Re: IML: torqueflite nonsense

[dardal@xxxxxxxxxxxxxxx]

Mike and all, here is my experience with seventies torqueflites.  My 68 LeBaron
came with a lockup converter torquflite from 78.  This transmission failed
because the converter got permanently locked (Mike, you remember, we discuseed
this a couple of years back and you had provided some usefull input).  I
suspect the valve body was the culprit.  However, the mechanic had insisted to
rebuild the whole thing, which he did, but that's another story.  When he took
it apart, he showed me the planetaries, and he told me that if this
transmission was original, it would have had more planets and biefier gears. 
Now, the guy is not a Chrysler guy, so he may have been wrong (all that is
inconclussive).  The friction material in this tranny was 80% gone, but the
main reason for this premature wear was that the installation of the kick down
mechanism was not done right, so the tranny was shifting with insufficient
pressure (again, that's another story).

So now, we put back the transmission together with new clutches and bands and a
brand new low stall converter, and I get to drive the car (I selected low stall
to reduce the wear on the lockup clutch, which I knew was the weak link of these
transmissions).  What I noticed is that the shift from 2nd to 3rd at WOT was
real hard on the transmission.  You could observe the tach.  When you manually
shifted the transmission from 2nd at 4500 rpm (~90 true mph) to 3rd, the rpm
was supposed to drop to about 3100 rpm or so (based on the 1.45:1 ratio). 
Instead, the transmission could not slow down the engine, the tach kept on
showing 3500 rpm until the car accelerated on 3rd gear to a speed high enough
for 3500 on 3rd, about 105 mph.  This was all transmission slippage.  (400-500
rpm for a few seconds) until the vehicle speed cauhgt up with the engine speed.
 In contrast, my other 68 with about the same power (if not a bit more) and the
original 68 transmission that has about 100K (real hard) miles since its last
rebuilt, shifts right away from 4500 rpm in second to about 3100 on 3rd.  After
we installed a shift kit to raise the pressure, the shift got better (as far as
I know, the other one does not have a shift kit).  The way we interpreted this
miss-behavior of the transmission is that the clutches and bands and/or the
pistons were not big enough to handle the earlier 440.  But may be we missed
something.  I don't know what we missed, but it appeared that the 69 440 was
too much for the 78 gear box (this car has a 440 from a 69 NYer, and a bigger
cam).  Yes, there is was a transmission cooler.

As a side note, that mechanic was always a chevy guy, but got to appreciate the
power of the 440 a lot more than he used to.  He almost admitted that the stock
440 was as strong as his "built up" Chevy 427.  He was impressed how the 440
propelled that huge of a car.  A car heavy enough that his forklift could not
pull and move around when the converter was locked(he is using that forlkift as
a tow vehicle for dissabled cars).

D^2   

Quoting mike sutton <mikanlin62@xxxxxxxxxx>:

> The changes in the 727 over the years were few,  not to go into the detail 
> to list them all but there was a change in the number of splines on the 
> input shaft  around 65,  the front clutch bushing was made a bit wider 
> around 71 or 72, the valve body had changes along the way to reflect the 
> difference in cable shift linkage versus non cable,  the part throttle 
> downshift was added at some point , in the mid 70s the angle of the 
> planetary gears was changed slightly, there were others and Im sure someone 
> will call attention to something I missed or some other bit of trivia.
> 
> Unless you are flat out going for high horsepower applications, and I mean 
> double or more than the factory was delivering, youre not going to see any 
> serious differences in what a 78 or a 74 or a 67 or whatever year of 
> aluminum case 727 can handle.  They were more than robust enough to handle 
> the torque and horsepower that was being sent to them, and even the much 
> maligned lock up versions had problems with the TORQUE CONVERTER more than 
> the transmission itself.
> 
> Dont take my word for it though since I can only speak from experience in 
> repairing and rebuilding the silly things over the years,  as well as seeing
> 
> first hand the kinds of race use that basically stock transmissions are 
> capable of taking with only the most basic mods done to them.
> 
> Mikey
> 62 Crown Coupe 
> 
> 
> 
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