3.27 to 4.10 speedo correction

[96_expy]

I recently put a 4.10 ring and pinion in the 8.8, changed from 3.27s. It is 4wd and i took the front driveshaft out to eliminate screwing the t-case. i'm running 32x11.50 swamper SSR's and my speedo is like 10-15 mph off. This caused me to get a $179 ticket.. I would like to know some info on what i can do to get the speedo corrected? I have the bw4405 t-case with the 4.0 and auto trans. Thanks!

 

[shadowless127]

It's computer based. A stealership can do it for you.

 

[96_expy]

ok, thanks! i will have to see how much they will wanna rip me off to do that.

 

[rwenzing]

It's computer based. A stealership can do it for you.

Speedometer error can be corrected in the 4WABS Module of your 2001 Explorer but that is not possible in the OP's 96 Ex.

I recently put a 4.10 ring and pinion in the 8.8, changed from 3.27s.... I would like to know some info on what i can do to get the speedo corrected?

95~97 Ranger/Explorer use a gear driven Signal Generator VSS that sends a square wave directly to the electric speedometer. The SG is mounted into the transmission (2WD) or transfer case (4WD) and can be accessed fairly easily under the truck.

The pulse frequency supplied by the Signal Generator and delivered to the speedometer can be adjusted via interchangeable gears similar to the way a cable driven speedometer is corrected for axle ratio or tire diameter changes. Replacement gears should be readily available but the range of adjustment is limited. Hopefully, your combination falls into that range.

Note that a gear used in the 2WD automatic transmission is different from its counterpart used in the 2WD manual even if the tooth count is the same. Unfortunately, I don't know which of these two styles is used in the transfer case of the 4x4 models - you'll need to research that before getting the gear. Before that, you'll also need to determine the tooth count of the gear currently in your Ex so you can calculate the tooth count of the gear that you'll need to substitute.

For calculations and more info on available gears, check the Speedometer Correction article in the Tech Library at www.therangerstation.com

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If you can't find the right size gear for your axle/tire combo, all is not lost. There are electronic converter boxes that can be installed in the gray/black wire leading from the Signal Generator to all of its end users (speedometer, PCM, Speed Control, Message Center, GEM, Automatic Ride Control, etc.). The converter box can correct the pulse frequency to adjust for a wide range of axle ratio and tire diameter changes. Expect to pay about $100~200 if you decide to go this route.

 

[99SportX]

You are lucky. I would go for the speedo gear option first. On the 96-97, the speedo is messed up when you change gears or tires.

On the 98-01, the sensor is in the rear axle and is only changes when the tires change. The 98-01's have to be reprogrammed through the ABS computer. You can also buy a speedo calibrator. I have a dakota digital SGI-5 on the way to calibrate my speedo for the 33" tires. It was $75 at Summit.