Topic: Automatic transmissions

Who's running them?

What do you do to make them last?

The world is slowly losing manual transmissions and it is much more common to find an automatic out there. We want to do something unusual and finding a stick is impossible. I guess I want to be reassured that grabbing an auto would be worth the effort.

Re: Automatic transmissions

You would have to be much more specific.

4T60E...do not even try.

AW70...likely more reliable than all the manual transmissions for the same engine except the M41.

Re: Automatic transmissions

Funny a 740/940 Volvo wagon was something we were considering. My buddy wants to do a Volvo and I want to do a wagon.

Re: Automatic transmissions

johnmcracer wrote:

Funny a 740/940 Volvo wagon was something we were considering. My buddy wants to do a Volvo and I want to do a wagon.

M46 is OK (as long as you rebuild the cone clutches in the OD), but I would not run an M47 in Lemons.

AW70/71 can be killed usually only by one thing...water.  The radiator tank mounted transmission cooler has killed more of them than anything.  Except for some internal gearing, the only substantial difference between that trans and what is in a gazillion Tacomas and a lot of Supras...Toyota used a seperate bell housing.

If you really want to hate your Lemons car, run Chrysler cloud car with an automatic.

Re: Automatic transmissions

So if you were to take the radiator and the transmission cooler and separate them into separate units that would eliminate that fluid crossing?

Re: Automatic transmissions

johnmcracer wrote:

So if you were to take the radiator and the transmission cooler and separate them into separate units that would eliminate that fluid crossing?

Yep but honestly, it took most of them 20 years to cross contaminate.  I just suggest a new radiator.  That said, the radiator transcooler is always a bad idea for endurance racing.  On the street they do double duty of warming the fuild to prefered operating temp more quickly then maintaining it at give or take 195 f.  Cooler is better when racing so get a GIANT cooler and put it where the condensor used to be.  They are simple flare fittings and very low pressure.

Oh, whatever you do if you choose to drop the pan to replace the trans filter do NOT try to loosen the giant nut that attaches the dipstick tube to the pan.  If the bolt holding the dipstick tube bracket will come out...great.  If not cut it and zip tie the tube into a stable situation after.  Honestly...just don't change the filter and instead do a redneck trans flush with decent synthetic ATF instead and be done with it.  Volvo even removed the filter replacement from the maintenance schedule I think in the final 1995 year.

Re: Automatic transmissions

FWIW we ran the 700r4 behind out 305 TransAm for about 4 races. We used an aftermarket valve body to tighten up the shifts. We used our ac condenser as the cooler. Never broke. However the thing seemed like it was always in the wrong gear. They were designed for max fuel economy. We swapped in a 5 speed and the car really picked up lap times.

"get up and get your grandma outta here"

Re: Automatic transmissions

First off, thumbs up on the Volvo wagon!!

Now, we had a 700-R4 in our Camaro we did two races on it and then it blew up.  The next one only lasted one race at which point we swapped out to a turbo 350 and never had an issue since.  We have since swapped out to a Corvette with a stick in it.

We ran an oil cooler out of a cube truck it was about the size and thickness of a hotel Bible.  In both cases we added deep sump pans (cheap and easy swap meet finds!) and...we installed a trans temp gauge.   On hot race days if the trans started to get hot we would back off for a lap or two and then be good to go.   Beyond a BIG cooler I think the temp gauge is a must have for a Lemons auto especially if its in a bigger car like a Volvo wagon.


Best of luck boys.

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Chevy Corvette 1984......and still racing!

Re: Automatic transmissions

I ran ford mustang with a 180k mile 4r70w in one race and it was fine. Just kept it out of OD and ran some full synthetic trans fluid. Didnt even run a cooler - ran out of time - but will next time.

Re: Automatic transmissions

Torqueflite A727 with the most aggressive TransGo shift kit and a giant cooler from a junkyard work van. Ive lost track of how many blown-up 440s its been behind, but nary a complaint.

Interceptor Motorsports
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Re: Automatic transmissions

Mercedes 722.3 (the automatic used in most everything they built from the 70s through around 1995) hasn’t given us a bit of trouble over the years. Synth ATF, external cooler, trans temp gauge all are things I’d suggest for any AT

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Re: Automatic transmissions

Ran a th350 for years once we figured out to run a deep sump pan and ran two of the biggest plate style coolers in series.   And the biggest thing... set it up to never downshift.   We ran around in third 100% of the time and three things happened... 1 we actually got faster because we all drove better instead of crutching bad lines with downshifts, 2- got way better mileage. 3 didnt break it.  This was behind an LT1 in a 3400 lb car.

Team Orca- 3700 lbs of fury!

Re: Automatic transmissions

We've run two races with our '09 Pontiac G6 and an auto and had no issues.  Sorta...we installed one of those cheapy trans coolers and had a line blow-off right at the end of the NOLA race.

Personally, I think a well running auto isn't a hinderance at all.  In fact, we found it allowed us to focus more on the racing w/o having to worry about gear selection.