3 speed or 4speed auto

les · Post by **les** » Thu Oct 18, 2007 9:12 am

Looking at putting in a auto gear box into my new 92 Brumby.Which way to go L series 3 speed or 4 speed Liberty; If i go auto will i have to change the front diff ?

Les

Matatak · Post by **Matatak** » Thu Oct 18, 2007 9:28 am

4 speed Liberty wuld be more practical to drive with (or is there an overdrive in the 3 speeds?) but also id expect will cost mroe and be more work to get it to fit.

Front diff will cange over when u do the box as they are inside. unless the Lseries autos had a 3.7 diff ratio (most probably what u have now) u will need to change the rear diff over (unless ur putting in a FWD box obviously.

plus the extra work which goes with it.

wagonist · Post by **wagonist** » Thu Oct 18, 2007 10:10 am

If you get the Liberty box, just install the matching rear diff from the same car.
They are a bolt in by using the front bracket off your existing diff.
You will need to install fully floating CV joints on both ends of your rear driveshafts (ie the ones you can push in & out, like the front inner ones)

steptoe · Post by **steptoe** » Thu Oct 18, 2007 1:42 pm

i get the idea that the 3 speed auto like in my L series is 3.45:1 diff at the front and 3.7 at the rear, sounds weird but that looks to be the case from what i have seen quoted in here and in factory manuals. Top is 1:1 ratio i think and could seriously do with an overdrive 4th gear. Has no low ratio just 1 2 3 and R.

The lib box must be like if not same as late L series 4 speed auto - needing their own ecu to run it and weigh about 110kg including the torque converter.

steve_rising_sun · Post by **steve_rising_sun** » Thu Oct 18, 2007 1:47 pm

The non turbo uses 3.7 in the front and 3.9 rear. The last Ls used the 4at trans.
Steve

les · Post by **les** » Thu Oct 18, 2007 4:56 pm

Thanks everyone for the info,somethink to think about for next year.

Les
It's good to be a junior member for someone in their late 50s.

steptoe · Post by **steptoe** » Sat Oct 20, 2007 12:12 pm

must be a reason to take a backward step from yer 5 spd dual range ?