• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

727 Fatal oem design flaw disappointment

70rcode said:
Although misleadingly distracted bolster by external factory oem driveshaft & Dana axle over-build rating & appearance but No dealer garage, instruction book or dash sticker warnings cautions, i made hundreds of youthful seeming safe "slap-stick" 1st gear burnout launches & down shift gear drops totally unadvised & unaware of the Hidden, weakly installed, cheap flimsy tin metal sprague & powdered potmetal massive exploding drum personal injury & total vehicle destruction potential...Now, if I reasonably value my only 2 healthy feet, legs, sack & other vitals + unreplacable #'s match treasure, I've Got to $pend more big bucks on a needless 2nd rebuild just 'cause Chrysler knowingly installed a weak designed & implimented POS between their hi-perf forged Steel crank & expensive (for me) $uper track pack Dana60 option package ! ..... really ticked off........tom.
Click to expand...
That's not been my experience. I have had good luck with the 727's. I've never had one fail in daily driving, and when I went serious racing I bought a 727 from B&M.
 
The sticker shock of adding an unexpected $1,500+ to a transmission build would have most of us posting something?
 
Cranky said:
Oh man, used to do neutral drops then while rolling forward hit reverse and do a 'Jay' turn and hit drive and never let up off the throttle! Had a 79 D150 SWB that got a 360 Super Coupe engine dropped into and I was just royally brutal to that truck. Never did a J turn with it but did just about everything else with it plus dragged raced it and pulled my race to the track once I got one. My 4 speed cars were actually treated much better.....except for full throttle power shifts :D
Click to expand...
I used to do the same thing in my 69 SuperBee, Back up and yank it down into low, and stomp on that 440-6 pack! Smoke would just roll off those Polyglass GT's
 
Jerry Hall said:
We used transmission blankets in the day, and didn't give a crap. Junk yard transmissions 30-50 bucks then. Engines 100-125 and we are racing the next day. It's a wonder that we find matching numbers machines today. If you are going to play, pull your matching numbers stuff and go with a play engine and transmission. I have a 400 based 451 stroker, and Hughes built transmission in my 68 Dart GTS. The matching 383 engine is tucked safely away. I never had the matching transmission so that is that. View attachment 1004160
Click to expand...
Yep They were required at the drag strip I raced at. And a driveshaft loop.
 
oldkimmer said:
But think nothing of adding the 1500 bucks to the motor. My tranny cost $3000.00 just in parts. Then 1100 for the converter. Kim
Click to expand...

I totally agree, it just is not brought up as much in the discussions.
My custom built 9" Ultimate converter was in the range you mentioned, but it does what I want it to do also. Sounds like your trans cost about the same as mine.
The cost of aftermarket parts in the transmission can add up really fast. It can get to the point where the only stock part is the case, and the case even gets modified.

When I did my transmission, one problem I found was that I was buying parts from several different places and the shipping costs were adding up also.
 
Jerry Hall said:
With the HP out the door of the factory, the 727 had enough strength and durability. IMO, it's just common sense if you add HP up front, that you add strength all the way down the line. A 425 HP Hemi up front, a Hemi torqueflite in the middle and a 8 3/4 in the rear, you can beat it all day long and into the night with no problems. Add 200 HP up front, you damn well need to think about the rest. Transmission, rearend, suspension, and tires never need overlooked.
Click to expand...
Did that myself. My one 727 auto. '74 Duster. 451. I redid engine. Ditched the 452 heads (That performed well for their times.) for Brodex B1/BS heads. New rods/pistons. New custom grind Comp cam (Mechanical flat lifters) Compression went from 10.5:1 pump gas to 12.4:1 E-85 fuel. By estimates went from 500+ horse to 600+ horse. 727 has bolt in sprag with Kevlar bands. Rear 8 3/4" Mosier 40 spline axles with spool. And what did I forget? DRIVESHAFT! The car was snorting mad and ready to put down a possible sub 10 sec run. Let the two step button go at amber? And the driveshaft exploded so fast the car didn't move. (Thus exploded before line clocks let go.)

Moral of the story? Im still the weak link!

Camera1 034.JPG DusterClip.JPG Recycler.JPG
 
There was design flaws in 727 from day one .
My friend had a tranny shop back in the day and loved ice storms, the reason was if you got the tires spinning and let off the gas quick the rear tires would override the trans and parts inside would break. And this wasn't just muscle cars , It could be grandpa driving a small block.
Made a lotta money laying under mopars yanking trannys for him to rebuild after ice or snow storms , Odd there were no GM or Fords in the shop during such conditions.
So yes I believe there was a design flaw or under built components and yes I also think Chrysler knew about it.
They would just piss in your ear and tell you its raining out.
Your tranny is worn out , just pay at next window thank you
 
Hmm - a lesson from experience from those in the know. Never heard of nasty 727 flaws like this in all my years having heard the rock durability of these tranny's over Ford and GM. Go figure!
 
I’ll stick with my torqueflites, pulled many gm and fords that didn’t hold together like a flite. Say what you want if they were so bad why did mopar sue others for copying them and win in court. If it’s stock all way thru it’s bullet proof, if you modify something it’s all you then. Just like mopar overdrives are called junk all the time , I laugh, I ran a wrecker for years and I’ve hauled them all! Import and domestic, It’s a machine that’s designed to do one thing and stay in the perimeter it made to work in.
 
I bought my steel front drum, and sun shell from TCS.
Got the 4.2:1 band lever, modified front pump, manual reverse valve body, A&A Ultimate sprag, Billet 4 pinion planetary gear set with torrington bearing, and deep oil pan from Cope (CRT)
Got dual ring seal servos, rear aluminum forward drum, Front band strut and anchor from PACT
I think I got the Alto read eagle clutches, koline steels, bands, rear drum spring, and seal/gasket kit from bulkparts. Not sure they are still in business?
 
Cranky said:
In 56 they were called Powerflites and had a cast iron case?? I remember dad bought a 56 Plymouth Belvedere Sports Coupe and had the 'Powerflite' emblem on the lower right side of the deck lid and iirc it was how it was speeeled.
Click to expand...

Powerflite was a 2 speed transmission introduced late in the 1953 model year on DeSoto and Chrysler. Dodge offered Powerflite when the 1954 model year started, and Plymouth lead up the rear being the last American car to offer an automatic transmission in mid-1954. Last year for the Powerflite in a Mopar car was 1961.

Torqueflite (A488) arrived late in 1956 model year for DeSoto, Chrysler and Imperial. Plymouth and Dodge offered Torqueflite with the 1957 models. And, yes, TF had a cast iron case in 1956, as did all automatics back then. Torqueflite was a V8 only transmission.

First Chrysler automatic to have an aluminum case was the A904 for 1960. It also had a Park position, something that Powerflite never had. The A904 was used on models with the slant six engine and later on the LA block 273 and 318 engines.

For 1962 the 1956 A488 was replaced by the A727 which had an aluminum case and a park sprag on the version used on 1962 Imperials, 1962 Chryslers, and 1962 Dodge 880.

Torque converter lock-up arrived for 1978. Had it on my new 1978 Dodge Monaco with 318. After driving the car for a week, took it back to the dealer so they could increase the speed at which the lock up occurred. Raised it from just below 50 KmH to 70. Transmission was smoother and less busy in operation.
 
70rocde, 727's are plenty tough. I learned how to rebuild 727's with my '70 Barracuda. I used the Slap Stick upshift & downshift all the time. Little did I know that repeated manual downshifts into 1st were hell on the rear band & drum. Melted the rear drum in half. OOOPS. The sprag didn't fail. When I started drag racing, I was told & read that you don't do burnouts in 1st since that could cause the sprag to fail and spin the front drum to excessive RPM's causing it to explode. So I did my burnouts in 2nd or 3rd with my manual valve body 727's. If you aren't doing a burnout in 1st, just standing on it on dry pavement in 1st, never heard of anyone exploding the drum. A neutral drop can do that though.
As cojohnso1 said, the driver is the weak link.
 
A friend was messing around in Farmington a few years ago and took the planetary out of his 727. He still had reverse so he backed it a couple blocks back to the fair grounds. A friend had a trailer to carry it home. I think he had his 383 in yet. It didn't have a lot of poser for 2nd and 3rd gear tire spin on dry pavement. Another reason they have water at the strip for burnouts!
 
toolmanmike said:
A friend was messing around in Farmington a few years ago and took the planetary out of his 727. He still had reverse so he backed it a couple blocks back to the fair grounds. A friend had a trailer to carry it home. I think he had his 383 in yet. It didn't have a lot of poser for 2nd and 3rd gear tire spin on dry pavement. Another reason they have water at the strip for burnouts!
Click to expand...

Did he have an explanation for the planetary failure?
 
You must log in or register to reply here.
Auto Transport Service
Back
Top