Yes as long as you have the shim installed before doing so.

Yes, sir. The shim should be here by Friday. I know to be very careful about over spreading the shim when installing.

Are there any oddities in this part of the build that I should watch out for?

Lube it, stab it, follow the service manual. From this point forward after the intermediate shaft is installed, it goes together lime a regular 727.

Just be careful when you install the valve body that the OD/LU plug that enters the case does not get cocked and broken.
Make sure to check the OD accumulator spring in the valve body, they like to break from time to time.

Yes, sir. Thank you for that advice. I know that the plastic housing on the pin is delicate.

I had to halt work on the trans in preparation for a busy memorial day weekend, but work resumes on it tomorrow.

First order of operation is to disassemble the planetary gear train, lube all bearings, and check thrust washer condition. Pre-dissassembly clearance is on the tighter end. I bought the gear train as an assembled unit, but I don't trust that everything is well lubed.

The video series that I have been consulting assembled the planetary gear train component by component inside the main barrel. Do you recommend this approach, or assembling the gear train beforehand and stabbing it?

Any recommendations for increasing the life of this rebuild is appreciated. I have time to order components if there are any parts that I should update.

You can assemble the geartrain either way. The transmission plant built the geartrain, checked the clearance then installed the assembled intermediate assembly.

Be clean, follow the directions in the pubs, run the unit to get the oil level qualified, then run it through the gears with the rear end off the ground through all the gears.

I got the servos repopulated, the intermediate shaft support installed, and seated the overdrive yesterday. It was kind of a bear to seat. I was gentle with it because of the governor tubes, but I had to wiggle and fight it on a bit. Is this normal?

It seated so oddly the first time that I pulled it back off, and boy did it not want to come back off. The second time it seated the same way, so I guess it's just how this one wants to go together. I lubed the intermediate support where it contacts the bushings in the OD, so I know it wasn't because of lack of lubrication.

I used the Sonnax intermediate support, and NOT the oversized one.

Alright, I've got another weird one.

With the reverse drum in place, and a new thrust washer installed, there isn't enough clearance for the snap ring to install into the intermediate shaft support. What did I mess up?

I'm pulling the overdrive back off and making sure that the intermediate shaft support is all the way in. Its torqued to the right specs already but it's not much. I really only need another .020 of an inch to get this snap ring to clear.

EDIT: Pulling the overdrive housing and retapping the shaft support gained me no clearance. Maybe somewhere in the build I mixed up a couple of snap rings and this one is just too thick. I'm off to find a thinner washer or snap ring. Or sand this washer down if a thinner replacement isn't available.

Any advice is welcome if you've run into this problem before.

I think the correct L/R drum snap ring is angle cut on the ends. With the drum out the snap ring should fit in the groove. The correct thrust washer should have two anti rotation tabs on it.

There is nothing in the OD unit that would cause this issue. Only thing I can think of Is the ORC cam/rollers/race are not seated. The race should be pressed on the drum. Make sure it’s pressed on all the way. The cam should be pressed in to the case without any clearance between the cam and back of case.

As for the effort to seat the overdrive, that’s not uncommon. If you used the correct tool to assemeble the OD in the press and didn’t manhandle the unit/drop it before assembly on the trans then it’s just one of those units that’s difficult.

You have to keep the planetary and direct hub lined up during the OD build process.

The snap ring I have is angled on the ends, and it fits in the groove without the washer installed. The washer is also .062 of an inch and has two anti rotation tabs. There isn't enough clearance for both of them, and the washer blocks the snap ring entrance, about halfway, when it's installed

I verified that the cam, and the sprag is seated well but I will tap the cam gently tomorrow with a round brass shaft to ensure that it's seated all the way. I don't have any way of fitting it in my little press.

I read that there are different drums that were used in the 727 and A518, and sometimes get mixed up. One used a delrin plastic washer and apparently didn't have as deep of an indent for the washer, from what I understood. When I was tearing down this trans I didn't find any kind of washer in that drum. I kept all the used parts just in case and I didn't see anything like it when I went through them again. I also noticed that my drum doesn't look like any of the A518 drums I'm seeing. It looks like a 46re drum. Does that change anything?

If I sand the non indented side of the washer to make this all fit, am I going to hurt anything?

Thank you for your assessment of the overdrive. I used a homemade tool to press the OD unit, but I used my alignment tool to make sure everything was lined up, and after installing the overdrive housing I found that it had stayed aligned. The third time installing the housing was much easier and it just kind of drew down into place.

I’m not aware of any differences between the very late style 727 and 518 drum, there may be.

Any drum that uses the snap ring and thrust washer must have the machined step in the drum though.

It has the step in, but there isn't enough clearance. The washer is .062 which seems to be stock, the snap ring is .060 even. I also tapped the cam fully seated, there was about .006 under there. Now it won't allow a .0015 feeler gauge.

I suspect the drum, because the cam is fully seated, and the washer and snap ring still don't have clearance. This is a genuine Sonnax shaft support, so I imagine that it's true.

What's your take, sir?

EDIT: I asked a couple of sellers of remanufactured drums to pull a measurement of that step in, the most common measurement I've gotten back is .088. The one that came in this trans measures .020.

New drum is on it's way. I decided to replace the sprag, as well, just in case. I'll post how it continues once the new parts are in.

Received the correct reverse drum. The drum, metal washer and snap ring all dropped right into place, took less than five minutes.

The first picture shows the wrong reverse drum on the left, and the correctly cut drum on the right. The incorrect cut was .020, and the correctly cut drum measured .088. All other measurements appear to be identical. I'm being specific about the measurements in case anyone else runs into this with one of these rebuilds.

The second picture shows the correctly cut drum step.

The third shows how shallow the original drum was cut. Does anyone know which application would use a .020 cut reverse drum?

Where the band rides, same diameter between the two?

Still looking for my plant info - when I find it maybe there is an explanation for the depth differences.

Sorry, I have been offline for a while.

I've been offline, myself. Busy, as I'm sure you are.

The two drums miked the same in all measurements that I could accurately pull, except for that step in. Aside from one being lipless, of course.

The gentleman who runs the transmission shop I bought it from sent me a new snap ring and an old plastic style (Torlone?) washer. I used the new metal washer with the relief cuts (relief cuts placed toward reverse drum).

He also pulled measurements from a half dozen drums for me and sent me the drum with the largest cup. He said that .075 was the most common he found, aside from the .088 he sent me.

It installed with almost no play, but the snap ring sits firmly in the groove and will move rotate around the groove with a fair amount of force applied. I figure this means that it's seated properly, and is not binding at all.

Finally had a chance to look for my plant info.

Info mentions changes from no thrust washer to a thrust washer.

Heat treated in that countersink area gets a snap ring without the thrust washer.
Non heat treated gets the thrust washer.

I don't have any way to check for specific hardness. I didn't notice any kind of washer when I removed the drum originally, so perhaps the original is a hardened drum. It's now just sitting in a box of spare parts if anyone has a specific need for it.

Thank you very much for looking that information up.

The trans is in the final stages of being built. The forward and reverse drum have been assembled, and fall within spec. The pump will be getting cleaned and checked tomorrow.

Should I air check the servos before I install the valve body?

Also, are there any pitfalls to avoid when installing the VB or inserting the parking pawl down into the overdrive section?

The drum with the blued recess has the hardening I mentioned and does not use the thrust washer.
The one without the bluing is not hardened and uses the washer.

If you plan on using air pressure I would lower it to 30 psi before testing. The rear servo is easier to test if you just install the servo piston then bring it up almost out of the bore then close the apply hole off with your finger tip. Then try to push the piston down. If you can’t the seal is good.

If you used metal seal rings on the front servo piston and retainer it’s pretty difficult to screw those up unless you used a hammer. 😀

Teflon seals should be tested with air like the rear servo using the same pressure rate.

The park rod can easily be placed in the wrong spot. I find it easier to install the rod with the trans vertical, while someone tries to turn the output shaft. The plant actually installed the rod only, then the valve body and they had a tool that held the 3/4 snap ring so it’s could be installed once the rod engaged the valve body.

Thank you for clarifying about the drums.

I absolutely DID NOT use a hammer to install anything internal to this transmission. Two seals on the outside, yes.

I have replaced every single teflon seal, metal seal, o ring, lip seal, plastic clutches etc that I've come across. I trust no seals a second time. Also those plastic sprags kinda scare me too.

I figured that the park rod was going to be one of the pains in the butt. Luckily the trans is vertical so I might just have to stab it and check, rinse and repeat, until I get it right.

I started to worry that I was going to wind up with a faulty build, because of all of the oddities that I've encountered. But everything is coming up within spec, the servo bores looked great, all the seals went in well, and I've got a professionally rebuilt and updated VB that I'm installing. So I should probably relax and just get this thing buttoned up.

Didn’t mean to imply you used a hammer, but that’s about what it takes to damage the metal seals.

I took no offense, sir. I was laughing at the thought. Your advice has been invaluable, and I sincerely appreciate all of it.

I know that slipping that servo into the bore was tricky. I used the back of a screwdriver to tap it so that it would sit flushly and I could press it in by hand. I don't imagine that that could have hurt it, though. The guy in the videos used the back of a hammer, oddly enough.

I grew up working on diesel engines. I've seen people do dumb things to delicate parts with hammers so I do my best to avoid that behavior. I watched a guy deform a very expensive fuel rail because it wouldn't slip into place for him.