Converters are like everything else.  Stock converters are fine for stock applications, but fail in performance use.  And yep, the BD converter I put in my F250 Diesel earlier this year was over a grand. 

John, I do have overdrive in my 69. It just happens to be the 2.50 gears in the 9 inch.

Bullet Bob said he'll sell me his AOD if he upgrades.

Pulling the crank while it’s still on the car, impressive. I’ve read good things about Broader.

Gluten for punishment, I’m with ya. I dropped the crank out of the bottom of a Cutlass Sierra with a sideways 4 cylinder one time, but it doesn’t compare. It was only a half of a motor!!

Greg B wrote:

Excessive hydraulic pressure in the transmission pushing the torque converter forward.   Like a valve body restriction, trans brake. 

BTW -  congrats on the new grandchild!

 

 
Grandchild? What new grandchild?

But your excessive pressure has me thinking Greg. Ya, I know, it's dangerous. A bit of history on my 69: When I tore the car down in the mid 90's, the plan was a stock rebuild. So I had a mechanic friend rebuild the fmx. It sat for many years until I needed a tranny to complete the drive train. I pondered other transmissions, but stuck with the fmx, because it was rebuilt and ready to go. One of my mistakes was to use a used  torque converter of which I had no prior knowledge.

When the 69 was drivable before the teardown in the 90's, it would easily chirp the tires in second gear with a worn out 351. I don't believe I've chirped the tires hitting second gear with the 393. The shifts aren't nearly as hard as before, and there is a bit of a delay going into reverse.

A week or so ago I was dumping some trans fluid from a pan which the converter was sitting, and saw quite a bit  of glitter in the fluid. Thinking the trans had shredded the nonferrous wear items, I decided to tear down the fmx. It was pristine. No wear at all, and no glitter in the trans.

I'm guessing the used unfamiliar converter had trash in when I installed it, and maybe some made its way into the valve body. I've read that clogged valve body lines symptoms include delay in shifting into reverse and soft up shifts. I've also read that high trans pressure results in hard shifts. I've never had hard shifts since the fmx rebuild. Not being able to check the trans pressure without it in the car and running is troublesome. I'm thinking of cleaning fmx, cooler, cooler lines, install the new tc, and keep my fingers crossed.

Last edited by rpm (7/08/2018 5:34 PM)

I don't know much about the FMX, but I can tell you a couple things about automatics in general:

1. High pressure alone doesn't cause harsh shifts.  There's a lot more to a shift than just line pressure in the trans.  Shift harshness is mostly caused by accumulation, or lack thereof.  The accumulators control the way it shifts.  Bad shift kits will either fully or partially stop accumulator piston travel to remove the cushioning effect during a gear change.  This results in a harsh shift at anything other than WOT.  A proper shift kit doesn't do that.  You want accumulation, so your part throttle shifts are smooth.  Higher line pressure and other changes to the valvebody and separator plate can still result in neck snapping WOT shifts, but not at the expense of shift feel at other throttle angles.

2. If the trans was just a stock rebuild and now has a built engine in front of it; its not surprising that its performance is lackluster.  It may just be slipping due to all the added torque, which would explain your less than stellar shifts.  The clutch packages and servos need to be matched to the intended power range of the engine.  Stock parts just won't hold.

3. If the trans fluid was never changed after the rebuild the little bit of glitter you saw is likely just from break in.  Just like an engine there's going to be some initial wear that puts some junk in the oil.  If it wasn't all through the trans that to me signifies that the event that caused it is long over.  Essentially whatever caused it created some junk, but the filter did its job, and kept it from circulating back through the trans.  Eventually clean fluid running through the trans flushed all the junk out of wherever it came from, leaving some trash in the pan, but nowhere else. 

4. The big thing to look at is the pump.  They run really tight clearances, and it doesn't take much trash through the pump to screw that up, and cause a loss of performance. 

5. Another thing to consider is what fluid is in the trans.  Ford used F-Type fluid originally, but the frictions in the rebuild kits no longer require it, and you should run regular Dextron/Mercon III or IV (not V though, that's synthetic).  Running the F-Type fluid will result in harsh shifts in a trans that doesn't need it.  Being that the rebuild was in the '90s I'd bet dollars to doughnuts that it no longer needs F-Type.  The C4 I used to have in my car shifted overly harsh for years until I read up on the change in the parts in the rebuild kits, and changed the fluid to Dextron/Mercon III.  That trans was rebuilt around '94-'95 for point of reference.  Nice of the trans shop to tell me to run the right fluid, oh wait...they didn't. 

Ron68 wrote:

6sally6 wrote:

rpm wrote:

,          I know, put a 5 speed in it.           )

My thoughts zak-lee!! J/K
Just the leak was the only indication you had sump-thin wasn't right?!!
If so............that's scary!
6s6
 

BTW -  congrats on the new grandchild!
 

Congrats to 6Sally6 on the new addition.
 

My brother's neighbor buddy who is an auto trans guru thinks he found the cause of my thrust issues. The pic below shows where the snout of the converter connects to the pump. He says "you can see where the depth of the converter hub wear mark is all the way down to the machined flat in the pump gear. I think this is where the problem is. You need at least 1/16 to 1/8" clearance here."

DOH! I'm thinking this points to operator error

Ya Tom, I've read all of Nailbenders posts on his thrust problems. My crank journal surfaces are all polished, pre and post damage   The one thing I've found as a common denominator in my research is clearance issues causes thrust  damage. A poorly finished crank journal won't cause thrust. It may wear the bearing more quickly, but not cause the low mileage damage seen.

My last photo shows where the rear snout of the tc was bottomed out against the pump gear, when clearance is required in that area. This to me, and others, shows there was not enough clearance in the components from the pump forward to the crank. And when the flexplate flexes, as it should, the thrust causes wear to the weak link, the thrust bearing and crank journal.

When I installed the tranny a few years ago, the only critical step I remember is making sure the converter is fully seated. If not, sudden fatal pump damage occurs.  I have no clear recollection of clearance between the tc and flexplate, which is mandatory. I'm pretty sure I'll check this clearance my next go around   The other areas which need proper clearance are the tc front snout to rear crank hole, and tc to flexplate. Mine was good on those last 2 areas.

When I first started researching my damage, the few answers I found were that it was caused by the torque converter. Only a few online threads gave a definite root cause of their damage. Sportsroof69 on vmf was the one of the few to provide a true answer. His was lack of clearance between the tc front snout and rea crank hole. Mine, as all things point to, not enough clearance between the tc and flexplate before before bolting it up.

I take full responsibility in this damage for not checking and writing down all the clearances that are needed. This is especially true when some components are changed.

As Everett Beasley once said, education is not free.

But only if that wisdom is remembered...Grasshopper.

Last edited by rpm (7/11/2018 7:48 PM)

Only 5.0 I ever saw that wasn't rode hard came out of a Lincoln.  They were a Timex engine though, so I wouldn't worry too much. 

WHAT!!!...you didn't weld the trans cross member "laying-on-your-back-too?"!(with no shirt on...like us good-old-boyz)
You shore make purty beadz!!
6s6

You can do it with a MIG too, just crank the wire speed down and the heat up.  It liquifies the old bead and lays down minimal new filler, but allows you to swirl the puddle around enough to make it look like a stack of dimes.  Heh, I've never used that trick before (we need an eye roll emoji on this thing).