Auto Transmission Swap: 3 Speed For 4 Speed Od?

March 1, 2014

Have a 1991 Toyota Corolla Wagon with the 4A-FE 1600 motor with a automatic 3 speed tranny.

Automatic Trany just broke, makes a gear grinding/retching nose, we first thought it was the flywheel/flex plate BUT relished that was wrong as starter works fine and can start car with no problems… and found fluid smells burned..

Car barely has Any trany engagement and after a couple of seconds will not move car..just makes noise..

So sound common??

OK Now comes the tricky stuff: As I have to replace the trany, A) any chance a 4 speed (3 speed with Over Drive) will FIT??

If so will I need any other major parts like the PCM?? Wiring hardness? Or like my swapping the dash cluster for one with a Tach (original had no tach) work like that swap and simply plug in and worsk just fine?

IF so any how to do threads/instructions?

More tricky stuff: Is a four speed automatic just a 3 speed with one more gear or did/do the four speed have different gear ratios, IE a lower 1^st, 2^nd, 3^rd with the OD/4^th gear not being all that much taller than the final gear ratio of the 3 speed??

Most OD tranys I have seen (Chevy van, Ford CV) the 4th gear IS a full another gear step up with an almost full gear up drop in RPM, engine noise, and even better MPG?

I ask as I have found with smaller cars the 4 speed tranys can be less a gear step up than say a Ford 4 speed..

So bottom line can it be done reasonable and is it worth the extra work?

Car already has a so called 40,000 mile Japan motor 5 years ago and has about 25,000 more miles on it, and we JUST replaced the timing belt, water pump with all front seals and motor mounts last month and a inner tie rod with new boots on rack and pinon gear box...so am deeply into car and wife LOVES it...so onward we go.

Car currently gets 25 MPG city and has done 35/40 highway MPG...rest of car holding up fairly well.

Sorry if this is a common thread, I did not find it and have little time to make up my mind...

Thanks for helping.

Rich

March 2, 2014

Can someone tell me the rpm of a 4 gear car at 70MPH??

I see 50+ hits…so someone please answer me..this is going to cost around $1000.00+ to do so I would like to get it right..

Another question is what luck have you had with used junk yard tranys VS rebuilt ones…

Rich

March 5, 2014

Thanks for nothing.

I found the answer elsewhere.

Normally I would share this info but as no one offered to help..find it yourself.

Rich

March 5, 2014

That's what I like to see, community spirit, Joy

March 5, 2014

My feelings as well, remember you were the one with the wise cracks...

Rich

March 5, 2014

Maybe if you ask these questions in an American forum you will get a better response as we don't know the vehicle you own and struggle with your terminology...

Ask your questions here, hopefully they may be better informed:

http://www.toyotanation.com/forum/91-usa/