Is the torqueflite an inferior design from a thrust-washer pov?

MoPar~Man

MoPar~Man

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I came across a comment posted on the web along the lines of the 727 having a lot of loaded thrust washers, hinting that maybe other transmissions (or modern transmissions) don't have that? One of the outcomes of that being that it's bad for oil (I guess causing oil shear, reducing oil life, making it pointless to use synthetic ATF). Any ideas on that?
 
Perhaps the commenter "on the web" might have desired to see Torrington Bearings instead of mere thrust washers? At least, as a wear item, as a thrust washer wears, protecting the surfaces it wears against, it just allows more shaft movement. Any bearing, as it wears, usually stops turning. What might the best alternative be in any transmission?

I suspect the wear characteristics of full-syn atf would lengthen the service life of any thrust washer. IF the full-syn fluid also increased friction life too, suddenly we've got a 200K+ transmission.

CBODY67
 
Never had worried about that. One night, years ago, a transmission shop owner showed me how much larger in diameter the friction plates were in a 727 than for the allegedly equal THM400. The TF was quite a bit larger in diameter and square inches of material, which means more torque capacity. How many related thrust washers there might be is not worth being concerned with as torque capacity and durability are key transmission metrics.

CBODY67
 
The thrust washers haven't been a problem since the first 727 in 1962. Again the cheysler trust washer are wide and beefy. I've pulled some trans pans off for a fluid change and half a thrust washer is laying in the pan.

Yes newer (mid 1990's and up) transmissions seem to use Torrington bearings more than thrust washers.
 
It's not that the washers aren't big and strong, it's that their mere presence means oil getting sheared by them? And maybe not just 1 or 2 of them? That there's a better way if you want to avoid that?

I guess in the big picture it's not a really big deal, but someone threw it out there.
 
Yep, no big deal. Built tough and will last a long time with normal maintence. We used to service transmisdions every 2 years or 24,000 miles. Fresh fluid and a new filter makes them last. Adjust the bands while you are in there.
 
I just pulled apart a 727 from a 1970 D200 with 110k miles. Burned up direct drive clutches. With the rebuild kit came 2 thrust washers that i mic'd and they were the same as the old ones. After rebuild using the old washers end play was still well within spec's. And these are the factory installed ones from 1970.
 
Sprag durability in first gear is an issue with A727. Avoid burnouts in 1st gear is a way to prevent damage. And if doing a burnout in first gear, avoid going from tire slip to instantaneous full traction. If spinning and then hook under high revs/power, things can explode. That’s what A727 known for. Sprag issues in 3rd gear are something to manage for TH400.
 
Might need to understand that a burnout in "1st gear" means manual 1st ("1") gear, rather than the "D" 1st gear, in the TF.
 
Put the trans in 2nd, let it 1-2 shift, come out of the burnout box in 2nd before you let off.
 
Please read this so you understand when the low band apply is operating.
1734268066587.png
 
BrooklynBeer said:
So you don't shock the sprag and have it explode. John is a great guy. He helps out many folks with his extreme knowledge for free. Watch this
Click to expand...

What he is saying applies mostly to manual valve bodies, where if you start in second gear, you are actually starting out in second.
That does not apply to 99% of the readership here , that have fully automatic valve bodies.
Start in 2nd? You're still in first, but without applying the low gear band.
see the above chart. Hope this helps.
 
I've seen the aftermath of a 727 explosion. A friend broke the rear on the line and even though he knew better, he just took the chance things would be OK. New rear end and never took the trans apart to check the sprag. The bits blew a large hole in the floor, with pieces just missing his leg. This was in the days when all we had was the stock sprag. After that, I started using a trans blanket... and so did he.

With the manual valve body, we always did burnouts starting in second and shifting to third. With a street car, I stayed out of the burnout box as the street tires (at the time) didn't get any real benefit.

This is a kind of famous pic and it often said it was from a neutral drop. That's been debunked as actually a sprag failure.

1734367361151.png
 
BrooklynBeer said:
So you don't shock the sprag and have it explode. John is a great guy. He helps out many folks with his extreme knowledge for free. Watch this
Click to expand...

Great video! I understood what happens in that scenario, but he explains it better than anyone else does.
 
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