First questions on my 727 rebuild journey

[miller]

Not impressed with AARP, but that's just me.
If it helps, this is a stock HP set, that's typical. You can see about how much clearance on the holes.

 

[dvw]

The front servo does not need the hole blocked to activate. Doesn't sound correct, they don't normally leak much. However I have never used the sleeve repair kit. I'm assuming this is it?
http://www.sonnax.com/parts/1826-2nd-gear-super-hold-servo-kit#tabs1-instructions
If so I'd be looking at the outer sleeve seal rings. If that servo leaks it will kill the 2nd gear band in a hurry. The clutches will leak some. I use normal shop air pressure.
Doug

 

[AR67GTX]

The front servo does not need the hole blocked to activate. Doesn't sound correct, they don't normally leak much. However I have never used the sleeve repair kit. I'm assuming this is it?
http://www.sonnax.com/parts/1826-2nd-gear-super-hold-servo-kit#tabs1-instructions
If so I'd be looking at the outer sleeve seal rings. If that servo leaks it will kill the 2nd gear band in a hurry. The clutches will leak some. I use normal shop air pressure.
Doug

Doug - I haven't tested the servos yet. My front one is stock other than polishing the bore, replacing the seal rings and the spring/spacer swap from the TransGo TF-1 kit. I did notice that when I installed it, the lower piston slid right in with little resistance so I'm hoping it holds pressure OK.

I did not use that Sonnax kickdown kit. I used one of their bore saver kits on the intermediate accumulator. Here is the one I used.

http://www.sonnax.com/parts/1850-intermediate-accumulator-sleeve-kit

Would that Sonnax second gear kit be a worthwhile addition in my situation? It would be easy to install right now.

Thanks on the clutch leakage.

Miller - I'm going to look into the flex plate hole issue some more. If I can come up with some way of centering everything I may re-drill mine. Any hole is going to have to have a few thousands oversize. After working with manual transmissions for years it just seems weird to not having something that really centers the transmission input like a crank bushing.

 

[miller]

Question - I got what appears to be a proper 10 inch pattern, stock flexplate from Mancini - but it still has 3/8 inch bolt holes. The stock 5/16 inch bolts are lost in them - but they are definitely smaller than 7/16 inch. So what accurately centers the converter on the flexplate - just the engine dowels? I didn't spend a lot of time looking at the crank when I pulled everything apart - does the crank center the converter snout in the bushing recess that closely? Seems sort of imprecise.

I'll try to explain on the centering of it...or, toss some more mud at it!
Imprecise...not really, considering that yes, the flexplate flexs. That's mostly to absorb vibrations, since if there was none, it could wear out parts a lot faster.
If you notice in the pic of the flexplate, it sits between the crank and the converter (of course!) First thing mounted up is the flexplate to the crank, that has the center hole that fits over the crank end, and pretty much 'centers' it at the crank. The crank/flexplate bolts lock it in place, and much of the time lines up to balance it, via bolt pattern/balance marks.
When the converter itself is installed (with the trans itself), the converter snout fits into the flexplate hole, and the rear of the crank. Of course, just the block/trans housing dowels line up trans to block, and the two centers, unless something is flat wrong. That puts all those parts inside the accepted centers, considering the flexing of the rotating parts. Bottomline is, it works.

 

[miller]

My front one is stock other than polishing the bore, replacing the seal rings and the spring/spacer swap from the TransGo TF-1 kit. I did notice that when I installed it, the lower piston slid right in with little resistance so I'm hoping it holds pressure OK.

Just a suggestion, for any servo piston that uses o-rings, especially more than one o-ring.
I'd pull the piston back out. Take the upper o-ring off, and test fit the piston, with the lower o-ring in place. Pushing the piston into the bore, the o-ring should have a slight drag. If it does not, it's too small. Need to go to the next bigger size, that will fit the groove, and have some drag in the bore. If it doesn't, it will leak.
Any o-ring seal should be checked for fit...one by one...to know it's going to do the job.
O-rings have to seat themselves, to seal right.

And, what size bolts were on the converter/flexplate. Some of that aftermarket stuff can toss kinks into things.

 

[dvw]

I'm missing understood. You meant air checking the clutches. Slide them both onto the pump. Apply air at the case feed holes in the pump. This will check the sealing rings on the shaft/reaction support and the clutch piston seals. These are the only possible leak paths. And as stated earlier you will hear a thud and some leakage on the front (high/reverse) clutch.
Doug

 

[oldbee]

Trying to remember- you can use a "normal" size wrench to adjust low-rev&frt.clutch settings w/o a torque wrench... With a wrench 5" long, go 'pretty' tight and then back off the number of turns specified. I know, sounds weird but the short length of wrench lessens your torque. Have done it more than once on mine.Your bicep/forearm may be more than mine!!

 

[AR67GTX]

Pretty sure I'm having trouble getting all of the friction plates in the rear clutch to engage with the front planetary. See the notch area in this picture.



In contrast you can see it's seated deeper in this photo I took during disassembly.



Plus I have only about .016 end play. I may have to figure out some way to stand the transmission up on end - to get the clutches all seated. Anyone have any other suggestions.

Miller - I understand the flex plate centers on the crank hub. But is there really engagement and self-centering of the converter hub into the crank? Otherwise the converter can end up bolted to the flex plate off-center. I don't see any sort of machined, precision converter hub to crank hum fit there. At least with a manual transmission, even if the bell housing is out a little, the pilot tip on the input and crank bushing bridge over that - and with a stock bushing and the floppy front ball bearing input, any slight misalignment is usually a non issue. Apparently it's a non-issue with a torqueflite too.

 

[AR67GTX]

Just a suggestion, for any servo piston that uses o-rings, especially more than one o-ring.
I'd pull the piston back out. Take the upper o-ring off, and test fit the piston, with the lower o-ring in place. Pushing the piston into the bore, the o-ring should have a slight drag. If it does not, it's too small. Need to go to the next bigger size, that will fit the groove, and have some drag in the bore. If it doesn't, it will leak.
Any o-ring seal should be checked for fit...one by one...to know it's going to do the job.
O-rings have to seat themselves, to seal right.

And, what size bolts were on the converter/flexplate. Some of that aftermarket stuff can toss kinks into things.

I'll check out the front servo sealing further. I haven't checked to see if the valve body has to be in place first to air test it.

Both the torque converter I took off of the car and the new one I bought have 5/16 inch threaded bolt holes. I ended up with a Hughes 2400 stall, 11 converter. It looks pretty much like the converter that was on the car so it may just be a rebuilt Mopar converter.

 

[oldbee]

AR67- nope ur not seated in the last 1-2 clutch discs. Tailshaft down & wiggle, rotate to get them seated. It happened to me also!!

 

[AR67GTX]

I think I'm going to have to strap it to a couple of 6 ft 2x4s to stand it up and hold it without resting on the tailshaft. I should have gone and retrieved my engine stand back from the guy I loaned it to years ago.

 

[miller]

Plus I have only about .016 end play. I may have to figure out some way to stand the transmission up on end - to get the clutches all seated. Anyone have any other suggestions.

Miller - I understand the flex plate centers on the crank hub. But is there really engagement and self-centering of the converter hub into the crank?

Alrighty...like oldbee, probably had a clutch plate, or two dis-engage, so the drum assembly isn't seated. Or, something in the clutch stack isn't right, piston seated? Endplay right? That happens real easy, especially if your trying to put 'em in sideways. One of the main reasons to stand the trans up, and 'drop' the assemblies into place. While I'm at it, if you haven't done it yet...the bands...put them into place, before you stack the clutch drums in.
If something does NOT look right, look again and be sure. Or, you could easily be pulling the trans back out, and down. Though, that gap your looking at can change, if you made a change in the clutch stack, like adding another clutch plate. Just be sure, so you only have to do it once!

To the flexplate. Flexplate to crank, yes, it pretty much self centers, if the right parts are used. Understand your meaning, between mounting up a standard, compared to an auto. Not that much difference. Still have allowable side clearances, to keep things from binding.
But, as I'm sure you know, the flexplate to converter also needs the correct bolt-up, to keep it all in line, and not kill the trans pump bushing. Something else on those bolts, in case you don't know...thickness of the bolt heads. Their thinner than normal, for clearance. The flexplate, as things are spinning, allows the converter to 'float' a little, foreward and backwards in it's limit. Bolt heads are thinner, so they don't get into the rear of the block.

 

[miller]

So you'll wind up with main case, with tailshaft in place. Makes it all much easier like this...make a short stand, drum, or anything only tall enough for the length of the tailshaft. Idea is a piece of plywood, with a hole for the tailshaft to go through, holding the trans nose up, the tailshaft off the floor. The lower the better!

Errr...hint.

 

[miller]

I'll check out the front servo sealing further. I haven't checked to see if the valve body has to be in place first to air test it.

Page 142 in the handbook, shows the ports, to air check clutches and servos. No, the valve body is not installed, yet.

About the bands adjustment. Really needs the right amount of 'torque' applied, that just sets the correct 'grip' the bands give on the drums, when that servo applies. Then, so many turns backed-off, for free turn clearance. Just trying to do it by hand, you could get a slipping/burnt band, or one that won't release right.

 

[AR67GTX]

Thanks - haven't gotten to the servos yet. I figure they can be dealt with anytime before the pan goes on.

Since I'm reusing my plates and friction plates the gap should look the same. I'll work on it some more when I can stand it on end.

I did replace my torque wrench yesterday although after checking about a half dozen places including Sears and major FLAP stores without luck - ended back at Harbor Freight for a cheapy Pittsburg Tools one again. I have the correct thin head flex plate bolts.

 

[dvw]

Just stand it on the tail shaft. Twist and wiggle.

 

[oldbee]

Sometimes cussing a little helps too!!

 

[AR67GTX]

OK - i'm officially bum-fuzzled. First off I am sort of proud of the stand I rigged up for the cost of 2 - 2x4s and some rope.

And my hoist to get the heavy bastard up on the jack.



After that it's not so good. The issue a couple posts above is not that I'm not getting all the friction pads engaged - I completely removed the friction plates and steel plates from the front clutch and it still sits the same. One thing I forgot to do originallywas check the planetary end play so I did it in the case with governor and everything installed by tapping the output shaft forward. I assume this still gives me a valid end play measurement. I could get .056 inch feeler gages under the C-clip so that tells me I have something messed up in the planetary area that is causing the front planetary shell to sit too far back in the case - making it look like the clutch pack isn't seating in it. So I took it all apart and here is what I have in the way of shim plates.

















There's a recess in the rear drum housing that looks like it should have a fiber shim in it (second photo up) - but I don't believe it had one when I took it apart. I don't see one mentioned in Carl's book or the service manual unless I'm overlooking it. Is there anything that goes between the rear drum and the overrun clutch?

Otherwise I don't see any shims I'm missing. I had one fiber shim - I think in the clutch packs that was about .060 so I replaced it with a new one of .063. But I think all the metal shims were around .062 -.063 and I re-sued them.

Any ideas what I'm missing?

Where should I shim to decrease the planetary gear train freeplay?

 

[AR67GTX]

I found on page 9 of the "the book" that different thickness c-clips can be used on the front of the output shaft or a shim can be used on the front of the rear planetary. As you can see in the picture - I already have a shim on the front of the rear planetary.

I must be missing something - these are the original planetary sets except for the sun gear which shouldn't make a difference.

Is measuring the planetary end play with the governor and tailshaft installed still a valid test - measuring between the nose of the front planetary and the c-clip?

 

[AR67GTX]

I found on page 9 of the "the book" that different thickness c-clips can be used on the front of the output shaft or a shim can be used on the front of the rear planetary. As you can see in the picture - I already have a shim on the front of the rear planetary.

I must be missing something - these are the original planetary sets except for the sun gear which shouldn't make a difference.

Is measuring the planetary end play with the governor and tailshaft installed still a valid test - measuring between the nose of the front planetary and the c-clip?

Here is why I'm sure it's in the planetary train - assembled on the bench without the output shaft - everything nestles together fine.