3.55 and 3.73 Gear Swap Opinions

Discussion of NON STOCK, NON OEM swaps, upgrades, lowering, modifications, modifying, customizing, anything Lincoln Mark VII.

3.55 and 3.73 Gear Swap Opinions

Postby BSharp1 » Thu Aug 17, 2017 9:28 pm

For those of you that have swapped 3.27 gears for either 3.55 or 3.73 with a stock or mostly stock car otherwise, what do you like or dislike? Advantages or disadvantages? Would you do it again?
90 White LSC
90 Mustang LX
95 Lightning
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Re: 3.55 and 3.73 Gear Swap Opinions

Postby CDW6212R » Thu Aug 17, 2017 9:50 pm

I have 3.73's in my stock 91 LSC, I prefer the 3.27's more. The gearing change helps from zero to the new shift point, say 35mph, but it's notably worse from that point to where it used to shift to 2nd(about 47mph). The 3.73's make it very easy to spin the tires, and it wears them out much faster.

I was testing my car a lot back then, I own a VC2000 test device, and accurate 1/4 mile device. I gained about a tenth in the 1/4 mile times. It's quicker through 1st gear, slower in 2nd to where it used to shift(still in 1st before), quicker from there to 3rd gear, slower from there to where it used to shift to 3rd etc.

The AOD trans has a low stall speed TC, that's a big negative. The Lincoln is slow from the start, go find a Fox Mustang with the AOD, and feel how it jumps at the start. Those have a better TC for performance.

I'm going back to 3.27's when I install my 347, more power will affect take off torque(tire spin). I'm changing to the 4R70W, a better trans, and with the AODE planetary(close ratio), which will maintain the AOD gearing.

I'd say work on power, and the torque converter when you can.
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: 3.55 and 3.73 Gear Swap Opinions

Postby oldschool1 » Thu Aug 17, 2017 10:35 pm

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