727 lost 2nd gear

[msbaugh]

Check out the pictures, I guess they speak for themselves!! ...The low/reverse drum/band looks to be in bad shape but I don't know a ton about these transmissions.  The servo piston as seen in the pictures looks to be completely jammed in the housing where the return spring? is located.  How catastrophic is this and I'm guessing the trans needs to be pulled....

I'm thinking about pulling it out and throwing down some coin for a 4 speed, then I'll rebuild this one and sell for coin to go towards the conversion!  It was two years ago I adjusted the bands in this thing, maybe they were too tight or loose  but look at the debris in the bottom of that pan! 

[roadman5312]

Thats just ugly. Yep, gotta come out. 

[msbaugh]

Turns out all the ugliness in the bottom of the pan was from the rear band.  Obviously since the rear servo/piston was stuck, leaving the rear band applied at all times.  Explains why reverse and manual low worked just fine.... when I manually shifted to 2nd it would go limp... this is because the rear band would not dis-engage.  I'm sure the band needs replacing as well as the drum which probably is grooved from the damage. 

I'll take the time to R&R the whole tranny.   I'm going to put billet servos in as well as new red lined bands and a new drum.  Will take a look at all the planetary/bolt in sprag/valve body/and other upgrades while I'm at it.  Going to pull it apart and do the rebuild myself with the help of some videos and books.  Should be fun!

[734406pk]

Turns out all the ugliness in the bottom of the pan was from the rear band.  Obviously since the rear servo/piston was stuck, leaving the rear band applied at all times.  Explains why reverse and manual low worked just fine.... when I manually shifted to 2nd it would go limp... this is because the rear band would not dis-engage.  I'm sure the band needs replacing as well as the drum which probably is grooved from the damage. 

I'll take the time to R&R the whole tranny.   I'm going to put billet servos in as well as new red lined bands and a new drum.  Will take a look at all the planetary/bolt in sprag/valve body/and other upgrades while I'm at it.  Going to pull it apart and do the rebuild myself with the help of some videos and books.  Should be fun!

The Torqflite 727 is a nice and easy transmission to build. 2 things that I've found very helpful are an ATSG repair manual for this transmission and Dr. Tranny's Assemblee Goo. The manual is step by step, plain English and detailed. The Assemblee Goo makes clutch pistons etc easy to install (usually with out seal tools) is low melt temp and nice and sticky for those thrust washers. Summit has it p/n 19250 $7.97 Good luck with your trans project! Remember to clean the cooler and lines and air test the trans before valve body installation (can save a ton of grief later).

[msbaugh]

The Torqflite 727 is a nice and easy transmission to build. 2 things that I've found very helpful are an ATSG repair manual for this transmission and Dr. Tranny's Assemblee Goo. The manual is step by step, plain English and detailed. The Assemblee Goo makes clutch pistons etc easy to install (usually with out seal tools) is low melt temp and nice and sticky for those thrust washers. Summit has it p/n 19250 $7.97 Good luck with your trans project! Remember to clean the cooler and lines and air test the trans before valve body installation (can save a ton of grief later).

Thanks for the advice... and words of encouragement! I've got a new, monster big, stacked plate trans cooler from b&m mounted and ready to go on the car already! The inlets and outlets are covered, of course. I've also got Teflon s.s. Lined hose rated for trans fluid to route to the coolers, as well as a magnetic external inline filter.  I'm still thinking about bending hard tubing, but don't see a huge gain from how long it takes me.

The only thing that worries me so far is pressing in any new bushings and matching my torque converter!

I just ordered the new pro-street turbo-action cheetah full manual, forward pattern, rear band apply, no throttle linkage, valve body. I think it'll make me very happy.

[734406pk]

Wow that's radical tranny build! Worthy of a Pro Steet car! I'm sure you will be happy. Converter matching is hit or miss. You can do all your research but you never know for sure if it's right until you try it. The basic rule of thumb is to have your stall speed close to where the camshaft is starting to come in. There are special tools used to press in the bushings. You can have a mandrel made up and use threaded rod to pull them in as needed. You want to avoid using a hammer in any way  to install bushings as it will mushroom them.

[msbaugh]

Just finished disassembly of the 727. I've got some problems... Exactly as I thought it was too.  Take a look at my pictures.  The low/reverse band and drum were locked together and as a result of a stuck lever/servo the band would not release. The band and drum are both beyond repair.

I have a big problem though. My rear servo is cocked bad in its bore to the point that it's under tension but not even contacting the retaining piece. Look at the picture. Any tips on how I can safely remove this???

I am hoping the servo bore is not damaged.... That would put a serious hole in my pocket if I needed a whole new case... What do yall think?

[RCCDrew]

Hmmm. Do they make a sleeve for that bore?  They make them for many servo bores.

[msbaugh]

Got everything removed! Wasn't as bad as I thought. I'm just going to polish the bore with a bit of emery paper and I'll be good, no gouges. Anyone have a recommendation for a new drum?

I'm building this to be good to 650 hp for a future build. Don't see a need to buy a billet drum. I will however get solid, red lined bands and billet servos so this doesn't happen again

[crash340]

From what I have read, do go billet steel drums, bolt in sprag and so on, DO NOT use billet Aloy drums unless its a full up race car, yes they are fine for the street but they must be checked frequently.

[msbaugh]

One more question. After removing the sprag and inner race there's a small groove on the inside of the case. Is this normal?? In Monroes book I see the same groove in his pictures. Want to confirm with someone else that this is ok.

[crash340]

Im not 100% sure but others will chime in, that is normal, there is a thrust washer/bearing kit to use once that mark gets to a point of being to big.

[edl94]

Be sure to upgrade to a bolt in sprag. The press in will not take big power. Yes that looks normal.


Update: Sorry I see in an earlier post you were going to do the bolt in.

[msbaugh]

Im not 100% sure but others will chime in, that is normal, there is a thrust washer/bearing kit to use once that mark gets to a point of being to big.

Do you know at what point it is considered "too big"?

I'm doing some research and found the bearing "case saver" you mentioned.  I can catch the lip with my fingernail VERY easily.  Any idea what would happen if I just put it back together as it was and ignored the lip? Lol!

I really don't want to machine the case or search for a new one

[crash340]

I'll try and find the info in a manual I have,