Driveshaft

[legacyB4RSK]

Getting my 2001 Legacy converted to a 5 speed from automatic for my '06 WRX swap. So far the '06 WRX diff is installed and the '06 5 speed transmission. What driveshaft would be needed as the one from the '06 WRX is too short. Would from a 5 speed Legacy do the trick or is it too week for the increased HP. Would one from a 2004 Turbo Baja be appropriate?


Thanks

[chuckthefuk]

If I am not mistaken all drive shafts are built the same. They usually do not fail and are very reliable.

Taken from NASIOC...

"Because of the Legacy's longer wheelbase the Legacy auto driveshafts are the same as the manual Impreza driveshafts.

Spline counts on driveshafts and axles are all the same, as far as I know."

That being said a 5MT drive shaft from any 5MT legacy should fit. Since a 5MT legacy drive shaft is much longer then 5MT impreza drive shaft.

Good luck with the swap.
-Chuck

[ouch1011]

Which half of the driveshaft is too short? Keep in mind that you can separate at the carrier bearing and mix and match if needed. I think that if you use the front section of the driveshaft of the WRX and the rear half of your Legacy driveshaft, that should work.

[legacyB4RSK]

Thanks for the info, I'm Confused about the diffs, I keep
reading that Subaru has front , center an rear
diffs. Of course the rear is pretty obvious but the front and center are
not, I read that when switching to a wrx gear box the diff needs to be wrx as well so that the front and rear wheels don't spin at different speeds. Does that apply to the front and center diff or are those part of the transmission? I'm not the one doing the swap, I just simply
want to understand, it's my nature


Thanks

[chuckthefuk]

Front diff = front axles
Center diff = where the drive shaft connects to the rear of the transmission.
Rear diff = rear axles

Location of center diff = #29
http://img236.imageshack.us/img236/8906/difflq3.jpg

More information about center diff remove/install
http://www.subaruforester.org/vbulletin ... hem-46979/ (http://www.subaruforester.org/vbulletin/f89/center-diffs-how-replace-them-46979/)

The entire idea about matching parts so that everything will work in proper rotation all comes down to Final Drive or FD. Example

1) WRX = 3.90 FD
2) BG Outback = 4.44
3) BD/BK GT = 4.11
etc.. etc...

The lower the final drive the longer it takes to accelerate. This is why most auto-x guys prefer higher FD like a 4.44 to get up to speed quickly. Compared to rally/mud guys who run FD lower then 3.90.

So in your case with a WRX swap this means that you must have a :

1) Front diff set @ 3.90
2) Center diff set @ 1:1 (for every input the exact output will be delivered)
3) Rear diff set @ 3.90

Center diffs can have different rations. Example if you run a 3.90 front diff with a 4.11 rear diff you will need some sort of center diff with a ration of 1.1:1 or some sort of mathematical equation to get the proper step-up to match the rear diff.

Hope this helps.
-Chuck

[legacyB4RSK]

Great info! Thanks