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Swapping 3.55 locker for 3.73 locker?

ARegularJoe

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Feb 2 Order: 22 Lariat 500A/3.5 EB/FX4/Max Tow/+
Will happen soon enough. I formerly sweet My21/22 will end up bound for the salvage yard and one could avail themselves of a 3.73 locker to replace a 3.55 rear. Anyone think of any issues or gotchas doing this on an FX4 Short of recalibrating the Speedo?

Beneifits?
Drawback?
OMGs?
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tony72cutlass's'

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Totally uninformed question but I wonder if the transfer cases are geared differently for the different rear end ratios.

I could also not be understanding the principle properly
 

Rockman5159

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I'm pretty sure you'll have to swap out front Diff gears as well. My 2020 had 3:55. I ordered a 2021 with 3:73 and I love it. I MPGs not even noticable between 3:55 and 3:73 for me anyways
 

Bryan Simon

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Totally uninformed question but I wonder if the transfer cases are geared differently for the different rear end ratios.
I have not really looked at my Ford, but all of f my GM had the speedo driven by the rear of the transfer case.
Transfer case does not even care what the rear and front differential ratios other than wanting them both to be the same.
If front and rear are not the same, bad things will happen to something eventually. Probably sooner than later.
 
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ARegularJoe

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Feb 2 Order: 22 Lariat 500A/3.5 EB/FX4/Max Tow/+
Thoug I've not proven it out, you can order a 373 separate on some models. If you can do this on 4x4 model, and doing so on a 2x4 model resilts in the same price change, i doubt they are done in pairs.

Additionally speedo impacts are fixed electronically. No gear set changes required.
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