RWD transmission options

[Bavario]

I'm trying to find the best manual transmission for my swap (BHW into a 1973 BMW Bavaria). Plans for the engine are balance shaft delete, replace cam (Colt likely), followers, head studs, and +1 tune (Kerma likely). Horsepower will be around 180-200 with around 300-325 torque. The transmission not only has to be able to handle the torque, but also fit in the tunnel and come close to matching the shifter location. The Bavaria left the factory with an automatic, so the tunnel is a little roomier than the manual 4 speed option.
The two main criteria for me after strength is bulk and shifter location. I'd like to buy an adapter plate that's readily available (TDI Conversions, eg). I plan on driving the car pretty regularly and getting close 40mpg. It'll still be only rwd. T56 is not an option strictly due to cost (it's also heavy and huge). Is the Aisin AX15 4WD trans as good as I've read? Would a Toyota (3.0/3.4), Nissan (3.0/3.3), or Ford 3.0 trans be good options?

 

[d24tdi]

The Toyota W56 and R150/151 trans are pretty well known for being durable behind a TDI, seems like a solid choice. My R150F in my 1993 pickup never had an issue behind my lightly warmed up AHU, although I was not approaching the power/tq figures you are considering.

Have you considered a T5? They are fairly easily found, cheap to buy and rebuild, and come in enough flavors that you might be able to optimize for your configuration. For example Ford Mustang spec has the shifter location further forward vs GM F-body spec. tdconversions offers adapters for both SBF and SBC. Be careful though as the T5 also came in different flavors of strength IIRC. For example one from a 4-cylinder Mustang is not the same as one from a V8. V8 style lives behind a 300 lb-ft 5.0L from the factory though so plenty of torque capacity. There is also the World Class series although that's probably overkill for a TDI.

Seems like folks have found the AR5 Aisin trans from the recent GM small pickups to be a solid choice with wide availability as well although not sure what hoops you would be required to jump through on adapting one behind a TDI.

 

[Bavario]

The Toyota W56 and R150/151 trans are pretty well known for being durable behind a TDI, seems like a solid choice. My R150F in my 1993 pickup never had an issue behind my lightly warmed up AHU, although I was not approaching the power/tq figures you are considering.

Have you considered a T5? They are fairly easily found, cheap to buy and rebuild, and come in enough flavors that you might be able to optimize for your configuration. For example Ford Mustang spec has the shifter location further forward vs GM F-body spec. tdconversions offers adapters for both SBF and SBC. Be careful though as the T5 also came in different flavors of strength IIRC. For example one from a 4-cylinder Mustang is not the same as one from a V8. V8 style lives behind a 300 lb-ft 5.0L from the factory though so plenty of torque capacity. There is also the World Class series although that's probably overkill for a TDI.

Seems like folks have found the AR5 Aisin trans from the recent GM small pickups to be a solid choice with wide availability as well although not sure what hoops you would be required to jump through on adapting one behind a TDI.

Thanks, d24- I have looked at the T5 variants and would definitely get the WC (World Class) for it's strength and shifter options. Post 1990 (Tremec) T5's have the more desirable strength to handle the torque I hope to have. I've read a lot about spline numbers being a factor, so if someone can chime in re the importance of this, I'm all ears.

 

[buzzboy]

For my swap I needed a longer distance from bellhousing to shifter. The Z32 trans worked out best. They shift smooth and are pretty strong.

 

[Bavario]

For my swap I needed a longer distance from bellhousing to shifter. The Z32 trans worked out best. They shift smooth and are pretty strong.

Good to know, buzzboy. Did you buy used, rebuilt, or new? Looks like the shifter has some adjustability, too. I see there are kits to mate them to LS engines, so I have to assume they can take some torque.

 

[buzzboy]

I got a takeout from Car-part.com

Multiple shift options. The same transmission is in trucks and 300ZXs so you have a few different factory shift points as well as Xcessive Manufacturing makes a few shifter kits.

 

[jimbote]

Audi awd 01A or 01E. The rear output turns reverse of the engine, however, you can use the audi rear diff or a diff from a tacoma, tundra, sequoia etc in the rear for correct drive wheel rotation. I have not done this swap but itching to see it real world. The front diff and flanges can be completely removed and flange holes plugged or welded shut. The center diff/torsen must be welded up to function properly. These transmissions are plentiful, cheap, and strong. Already proven as a rwd only drift box and no adapter plate needed.

 

[PickleRick]

R154 is another stout one that fits the 3.0/3.4 Yota both pattern.

More than a few drifting Supras out there abusing them.

 

[zeke5551]

Audi awd 01A or 01E. The rear output turns reverse of the engine, however, you can use the audi rear diff or a diff from a tacoma, tundra, sequoia etc in the rear for correct drive wheel rotation. I have not done this swap but itching to see it real world. The front diff and flanges can be completely removed and flange holes plugged or welded shut. The center diff/torsen must be welded up to function properly. These transmissions are plentiful, cheap, and strong. Already proven as a rwd only drift box and no adapter plate needed.

This is off the wall, but you mentioned that an Audi 01A output turns opposite engine rotation. And then said that it can be corrected by using a tundra or tacoma rear end. I'm in the proccess of putting a 1UZFE Lexus V8 with it's auto trans in my wife's Willys Wagon with a early Mustang "9 rear end. Beings the Tundra V8 is a derivitive of the 1UZFE does the tundra rear end turn opposite? Most guys adapt manual behind the Lexus V8. I actually built a TR6 with a IUZFE and a T5, but would like a an auto for my wife. Thanks, for the help

 

[jimbote]

This is off the wall, but you mentioned that an Audi 01A output turns opposite engine rotation. And then said that it can be corrected by using a tundra or tacoma rear end. I'm in the proccess of putting a 1UZFE Lexus V8 with it's auto trans in my wife's Willys Wagon with a early Mustang "9 rear end. Beings the Tundra V8 is a derivitive of the 1UZFE does the tundra rear end turn opposite? Most guys adapt manual behind the Lexus V8. I actually built a TR6 with a IUZFE and a T5, but would like a an auto for my wife. Thanks, for the help

No, the toy REAR pinion turns clockwise to move forward. I was saying use a tundra or tacoma FRONT diff in the rear but flipped upside down. You could also just use an audi rear diff.

 

[zeke5551]

Very good, I was concerned there for a bit, thanks so much