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Discussion Starter · #1 ·
The epic tranny rebuild from he!! is finally over.

There was drama every step of the way. I was able to find a donor without the bell housing anomalies, got it for nothing, but it was actually a TH375. Didn't matter, since I would be using the innards out of my busted COAN anyway. Atleast that was my intentions at the beginning.

I found some additional damage that got me thinking. Besides having 11 of the intermediate lugs blown out of the case, the snapring landing (for the intermediate piston) in the center support was wiped out and both the intermediate and direct drum pistons had damaged outer seals. It's understandable that the Intermediates seal could be cut, half of it had nothing to retain it in it's bore, which could also be what caused the clutch pack to shear the case lug landings. BUT, I supect that the piston seals in the direct drum may have been damaged during installation, which would explain the somewhat lazy 2-3 shifts, as well as, having to replace fried direct frictions once under warranty and twice later myself. In hindsight, I should have pulled the piston when I replaced them. The constant friction debris, despite running a remote spin on filter, obviously had it's effect on things. The governor, modulator and pressure regulator valves were all stuck. During the last year I repeatedly pulled the gov to free it up.

The finished product uses the donor case, center support and pump (with the COAN pressure regulator spring/shims). The reverse feed plug was transfered along with the COAN valvebody, spacer plate and check ball location. The rest of the hard parts; 300M Alloy Input, Steel Drums, 36 element Super Sprag, etc... came from the COAN. Main line pressure seem to be in order (Can't find the original COAN dyno sheet). I didn't record them and was literally hanging upside down out of the drivers door just to see the guage. Everything but low and reverse were a bit over 160, low 180 and reverse nearly 240. I should still be about a quart low on fluid, only put in 10 so far.

Although brief, I did take it out for spin. Shifts are solid, 3rd is considerably better than ever before. I have found one issue, it doesn't want to automatically shift into 1st when coming to a stop in drive. Exactly what it used to do when the governor would stick. The governor is out of the donor, as it had much better valve movement. I only had three stop and go situations, so I may be premature in my accessment. Have to find out for sure tomorrow.

Otherwise, it appears to be a success (knock on wood).
 

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Sounds good so far.

Sure appears to be sticking governor. Often, when you are starting off and it's in 2nd a few manual downshifts to first will free it. Or a few manual up and down shifts from 1-2 to 2-1. It takes very little to stick one. Did you install the screens/filters in the governor feed lines?


JIM
 

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Discussion Starter · #3 ·
Like I said, I only had three stop and go situations. Will take a little longer ride today. I did install the screen. Oddly enough, it came in the COAN seal kit, but wasn't present in the original tranny. Probably why the governor was always sticking on me.
 

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I knocked most of the snap ring lugs off the inside on my case too when I broke it.
 

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Discussion Starter · #5 ·
I knocked most of the snap ring lugs off the inside on my case too when I broke it.
That seems to be popular lately. In the month, or so, that it took me to get my car back on the road, several TCer's posted on my various threads with similar failures. I meant to go to the Rossler website (recommended in a post) to look at an intermediate brace that they offer, but never got around to it. One of those, "outta sight, outta mind" things. I think that I'll do it right now, if for no other reason than to see what it actually looks like.
 

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Glad to hear your back on the road hope you get the gov. figured out. Good luck!!
 

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Discussion Starter · #7 ·
Took a look at it, simple enough concept. The problem, as I see it, it may be only applicable in a manual VB tranny. Not entirely sure, but, with it mounted on the intermediate band lug, the band likely has to be eliminated. At present, I'm not ready to lose the engine braking function.
 

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There is a thrust side to those snap rings as with any snap ring, did they install the snap ring correctly? I have seen many transmissions go up due to the snap ring not installed correctly
 

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Discussion Starter · #10 ·
As far as blowing the lugs out. I don't know which snap ring landing failed first, one probably contributed to the other.

I have another disturbing issue, one that I have assembled as is. The snout of my converter has some bizarre perimeter (not in the lug slots) galling where it sits inside the pump gear. Presently, I have one alternative, the 10" Art Carr that came with the TH400 that I was originally going to use as a donor. It was briefly behind the 540 a couple of years ago and seemed to function fine. I have no real information on what performance level that it was built for.

Anybody have an idea as to what would cause this kind of wear.
 

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Aftermarket bushing looks like caused that, when you do the pump bushing you should have the converter to check it and clearance as needed by polishing the converter or in our case taking it up the highway to ATI
 

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Discussion Starter · #12 ·
It's a different pump and bushing now, but I'm sure that the converter will do a number on the new drive gear in the pump in short order. It has to come from a wobble of some sort, since the two pieces turn together. I have always had a VERY slight engine vibration right at exactly 1900 rpm. Recently, it seemed to be a little more noticeable. Might be time to run it with the converter backed off in an effort to isolate the cause. To be honest, I don't know if it still evident. Guess I'll find out shortly, have to pick up my boy from school within the hour.
 

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As far as blowing the lugs out. I don't know which snap ring landing failed first, one probably contributed to the other.

I have another disturbing issue, one that I have assembled as is. The snout of my converter has some bizarre perimeter (not in the lug slots) galling where it sits inside the pump gear. Presently, I have one alternative, the 10" Art Carr that came with the TH400 that I was originally going to use as a donor. It was briefly behind the 540 a couple of years ago and seemed to function fine. I have no real information on what performance level that it was built for.

Anybody have an idea as to what would cause this kind of wear.

THAT WEAR IS CAUSED BY THE INNER PUMP GEAR "CHATTERING" ON THE CONVERTOR HUB. THIS IS WHY I ALWAYS INSTALL NEW PUMP GEARS WHEN I REBUILD ONE!!!!!! THIS WEAR IS MOST COMMON ON THE GEAR SURFACE ITSELF. I HAVE NOTICED THAT VEHICLES THAT DO A LOT OF IDLING IN GEAR TEND TO HAVE MORE OF THIS WEAR. IF THE TRANS CONVERTOR IS LEFT LIKE THIS, THE PUMP GEAR WILL WOBBLE AND DESTROY THE "CRESENT IN THE PUMP". IT WILL THEN DESTROY THE PUMP. THE WHOLE TIME IT IS DOING THIS, IT IS CIRCULATING FINE METAL PARTICLES THROUGH THE TRANS!!!! THE BUSHING ACTUALLY SETS FURTHER BACK ON THE CONVERTOR SNOUT.
 

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Get your self a G-force 6 speed like I did and quit fooling with those slush-boxes. Then you can actually run down the highway with the common folk without zinging that 540 and getting 5mpg :D
 

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Discussion Starter · #16 ·
This is an old thread, but appropriately titled, as I just stuck the tranny back in yesterday ....again. Hope this doesn't become habitual, the latest was from sprag failure, less than a month after blowing the int lugs out of the case.

I had Art on the phone about COAN reconditioning my converter. Pulling this thread back up on page one was the fastest and easiest way to show him the snout damage. Not altogether sure of what such an operation should cost. The $250 estimate seems a bit steep to me, but not nearly as much as $900 for replacing it.
 

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Just having a little fun with ya' Rowdy. $250 is the going rate. That's what ATI gets to refresh a converter. Seriously, I hope your tranny problems are behind you :)
 
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