T-407/TF 727 TransGo Shift Reprogramming Kit Install

[Michael Mayben]

In this thread:

http://www.forums.IHPartsAmerica.com/transmission-tech/2246-torqueflight-1-2-2-3-shift-points.html

One of our ihon customers, Jesse b. Has ordered up a "built" tf 727. Part of that package included a request for the installation of a transgo tf-2 shift reprogramming kit.

In Jesse' thread you will see an entire 727 valve body disassembled down to the last part. That is necessary in order to verify that the core valve body is surgically clean and has no issues whatsover.

If I'm installing a tf-2 kit into a functional valve body that is not contaminated, it's not necessary to tear it down that far for installing the system.

This valve body core is a "full throttle kickdown" version which is by far the most common unit used in all ihc apps through the eop of of the '76 stuff. Though it's entirely possible that someone has modded an earlier valve body using a "partial throttle kickdown" module. Some '77 and later sii use the partial throttle kickdown system, I have no preference for one over the other.

In the last several months, transgo has completely revamped this kit as compared to what they have supplied since 1975 or so. This kit is not designed for "ease of installation" and I'd highly recommend that it be installed only by a slushbox tranny pro that is experienced with the 727 box. The instructions have been majorly re-worked (but not for the better!), you must have a complete service reference also in order to tear into the valve body, the instructions will definitely leave ya hanging!!!

Some of the mods that were done with the earlier versions of this kit are no longer performed, instead...other changes have been incorporated in order to make this kit applicable to all versions of the 904/727 three speed unit (with or without a lockup converter which ihc never incorporated in any truck tranny). Ihc also never used the 904 version of a torqueflite.

Idea here is to give you an overview of what is involved in the installation of a tf-2 kit. There a few additional parts that must be installed in the transmission itself,...in order to do that you must have the tooling needed to r&r the low/reverse servo and be very familiar with the process of doing so to prevent damaging any seal rings or rubber lip seals.

There is much more attention to detail involved in upgrading the valve body than is covered in this short how-to...the instructions do not go into that detail so I'm not going to either! This is not a step-by-step/in exact order kinda deal...each kit install will be somewhat different depending upon how far the assembly was torn down. But if anyone is interested in attempting to do one of these upgrades on their own, I'm willing to work with ya as always!

This first pic shows the separator plate marked for attention. There are many versions of this plate over the years!!! And you must make a positive id regarding which plate you are working with in order to perform the correct mods.

The steps here involve drilling out various holes using the appropriate drill bit size that is supplied in the kit.

 

[Michael Mayben]

Here the upper valve body casting (it's zinc so ya really have to be careful here!) has a supplied drilling fixture installed. Then a "stop" is installed on the supplied drill bit and the stickout is set to the specified depth. This can be done with a hand drill motor or inna drill press.

 

[Michael Mayben]

This is the cutaway portion of the upper valve body casting that has been partially removed during the previous operation.

 

[Michael Mayben]

"some" (not all!) upper castings require a hole to be drilled into the bypass chamber.

No...that is not a "flexible" drill bit...but the pic looks like it! I do this step in a drill press equipped witha cross-slide vise for accuracy.

After the hole is drilled, the inside must be carefully de-burred.

 

[Michael Mayben]

This is a component of the throttle pressure valve assembly. The stem end gets shortened by approximately 1/4". That is grinding operation done carefully by hand on a belt grinder with plenty of water to keep it cool.

 

[Michael Mayben]

Here you see a portion of the upper valve body casting that has had a "groove" cut in at a specified location. Transgo advises using the edge of a file for cutting that slot, I use a carbide cutter inna flexible shaft handpiece.

This is a mod that is absolutely necessary that goes hand-in-hand with the replacement manual valve supplied in the kit.

 

[Michael Mayben]

Regarding this valve body upgrade, Jesse has requested the the "shift command" feature be activated. This mod allows the transmission to be manually downshifted into any gear...at any speed!!!!! In other words...at 60mph you can stick into manual 1st and expect some dire consequences!

There is an advantage or two to this feature in an offroad sitch if the driver is aware of the feature. And I do use this feature on my own rig when pulling the trailer onna backcountry/super-hilly logging road with a rock surface. It's saved my ass more than once onna downhill!

So the 1>2 governor valve gets a major grind job. It's best to cut this valve down inna lathe, but it can be done by hand grinding and is very time-consuming. I grind these down by chucking inna drill motor and spinning, while using a grinding stone in a dremel. The actual dimensions for cutting this valve down are not super-critical.

 

[Michael Mayben]

Here we have a comparison of the oem manual valve on the left, with the transgo kit manual valve on the right.

The kit valve is substituted for the oem valve. The differences in the lands are easily seen.

Once the manual valve is installed, the rooster comb is placed back into position temporarily so that the location of the replacement manual valve can be verified and "adjusted" by bending the actuator lever if needed.

 

[Michael Mayben]

Here the location of the valve lands are verified in the modded upper valve body per the instructions.

 

[Michael Mayben]

Now we're gonna actually start the re-assembly of the valve body.

You must pay close attention to the instructions which pertain to the exact valve body being upgraded. There are several variations/combinations of check balls to be installed here, including eliminating one or two if specified.

After all the cutting/grinding/fitting of the sub-components has been completed, all parts are cleaned meticulously once again just before re-assembly. There can be no debris or contamination on any part or down inside any channel. The moving parts are an extremely close tolerance fit in their respective bores and even microscopic particulate will prevent this unit from functioning properly.

 

[Michael Mayben]

I've installed a new throttle pressure lever seal in the rooster comb. Now is the time to do that. The replacement seal does not come in the tf-2 kit, so ya need to obtain a new seal and have on hand before tearing into the valve body.

 

[Michael Mayben]

Here I've re-assembled the upper half, separator plate, and lower half of the valve body, being careful to not allow any check ball to move out of position.

Because I've installed the "shift command" feature, I'm gonna eliminate four of the valve body retention screws and replace 'em with the screws provided in the kit, along with installing the shift command plate.

If you do not enable the shift command feature, then that plate is not installed.

 

[Michael Mayben]

This is a shot of the oem pressure regulator valve along with all new schnizz which controls the "action" of the valve. These are the "new" parts that were not used in previous versions of the tf-2 kit.

The oem prv simply uses a single spring here and has a precise adjustment spec called out which there is never any need to change.

 

[Michael Mayben]

The prv retainer has been juggled into position here and the mounting screws tightened.

Once that's done, the pressure regulator adjustment screw is set according to a spec provide in the instructions. That setting will vary depending upon the end use of the transmission/vehicle that this kit is installed in.

This one has been set for jesses' described vehicle use, the only reason to ever change it is for drag strip use only in a full blown launch with a full race transmission...not hardly a Scout II's forte'.

 

[Michael Mayben]

The valve body is now completely assembled, the transgo brass, high volume filter is installed along with it's companion gasket.

This filter is cleanable/reuseable over and over as long as you are careful in service and don't punch a hole in it.

I wash these out in the solvent tank, then they go through the dishwasher and are dried!

 

[Michael Mayben]

And here's the top side of the completed valve body.

All that's left at this point is to install the companion components in the transmission itself, re-install the valve body, and load it with fresh juice.