My son's 83 244 Turbo has an ailing auto tranny. Are there any problems replacing the worn AW71 with a AW70? I have located two very fresh 70s in my local pick and pull ... but I'm not sure if they are suitable for use behind the T charged engine. Also I'm wondering if there are any compatability problems when it comes to swapping a 70 for a 71. Any advice would be greatlly appreciated. Thanks.

To All ....

A good bit of advice ... thank you all very much. I think I will try to find a later model AW71 ... and swap the tail cone to accomodate the mechanical speedo. I'd rather have the AW71 tranny behind that engine if possible ... the 70 might work but with my son driving who knows for how long. This helpful information is just another example of how the Brick Board is an invaluable resource for Brick owners. I would encourge you all to send a few bucks Jarrod's way to assure it continues. Thanks again.

The AW70 is designed for the naturally aspirated engines, while the AW71 was designed to handle the more powerful ones. I've always been under the impression that the 03-71 and 03-72 transmissions had different parts to accomodate higher power from the engines to which they were attached. I could be wrong, however.

There is a bona fide problem with finding an AW71 that will fit your son's car because it needs to be an AW71 with the speedo pickup.

That limits you to an 85 or older 240 Turbo. I don't know if the early 760 Turbos had a mechanical speedo pickup, so those might work as well. If nothing else you'd have to switch the bellhousing on the 700's trans. Either way, the supply is not nearly as good as finding a later 700 series AW71L, which are literally a dime a dozen.

Honestly, unless your son is really light on the gas and never pushes the car, the AW70 isn't the world's best bet.

The bellhousings work for all B21/B23/B230 series engines ... the tailcones are the ones that would differ.

Even AW-series trannies without the speedo gear can accomodate one. Just swap the tailcones and gear from the old to the new. Make sure that the rear flange bolt is tight ... if not, your end result would be a bouncy speedo, as the big gear that drives the speedo gear is just held in by the rear flange clamping the spacer.

Don't forget to change the rear engine main seal while the tranny's out. Check the front pump seal on the tranny too before putting it in ... you don't want yank it out again to do it one week later.

If you have to go with the 70, there isn't any fitment issues - both are the same dimensions, same mounts.

-- Kane

Interesting. That just answered a longtime question of mine--whether or not the speedo gear would actually be able to work in the newer transmissions.

There are such a ton of later AW71s around, it would be a shame not to use them on the older cars too.

Maybe I'll get a couple (the ones I have right now are all right) and start experimenting...

Besides as replacements, ones with lockup converters really help out in gas milage. It's almost like a 5th speed. Downfall is acceleration ... it's gonna lack up there due to the low gearing.

They're straight swaps on cars originally with the AW70's and 71's. Older ones equipped with the 3-speed AW55 and BW55 need some work - new holes will have to be drilled into the frame members, and through bolted, as the tranny is longer for the OD portion.

Such a swap was done on my old '79. Besides having got 31mpg highway, it wasn't even revving 4k at about 110mph. :) Hates hills, though ... tall gearing and a finite torque out of a stock B21.

Alas, 2 weeks after the swap, I was involved in a t-bone accident, where the other driver was going about 50mph. But testament to its strength, I was still able to walk out. The other party didn't fare quite as well, and were carted away.

-- Kane ... her 5-year old was in the front passenger seat, with no booster, and the airbag deploying.

This is from personal experience.When I had my 84 242Ti converted from a stick shift to a auto the only tranny I came a cross was a AW70.Needed the car so I went for it.It only lasted about a year.Did not complement the motor's power and did not handle the heat too well.e.g. I drove it across country from LA to NY.By the time I got there it refused to shift from first into second.Had to flush the tranny throw in some Lucas tranny additive and made it back home.Later on I installed a AW 71 from a 760Ti.

One can feel the difference between the two trannies.My advice is to wait for a good AW71.Good luck.

I dont think there is a difference other than the torque converter specs. Turbo has a higher stall speed. Other than that.......

The AW71 is the design specifically for the turbo engines, of course. How long the AW 70 might last and even if it would be any more short-lived, I do not know of any info.