2001 Forester Auto transmission into 1990 Liberty ???

Liberty Valance · Post by **Liberty Valance** » Tue Jun 04, 2013 5:40 pm

I have been having difficulties finding a replacement Auto transmission for my 1990 Liberty. A nice low km wrecked 2001 Forester has presented itself to me with the opportunity to purchase to Auto, TCU and rear diff.

This sounds appealing as the 4.11 final drive ratio on the Liberty struggles with the big 27" tyres. The 3.9 forester ratio would be much better and I understand the transmission is generally tougher all round than the older Liberty unit.

So I want to ask the forum community is this conversion possible and what should I look out for?

Gannon · Post by **Gannon** » Tue Jun 04, 2013 5:57 pm

The transmission will fit mechanically, but electrically they are quite different. The sensors and valvebody are quite different and the TCU and ECU talk to each other in post 1998 models (identified by a round oil filter on the passenger side of the transmission).

More hassle than its worth really. If you found a transmission from a pre 1998 liberty/outback or even impreza (as long as it doesnt have an external oil filter) you should be sweet.

Liberty Valance · Post by **Liberty Valance** » Tue Jun 04, 2013 6:15 pm

Gannon wrote: If you found a transmission from a pre 1998 liberty/outback or even impreza (as long as it doesnt have an external oil filter) you should be sweet.

Great info thanks. So the models you mentioned all have 3.9 final drive ratio and are essentially 'plug-and-play' with respect to TCU?

Liberty Valance · Post by **Liberty Valance** » Tue Jun 04, 2013 6:32 pm

Hang on, I have stuffed up here haven't I?
I should be looking for a 4.44 final drive to compensate for the big tyres, shouldn't I ???

niterida · Post by **niterida** » Tue Jun 04, 2013 6:41 pm

Yepif you want to lower the ratio to make it rev higher for the same speed youneed a higher numericalk diff - so yes 4.44.

Gannon · Post by **Gannon** » Tue Jun 04, 2013 7:17 pm

I think Gen2 Outback (94-98 ) have a 4.11 final drive and should be compatible with your car.

vincentvega · Post by **vincentvega** » Tue Jun 04, 2013 10:44 pm

im not sure its that simple though. is a 4.44 auto necessarily geared lower than a 4.11 auto? Depends what the gear ratios are internally.

My solution was to put a 4.44 diff on the front of a 4.11 box. Made 27" tyres feel normal.

PM subaman (Grant) i know he has a good GX auto he wants to sell.

Liberty Valance · Post by **Liberty Valance** » Wed Jul 17, 2013 9:44 am

Gannon wrote: If you found a transmission from a pre 1998 liberty/outback or even impreza (as long as it doesnt have an external oil filter) you should be sweet.

Hi Gannon,

I have been offered a 95 Outback auto transmission but the drive shafts look different to the Liberty where they enter the transmission. (ie. push in rather than slide on to the splines)

Would it be simple enough to also use the Outback driveshafts in my Liberty?

Also, would I need to run the Transmission Computer from the Outback?

Thanks, Scott

Gannon · Post by **Gannon** » Wed Jul 17, 2013 6:34 pm

Being an outback it could possibly be a different ratio so the rear diff will have to be changed too. And because outbacks had taller tyres, so the speedo will be slightly out. You might get away without needing to change the tcu. I think you could just change the inner cups to change from female to male joints

niterida · Post by **niterida** » Wed Jul 17, 2013 7:48 pm

vincentvega wrote:im not sure its that simple though. is a 4.44 auto necessarily geared lower than a 4.11 auto? Depends what the gear ratios are internally.

My solution was to put a 4.44 diff on the front of a 4.11 box. Made 27" tyres feel normal.

PM subaman (Grant) i know he has a good GX auto he wants to sell.

AFAIK all the 4spd autos have the same internal ratios.

Gannon wrote:Being an outback it could possibly be a different ratio so the rear diff will have to be changed too. And because outbacks had taller tyres, so the speedo will be slightly out. You might get away without needing to change the tcu. I think you could just change the inner cups to change from female to male joints

Also AFAIK all Outbacks have 4.44 diffs.

So you will have to change rear diff to 4.44

vincentvega · Post by **vincentvega** » Wed Jul 17, 2013 8:27 pm

I have since come to the same realisation about the internal ratios. I went to a lot of trouble to build my box. I should have just fitted outback speedo gears to a gen2 TT legacy box.

niterida · Post by **niterida** » Wed Jul 17, 2013 8:40 pm

Yeah and if you are going to the trouble of fitting a different box you should try andf get a WRX or Gen 2 Twin Turbo box - they have VTD centre diff which is 1000 times better than standard

Liberty Valance · Post by **Liberty Valance** » Thu Jul 18, 2013 7:02 am

This is all too hard. One bloke swears a 95 Outback Auto will slip straight into my Liberty but then the crowd claims that I will also need to change drive shafts, rear diff and TCU.

Honestly I just want the car driveable, I do 90 kilometers per day on the highway and occasionally drive it on the beach. If I could just find a straight replacement transmission I would have it in the car tomorrow.

ktm300 · Post by **ktm300** » Thu Jul 18, 2013 7:32 am

Mate,
I think you need to take a teaspoon of cement and HTFU.
or
Maybe you should give up offroading, buy a Hyundai and play Golf.

vincentvega · Post by **vincentvega** » Thu Jul 18, 2013 7:48 am

Did you try my original suggestion and pm subaman?

Alternatively i reckon the outnack box will be ok with your original tcu as it isnt vtd. You will need a 4.44 rear diff to go with it. Doesnt havd to be the one from the outback. A gen1 turbo auto rear diff will drop straight in and is a viscous lsd.

Best thing i ever did was switch to 4.44 it made a huge improvent in all areas.

ktm300 · Post by **ktm300** » Thu Jul 18, 2013 8:13 am

I could not agree more. Everyone worries about big tyres and lift kits, more power, loud exhuasts and flashing lights.

Getting the correct Final drive gearing is one of the best mods you can do, it makes all the other mods you do work as they should, but unfortunelty you cannot see it or hear it, so not many do it.

Liberty Valance · Post by **Liberty Valance** » Thu Jul 18, 2013 11:27 am

vincentvega wrote:Did you try my original suggestion and pm subaman?

Yes thanks, the PM didn’t work but I found his number and called him this morning. I will be picking up a stock standand transmission this weekend.

Liberty Valance · Post by **Liberty Valance** » Thu Jul 18, 2013 11:30 am

ktm300 wrote:Mate,
I think you need to take a teaspoon of cement and HTFU.
or
Maybe you should give up offroading, buy a Hyundai and play Golf.

Good wan. Now FOB.

vincentvega · Post by **vincentvega** » Thu Jul 18, 2013 1:05 pm

that wasnt so hard then was it

subaman owes me a beer..

Liberty Valance · Post by **Liberty Valance** » Thu Jul 18, 2013 1:46 pm

Yes not too hard at all but ktm300 is still unhappy that I haven't corrected my gear ratios to compensate for bigger tyres. I guess there comes a point where I'd rather spend Weekends at the beach with my family in a nearly great Subaru then spending weekends in the garage working under a perfect subaru.