It is true. I have rebuilt an A904, an A727 and an A518 (46RH). They are all almost identical except for the A904, the parts are smaller. I think snap rings, front and rear clutches, overrunning clutch, planetaries, ect are the same. There are obvious differences like output shaft, and the OD addition to the valve body.

 

Interesting. Sooo when 727's are so great, why do A518's tend to be, uh, NOT?

 

I was going to ask this too. If the 46RE is basically a 727 with O/D, why is the 727 considered stout and 46RE's are failing left and right?

From what I've read on here, the overdrive unit is very weak on the 46RE, and tends to overheat and cook the fluid, whch helps take the rest of the trans with it. Is that anywhere near accurate?

 

The OD is the weak link on a 46RE, but you can build a serious 46RE, I had one that was good to 1000hp built by Martin Saine, I sold itfor the John Cope Racing 727.

When I get the 46RE rebuilt in my Ram, it's going to Martin...He's the best out there with a 46RE.

 

O/D unit, and torque converters were the weak points. Most 727's were non-lockup, until relatively recently. When either failed, it would smoke the rest of the trans with the debris is circulated thru the system.

 

I wiped one out that way (abusing it with a built 440) but the nicely upgraded replacement was certainly up to the task. My wife hated the whiplash inducing WOT 1-2 shift... I could never figure out how she failed to anticipate and prepare for it. It's not like there wasn't a whole lot of noise and G-force involved well in advance...

 

We had it in a 72 challenger, with fairly skinny tires. On WOT runs, I didn't worry about blowing up the trans, simply because the engine had enough torque to rip the tires loose at each shift. (yeah, even 2-3 shift.....) From a standing start, you couldn't keep traction, but, if you were already rolling, holy smoke, hang on to your eyeballs, or you would be fetching them from the trunk. The car was absolutely insane on the freeway.

 

It was good and hot Street Masters that enabled me to rip the clutches out of my first 727. Once those tires were hot they stuck like they had spikes. They'd break loose, of course, but they were as close to slicks, traction wise, as it was possible to get. And being spendy mufkers I quickly learned to be choosy about when I hotted 'em up, too.

 

Er uh, hmmm..

Are there options for the 727 in terms of gear ratios and planetary gears that don't exist for A518's?

It's been my longstanding contention that our transmissions short falls in performance is more akin to the silly selection of ratios than anything.. I'd love to see a lower first and second and a wider gap to third.. or, maybe not even a wider gap if the first and second were a little lower.. you know, like a 350 or a 400..

 

Supposedly, the 518 is just a 727 with an overdrive, so one would think, that the different gear ratios for the 518 would also work in the 727...... That's just a wildassed guess though.