 2021-2023 model years only:
https://performanceparts.ford.com/part/M-3429-F150

Is this is Torsen you bought?
https://performanceparts.ford.com/part/M-4204-F150LS

Does anyone know what the part # is for some 4.30 gears from Ford? I have the max trailer tow package if that matters--I think it came with a bigger rear end? Or is it just the regular super 8.8 and any Ford 4.30 gearset work?

When adding 35s in my old 2018 F150 I had 3.73s and went up three steps to 4.56 gears. So I'm thinking 4.30s would be good for the 3.5L EB with 3.55 gears but would appreciate any feedback from anyone else who has regeared.

 

[ThumperF150]

Thanks for the info. What is the benefit of the Tremor half shafts?

My truck is a 2020 and these half shafts are listed as for 2021-2023 model years only:
https://performanceparts.ford.com/part/M-3429-F150

Is this is Torsen you bought?
https://performanceparts.ford.com/part/M-4204-F150LS

Does anyone know what the part # is for some 4.30 gears from Ford? I have the max trailer tow package if that matters--I think it came with a bigger rear end? Or is it just the regular super 8.8 and any Ford 4.30 gearset work?

When adding 35s in my old 2018 F150 I had 3.73s and went up three steps to 4.56 gears. So I'm thinking 4.30s would be good for the 3.5L EB with 3.55 gears but would appreciate any feedback from anyone else who has regeared.

Tremor shafts are stronger with Raptor CVs and thick/stronger boots. Plus they come painted, not pre rusted like the originals. They only work with electric IWE hubs, If your hubs are vacuum activated, they will not work.

Yes that is the same diff I used.

My truck came with 31s so going up to 35s was about a 10% increase. I wanted to go about 10% lower on my gearing to keep everything stockish. 4.21s would have been perfect so I went 4.11s. My goal was to keep my cruising rpm as close to factory as possible. I’m within about 100 rpm from stock.

 

[Surfnbike]

Do anyone know if those half shafts will work in a 2020 F150? Ford shows them for 2021+.

 

[TTruk24]

2024 RCSB 4x4. I added Torsen LSD, Tremor front axle shafts, 4.11 gears (from 3.73s), custom diff cover with drain plug and 35” tires.

The gear kit came with everything needed for the gear and diff swap. The swap is a lot of work for a shop as they need to drop the diff and steering.

I’ve read about friction modifiers and bottom line from what I’ve read, it does not really matter. But that’s Google info. I’m no expert.

Only regret is that I found out after the fact, a bitchen Raptor aluminum front diff cover with drain plug would have bolted right on.

You will also need Forscan or a Hypertech module to get your speedometer correct.

I just put the Torsen and ford OEM 4.10 differentials on my truck, did you do anything to get rid of the U0422 error on the PCM saying that your axle ratio is out of specification? I already programmed the bdycm and had no trouble at all there.

 

[ThumperF150]

Never got that code. Never got any codes. But I changed BOTH diffs from 3.73s to 4.11s and installed 35s all at the same time.

 

[TTruk24]

Never got that code. Never got any codes. But I changed BOTH diffs from 3.73s to 4.11s and installed 35s all at the same time.

Weird. Did you change the body control module to the new gears and wheel diameters when you did yours?

 

[ThumperF150]

Weird. Did you change the body control module to the new gears and wheel diameters when you did yours?

No. I did not mess w ForScan at all.

My speedo was off so I used a Hypertech Speedometer Module to correct that.

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