E83 speedometer swap

[TimHixson]

I recently purchased a 2006 X3 from an auction with the front differential totally trashed. I picked up one from the local u-pull yard out of an 07. Did not realize the gears are different. I have now gone back and picked up the rear differential as well. Each part was $75 so this was the most cost effective route. I am curious where the speedometer gets its signal? Do I need the sensor out of the 07 transmission, or is this a setting in the computer?

Tim

[TimHixson]

After another bit of searching it appears the speedometer reads from the right rear wheel sensor. If this is correct then I might be fine. any thoughts here?

Tim

[dukedkt442]

Speedometer receives its signal from one of the rear wheel speed sensors so that shouldn’t be an issue.

The rear propellor shaft changed along with the drivetrain in 2007, so IIRC you’ll need one of those as well. The shaft varies in length not only by year but also transmission type. Two different length front propellor shafts were used so verify the total length of yours vs the donor car’s. If the front differential is trashed, assume your shafts are as well. Check REALOEM with both VINs to verify shaft lengths.

You’re moving from a 3.64 final drive ratio to a 3.73, so the vehicle will be quicker off the line but the engine revving faster at Highway speed.

With the differential out, replace every bushing back there.

[TimHixson]

Speedometer receives its signal from one of the rear wheel speed sensors so that shouldn’t be an issue.

The rear propellor shaft changed along with the drivetrain in 2007, so IIRC you’ll need one of those as well. The shaft varies in length not only by year but also transmission type. Two different length front propellor shafts were used so verify the total length of yours vs the donor car’s. If the front differential is trashed, assume your shafts are as well. Check REALOEM with both VINs to verify shaft lengths.

You’re moving from a 3.64 final drive ratio to a 3.73, so the vehicle will be quicker off the line but the engine revving faster at Highway speed.

With the differential out, replace every bushing back there.

Yes I actually grabbed the transfer case first before I realized it was the front dif. I had to swap out the rearward output shaft thing from the transfer case. It was just a retaining clip so that was simple. It already has both new driveshafts in it prior to me getting it. (they have paint marks of 7/21 on them) The front shaft bolted right up. I will verify the shaft lengths as you suggested. I have the VIN from the donor car. As long as the rear diff is the same connection I should be good, otherwise ill head back and get the driveshaft from the donor.

Thanks for the advise!

Tim

[TimHixson]

I looked it up. The front driveshafts are identical. The rear ones are different. Mine is 1277mm and the 07 is 1283mm. Not a huge difference, but I am real close to the u-pull yard so I will grab the correct one.

Thanks again!

Tim

[dukedkt442]

I looked it up. The front driveshafts are identical. The rear ones are different. Mine is 1277mm and the 07 is 1283mm. Not a huge difference, but I am real close to the u-pull yard so I will grab the correct one.

Thanks again!

Tim

Take some measurements: I don’t know if the difference was made on the transmission side or the differential side, or both. The aft u-joint changed with the drivetrain refresh in 2007 and off the top of my head I can’t remember if the joint’s cup size changed. I have that information compiled somewhere when I had a custom rear shaft made for my ‘08; I’ll search for it and post it here.


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