Jump to content
Ultimate Subaru Message Board

Possible to swap FWD auto trans into AWD Legacy?


Recommended Posts

Is it possible to swap an auto FWD trans into an AWD vehicle? My buddy lives in Georgia and would rather not have AWD. Was wondering if this could be as simple as swapping trans or swapping trans and TCU? (don't care about the rear components, that's all easy).

Link to comment
Share on other sites

To get this back on-topic...

 

... no practical experience yet, but I can't see why not. Probably need a TCU swap unless the TCU has a pin for FWD/AWD determination (my FSM is packed away at the moment so I can't look at TCU specs). Probably need tranny mount, too.

Link to comment
Share on other sites

i never mentioned gas mileage. this has nothing to do with gas mileage. for the record, the rear bits are easy to remove. the entire cross member, rear diff and driveshaft can be lying on the ground by removing less than 10 bolts, it's very easy.

 

To get this back on-topic...

 

... no practical experience yet, but I can't see why not. Probably need a TCU swap unless the TCU has a pin for FWD/AWD determination (my FSM is packed away at the moment so I can't look at TCU specs). Probably need tranny mount, too.

that's what i'm wondering, if the TCU's, like the ECU's are interchangeable? but if that's not the case i'd still need the wiring to be compatible between the two. i may swap in a FWD TCU in one of my AWD vehicles and see what happens just for giggles. i have a 1997 impreza OBS FSM, hopefully i can find it (it's on CD and i just moved) and compare the wiring diagrams.
Link to comment
Share on other sites

I don't believe there is any pin identifying whether the TCU is for AWD or FWD. So I sort of believe you'll need a different TCU.

 

I do believe I still have my FWD TCU off my 90 Legacy if interested. You will also need to swap the trans mount as well. Again, I've got a brand new FWD auto trans mount I was going to put in, but never did, so if interested, I've got that too.

 

Just let me know

 

Also, if interested, here's TCU I-O

http://main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/TCU_I-O_page1.jpg

http://main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/TCU_I-O_page2.jpg

Link to comment
Share on other sites

thanks for the TCU input-output Josh. is that for 1999 model years?

 

i'd likely stick to a FWD 1999 trans to make sure there's no surprises. it's up to my friend, since it's his car. but i'll be doing the work so want to make sure it's possible. for now i think he's staying AWD though. but i'll keep the mount in mind if he changes his mind. thanks for the wiring info, awesome!

 

from those diagrams it doesn't appear the electronics is really much different at all? it doesn't differentiate between FWD and AWD?

was that just for the AWD or FWD or is that for both like i think it is?

thanks!

Link to comment
Share on other sites

I wasn't aware that Subaru made a FWD vehicle later than 1996 ( ??? somewhere in the mid 90's ??? ). Thought in 1996 they were AWD ONLY. So you would have to swap the older 4EAT into a newer vehicle.

 

Anything could be done, for given the time and cost.

Link to comment
Share on other sites

Easier and cheaper to swap nameplate - Honda, Toyota, etc.You'd be spending money to make a car virtually unsalable. Doesn't make sense even to a Georgian.
you could ask questions rather than assume you're right, in this case you are wrong. good luck finding a similar late model, low mileage honda/toyota FWD for $1,000 in excellent condition. i am not versed enough in those makes to do that, with Subaru's i can. i'm not looking for something "salable", i'm trying to help out a friend and he doesn't want to deal with torque bind, towing issues, matching tires and will never need AWD.

 

I wasn't aware that Subaru made a FWD vehicle later than 1996 ( ??? somewhere in the mid 90's ??? ). Thought in 1996 they were AWD ONLY
i didn't know that. is that true, all 1996 and up auto's are AWD only?
Link to comment
Share on other sites

This whole topic probably makes sense only as a mental exercise, but technically, there should be a way to eliminate AWD. The rear diff. can stay in place and only the axles removed, except that outer CV joints should be taken apart and their housings with splined ends and nuts kept in place, because that's what holds the bearings together. Same can be done with inner joints to keep the diff sealed, or one can cover the axle bores with homemade sheetmetal covers sandwiched under the bearing retainer flanges. The driveshaft woud have to be disconnected and removed, or held securely out of the way. The control unit would have to be swapped as already noted.

Link to comment
Share on other sites

Well, if the idea was to save fuel then rear diff. needs to be looked at as well. But all this is strictly hypothetical.

As for the trans, you can remove the extension housing, and the transfer gear on the trans. side from the output shaft, then install a cover from a FWD version. Did I say it's hypothetical?

Link to comment
Share on other sites

you could ask questions rather than assume you're right, in this case you are wrong. good luck finding a similar late model, low mileage honda/toyota FWD for $1,000 in excellent condition. i am not versed enough in those makes to do that, with Subaru's i can. i'm not looking for something "salable", i'm trying to help out a friend and he doesn't want to deal with torque bind, towing issues, matching tires and will never need AWD.

 

i didn't know that. is that true, all 1996 and up auto's are AWD only?

Exactly what vehicle are you trying to convert? A legacy in good condition is worth more than $1,000, I'd hope. The certainly sell for more than that around here.

 

If he has an AWD model with 4EAT, he can "convert" it to FWD by putting a fuse in the FWD plug under the hood.

Link to comment
Share on other sites

Well, if the idea was to save fuel
nope, that's not the idea. there are plenty of threads about that already, i wouldn't need to start another!
Exactly what vehicle are you trying to convert? A legacy in good condition is worth more than $1,000, I'd hope. The certainly sell for more than that around here.
typically far more than $1,000. thank you, that's exactly my point!!!!!!!!!

copy that, good point to remember the FWD fuse is always there for towing, mismatched tires, etc.

1997 ALL Subaru's are AWD ONLY ...... Read down in the following link ....

excellent, good to know. with the trans changes in 99, that complicates things.

Link to comment
Share on other sites

thanks for the TCU input-output Josh. is that for 1999 model years?

 

i'd likely stick to a FWD 1999 trans to make sure there's no surprises. it's up to my friend, since it's his car. but i'll be doing the work so want to make sure it's possible. for now i think he's staying AWD though. but i'll keep the mount in mind if he changes his mind. thanks for the wiring info, awesome!

 

from those diagrams it doesn't appear the electronics is really much different at all? it doesn't differentiate between FWD and AWD?

was that just for the AWD or FWD or is that for both like i think it is?

thanks!

 

No that diagram is for a 90 Legacy

 

The I/O is for the AWD cars.

Link to comment
Share on other sites

nope, that's not the idea. there are plenty of threads about that already, i wouldn't need to start another!

typically far more than $1,000. thank you, that's exactly my point!!!!!!!!!

copy that, good point to remember the FWD fuse is always there for towing, mismatched tires, etc.

 

excellent, good to know. with the trans changes in 99, that complicates things.

 

1998 legacy had a FWD transmission.

 

InvLogo.jpgTransmission

 

A.T., FWD (ID# TA102AACAA)

A.T., AWD, 2.2L

M.T., GT

M.T., Outback

A.T., AWD, 2.5L, GT

A.T., AWD, 2.5L, Outback and SUS

M.T., exc. GT and Outback

 

but my understandig was , and this is based on logic as much as any thing, that the transmissions were the same for fwd vs. awd, just the rear extention housing was different. were all jdm trannys awd?

 

the wiring harness is different 98 vs. 99.

 

easy solution is to pull the drive shaft and "cap" the output from the tranny, then swap the rear end. or just remove the rear section of the drive shaft and leave every thing else.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...