Scout II 727 Output Shaft Conversion

[Michael Mayben]

Now we're gonna make another mod that is part of the B&M-supplied upgrade kit. This is a high ratio band apply lever.

This item transmits the action of the servo piston to a "clamping" action of the band around the front clutch drum when the hydraulic signal is applied.

The oem lever has an apply ratio of 2.8. That is a very common lever, though some versions of chrysler apps used various other apply ratios.

The B&M replacement lever has a ratio of 5.0! So that increase in lever apply force, combined with the enhanced friction characteristics of the premium band material, give us a significantly load capacity. And all that stuff is engineered to work with the B&M reprogramming of the valve body.

So first we're gonna remove and discard the oem lever.

 

[Michael Mayben]

Looking inside the bellhousing, we see a internal wrenching pipe plug. Using a 1/4" drive socket extension, we remove that plug, clean it, and then prep it for reinstall by wrapping with teflon tape.

 

[Michael Mayben]

Using a magnet, the pivot shaft is extracted just far enough to allow removal of the apply lever.

 

[Michael Mayben]

Here's the two levers side-by-side.

You can clearly see the "2.8" (looks like a 2.9 don't it?) ratio stamped on the oem part. The B&M lever also has "5.0" stamped on it for identification.

 

[Michael Mayben]

Part of the overhaul process involves removing the accumulator and servo pistons and renewing sealing elements on all. That has been done along with an additional piston modification using a B&M component. That is easier to do with the servo levers (kickdown and low/reverse) removed from the case.

Once the levers are back in position, then the kickdown band goes in and the adjuster and actuator strut engaged. Here ya see the band installed and wrapped around the drum, the notch on the band anchor on each end point forward. It is possible to get the band in backward, but it will bind the drum when the oil pump is installed.

 

[Michael Mayben]

Now we stick the pump in the hole. It's already been prepped, a fresh gasket installed in the case, and the perimeter "o" ring has also been renewed and greased with transemble.

Two homebrew alignment studs have been installed in the case to guide the pump into position. Once it enters the seal area, it's impossible to move it laterally, so the line-up studs are imperative.

A few light taps with a soft-face hammer drive the pump home, it should never be drawn in using the retaining bolts!

All the pump bolts were replaced since the previous builder had butchered 'em, new rubber-coated sealing washers for each bolt are included in a soft parts kit.

 

[Michael Mayben]

After the pump is tightened down, then we adjust the bands.

I'm not going to call out the band adjustment spec for this B&M parts build, the values they specify are only for use with the parts included in this kit!!! Do not use the oem band tension specs or any other spec from any other parts supplier!!!!

Now we're ready to test the servo actions and do a final test of the clutch pack since the pump body is in place. To do that, we use the soft-tip blow gun again with a regulated pressure of 25psi. I've marked the four pressure ports on the case that we're going to probe with the air.

The two in the front rail are for the front and rear clutches. So we apply air to each port in turn and listen for the clutch "thunk" again.

Then we go to the marked ports on the side of the case, those are the apply ports for the servos. When pressure is applied, either the front or the rear servo will actuate.

If....both clutches operate correctly, and both servos operate correctly, then if the valve body is correctly assembled and the bands are right, this unit will shift as it should!

When doing diagnostics on a suspected failed transmission and it's still installed in the vehicle, you can remove the valve body and perform these same four tests from underneath. That does not tell ya whether or not the frictions are any good, but it does tell ya if the bands and clutches will apply.

 

[Michael Mayben]

We're gettin' close now...next up is to clean/inspect and prep the governor assembly for installation.

This has to be done in a sterile manner! We can't have anything floating around in the oil that will cause any governor component to stick. And the governor assembly gets douched with a spray lubricant just before it's slid into position on the output shaft.

Here ya see the two sealing rings have been replaced and doped. In the case of this governor, the previous builder had re-used one of the old rings (it was totally worn out!!) and had used the wrong ring in the other position, it was too large!

 

[Michael Mayben]

Here's the governor assembly after it's installed on the output shaft and the seal rings engaged inside the rear drum support. The parking gear is bolted to the governor, when "park" is engaged on the control lever, a spring-loaded pawl mounted in the tailhousing drops into one of the slots on the gear and prevents shaft rotation.

Notice the snap ring just behind the governor assembly. That item is critical to overall endplay of the output shaft assembly. If this output shaft was for a Scout II, then it would have only the single snap ring.

But...this conversion is for the Jeep output shaft and it does not use a bull gear to drive the transfer case. Since the original d300 (and soon-to-be klune) uses a splined coupling that kinda "floats" in there, a second double thickness snap ring is used on the output shaft to act as a thrust surface against the new bearing in the tailhousing. Good thing I found that buried in the parts stash, I don't know where I'd find one locally!

 

[Michael Mayben]

So now, we see what this has all been about.

The tailhousing has been temporarily installed with a gasket and two bolts to check the endplay of the output shaft. We can't have any bind at this point, that would be a major issue!

This one checks out just fine! So the snap ring is the proper dimension. The rest of the bolts were installed and torqued in place.

The gaskets I use are "universal" versions, once the unit is complete, I'll trim the excess material.

 

[Michael Mayben]

And here's the bizznizz end of the deal where the klune's gonna live.

Hopefully the seal that goes on this side of the bearing will be here tomorrow afternoon and it'll get knocked into position.

Then the inside of this housing will be sprayed with an anti-corrosion inhibitor before the klune is mated. This space does not need to be vented since it's dry.

All that's left at this point is completing the B&M-modded valve body, installing same, and then mounting the pan. Once that's done it will get a final exterior pressure washing to prep for paint or whatever jen wants to do with it going forward. So we'll have one more update tomorrow.

 

[Major Screwup]

Nice mayben, I love the attention to detail, thats what makes the all difference!!

 

[Michael Mayben]

Here's the completed build.

I screwed up in trying to locate the correct seal for the output shaft-to-klune input coupler, working from an incorrect dimension on my part. So terry has located the correct seal and he can handle that detail.

The exterior of the case will be sterilized tomorrow and then loaded out for delivery.

The other half of this story is found in this thread:

http://www.forums.IHPartsAmerica.com/I-h-s-t-o/5432-girl-Scout-2-0-a.html

 

[Major Screwup]

Thank you dr mayben! Did the bogus vent gizmo get fixed right?

I see part of it in the last pic

 

[Michael Mayben]

I didn't change the vent setup afterall. I had some concern about trying to salvage the hole that had been drilled out when that brass compression fitting was installed and didn't wanna risk either wasting the pump housing or end up with a leak at that point once I had sealed the hole.

So that copper tube vent will work ok, it's just ugly!

The Jeep/d300 adapter needs no vent like the Scout II setup had (which had in turn been plugged with a sheetmetal screw!). And I see the klune vent and the d20 vent setup you have fabbed so all three vents can be run into a catch can.

I've got some crc sp-400 corrosion inhibitor we'll coat the inside of the tailhouse and the nose of the klune with before mating the parts. And a tube of sealant to use on the surfaces before bolting together for the final time.

If you have the dimensions for the fasteners needed for the klune attachment, let me know. I have tons of grade 8 hardware here so I can pull out what's needed.

See yawl tomorrow!

 

[Major Screwup]

The klune came with all the appropriate hardware.
Hopefully I'll have a seal, today sometime.

See ya tomorrow

 

[Major Screwup]

The finished product, ready to install

 

[Major Screwup]

It's been a long arduous journey,with at least one major setback, but the project is complete. Preliminary testing in the driveway points to a major improvement. Crawl speed in low/low 1st gear at 2500 rpm is less than normal walking speed, at idle it's ridiculous, about, well really slow.
The gearing is so low that the brakes are over powered, and thats with 4 discs and hydroboost. Looks like there will be some learning how to drive again...

Trail testing to follow, stay tuned...

 

[ladotz]

we're doing a conversion onna sii 727 in order to be able to stick a klune v unit in front of a married d20 transfer case for ihon member terry d.

This involves replacing the oem output shaft in the sii trans with an output shaft spec'd for an early/mid 80's fullsize Jeep with a 727 in front of a d300 case.

In order to do this, the entire transmission must be gutted, as the output shaft/planetary assembly is the last component set to come out of a 727 during service, and the first assembly to go back into the case (after the overrunning clutch has been freshened).

And of course, ya gotta have the correct donor parts for doing this.

About a year ago, I ran up a comparison of the various output shafts we encounter when playing with ihc stuff. This shot shows the four shafts we most commonly encounter, though there are others that were used in tf727 applications used in other oem applications. In this thread, we addressed the differences in the shafts and their respective mating planetary carrier splines:

t-407/tf727 variations and parts differences - IH Parts America

In this thread, we'll concentrate on the other end of the output shaft, the "Jeep end", as we build this trans for the klune.

The subject transmission was rebuilt a few years back by a commercial shop. Then maybe a year ago, it was used as a demo for our club folks (IHSTO) regarding periodic maintenance (fluid/filter change and band adjustment), along with having both of the shifter shaft seals replaced with the trans installed in the girlscout. So we anticipated that this tranny would not require any freshening since it's performed well. Wrong!

Turns out this unit was cobbled when built. None of the rump retention bolts matched, all had heads stripped off by an impact wrench and two of the bolts were partially backed out. No attention was paid to the fastener torque at all, old soft parts were re-used, the rear drum and drum support had seized at some point and then obviously re-used when the trans was put back together. The valve body is a homebrew mish-mash of crap parts. And the low/reverse band has only been partially engaging based upon a really strange wear pattern seen on the friction material and the drum (which is not usable). The worst part,...the bull gear retaining nut had been severely fooked onto it's thread on the end of the output shaft. It took me more than two hours of progressively longer cheaters and the gas axe to finally persuade the nut off.

So along with the output shaft swap, the tranny gets a full build using the B&M -supplied parts. We're leaving nothing to chance here.

The purpose of this thread is to address prepping the sii trans for the klune install, we're not gonna go through a step-by-step tranny build.

Terry brought up a suggestion for doing this in another thread, so I'll move his post to this thread.

Hi michael, I realize this post was a while back but wondering if you know the part number for the Jeep output shaft in your photo comparison of 727 output shafts? I'm looking to bolt a tf 727 to my Jeep d300 tc but the current output shaft I have in my 727 is too long. I need one that extends from the main housing by ~ 7" and has 23 spline. Looks like the one in your pic would do the trick