727 in my street toy seized up Friday. No clue doom was coming. Small blower on 440,3,600lbs touqey tire killer.
has Turbo Action RVB.
3rd has failed twice with 4 disc,hence the 5-disc this time. Has about 50 passes on it.
Changed rear gear from 3.33 to 3.73 Dana and on its 1st ride felt like the brakes were dragging in a cycle.
Headed home.
Was reluctant to back up the driveway,got the the shop put it in neutral and could push it easy???? WTH...
10 minutes later go to push it into the shop can`t budge it. Back it into shop pull wheels and then axles expecting rear has issue.
Pull driveshaft......... trans. is locked.
Pull it and strip it.
Front clutch pack burnt 5-Koleno/plate
Rear is OK
Output shaft support siezed to shaft,drum chewed up as well were it rides on support.

What fails the support? Lack of lube of course,but why?
Ate 5 disc in 50 passes?
What needs addressed for this issue?

I'm not sure why it ate the clutches but filling the cooler with trash will block the lube to the rear support. Have you been flushing or replacing the cooler after trashing the clutches prior? You should also have the converter cleaned out as the same trash will remain in there. Possibly a cumulative effect.

Hmmm,I guess that is possible. But there wasn`t "trash" in the pan just the fine dust from the clutches,no chunks....
Failure was slipping into 3rd.

I will examine that tho..thanks

There doesn't have to be chunks to block up a cooler. Slipping in to 3rd is another issue that could possibly be determined during teardown. Which I would strongly suggest.

Something is restricting the fluid returning from the cooler, clogged line, pinched line, clogged cooler. Also check the small hole just behind the brass fitting where the line enters the trans, I've seen that hole become clogged. You burnt the clutches as the trans was attempting to overcome the bearing seizing up. Are you using the factory trans cooler or are you running an aftermarket cooler?

Aftermarket cooler in front of the radiator.

When 3rd was slipping in the 1st 2 transmissions,fluid never burnt.

So what does it take to get a good hold of 3rd.??

Cope laughed when I said I had a Turbo Action and 3rd gear issues,didn`t elaborate tho.........

Low line pressure can cause slipping, also, if you've burnt clutches it would be a good idea to take the valve body apart. I've seen silt (clutch material) get into the passages in the valve body that would cause your problem. It will look like mud in there severely restricting flow. This is especially possible if you're using one of those screen type filters.

I am sorry to hear of your trouble with 1st gear.I went through 3 trans like that in 1 year 2 with a Chetah rmvb and 1 with CRT so now I am N/A for now.I busted the 3 planet A&A and froze the trans having to cut off the shell to get to a snap ring to seperate the shafts.I changed from a stacked shell trans cooer to a 10"x14" tube/fine.

Ok thanks for the replies.
Yes I am not as educated on trans. as engine stuff.
Ran 727 in my bracket car for 30+ years never an issue.
This car has an appetite for 3rd gear. I blamed in on tall gear,strong torq. and street abuse. I beat it like it owes me money.................
I shift at 4,800rpm at the track,trap at 5,000 11.0`s et. All bottom-mid power.

So the T/A RMVB`s have been the std when I started in the 80`s.
A 4 clutch high should handle that power just fine....right???

What about the driveshaft bottoming out? I have 3/4" free play. But what if its bending the front segment...just a theory.
It only goes low 11`s but from a roll with traction on the street,it is an animal . Bit of a pig at the track with 100% hook. If I took you for a ride up the valley,then you rode with me down the track you would ask whats wrong the the car BIG difference in performance.
Which is why I went with more gear..

Will check cooler flow and orfice stuff today.

Oh I forgot to say, I love your car.

Thanks

Did/made everything myself except seat covers.

Rear support galling can be the result of poor lubrication, but I've seen them gall with plenty of lube. It's a marginal design.

Best way to go is a roller support but you can't use one with an auto VB.

Is the roller support OK for street use?

I see there is a modified support available with a bushing in it?

Took the VB apart,,,,yeah ...it was dirty.
Now to get it all back together

What filter were you using.

Stock style.
Not the brass screen

Lets see what the clutch fibers look like. Hold the reaction support up to the light. Are the ring grooves square? Or are they worn tapered. Are the rings worn on the sides? How about where the reaction shaft support rings ride in the drum, worn? 4 clutch drum should function fine with a Turbo Action rmvb. Have you checked the pressure regvalve and spring? I'd be testing the resource when its backtogetherT/A arent real high 120ish.
Doug

Your valve body has damage in the same area I have circled. Is this a modification or is this wall damaged?

Flush the cooler and convertor as well after seeing inside that valve body. One other often overlooked possibility is one of the rubber hoses going to or from the cooler may have separated INSIDE, blocking fluid flow. I would replace both/all of the rubber hoses with new hose.

No,not damage. Thats the way they are made. PDF. file on T/A website clearly shows it this way. I went back and looked after you pointed it out.
Either way I will be comparing their picture to my actual part.....