Conpare Chrysler TF 727 Internals With IHC Guts

Compare Chrysler TF 727 Internals With IHC Guts

Currently I have several TF 727 rebuilds going on in the shop. One of 'em involves converting a Dodge 440 motorhome tranny to a Scout II output shaft/transfer case adapter for a D20. And of course, the Dodge tranny will be completely "built" for a competition-only mud drag rig.

Based upon the amount of email I receive on this subject..let's see if we can answer some questions AND use FACT to illustrate some of the differences found in many of the variations of these slushboxes.

First...not all Chrysler "motorhome" 727's have the so-called "low gear set" as standard. While there may in fact be some out there, they do NOT ALL use any planetary ratios any different from the passenger car and truck variations across the board! So...if you are looking for a poorboy approach to the "low gear" solution for a 727 by acquiring a Dodge motorhome version to rob the planetary system from, you may be disappointed once it's gutted out!

However...in the case of the transmission I'm currently converting, it DOES incorporate a somewhat "stronger", four pinion planetary set (only the rear carrier is shown in the pic), as opposed to the three pinion planetary set as used in both fullsize and Scout II versions of the 727. Again, this feature is part of the speculative "I thinks" that are commonly kicked around regarding the "motorhome" trannys.

Second topic...output shafts.

There were MANY variations of the "tailshaft" used on these trannys, depending upon intended application. Some unique ONLY to Chrysler, some to IHC, and some to AMC.

The "front end" of all TF 727 output shafts are basically the same/interchangeable, though there were detail design changes made over the evolutionary life of this unit. It's the rear section of the output shaft which has many variations which precludes a simple "swap" of external componentry.

The shaft on the left is the Dodge motorhome unit, this one incorporates a tailhousing that is UNIQUE to the motorhome application. It also uses a splined yoke retained by a nut, most Chrysler apps of the 727 use a "slip yoke" at that point which rides in a bushing in the tailhousing. Also note it's overall length...and it's NOT the longest one available (for a Chrysler app).

The center shaft is from a fullsize 727 as used in squarebody pickup/Travelall apps.

As may be seen, overall it's IDENTICAL to the Scout II shaft shown on the right, EXCEPT for ONE difference! Note the areas with the dimensional callout. That is where the shaft rides inna BALL BEARING (NOT a bushing).

But see the difference in the shaft O.D. at that point? The bearing for the fullsize shaft is a "standard" item. The bearing for the Scout II which is mounted in the transfer case adapter is a SPECIAL bearing! Notice that the shaft is reduced in O.D. at that point as compared to the fullsize shaft.

All other dimensions of the two IHC shafts are the same.

So you can see, that in order to "convert" a fullsize output shaft to use with a SII/D20 transfer case, the shaft must be machined to the proper bearing mount dimension.

However, that makes it impossible to use the output shaft from a Scout II 4x4 application, in a fullsize tranny since it's alredy to small in O.D. to make that swap.

Purpose here is to show what needs to be considered when doin' boneyard forays for TF 727 stuff with the idea in mind of mixing and matching parts.

I'll add to this thread over the next few days as these various projects evolve. This is the first opportunity I've had myself where I have examples of three DIFFERENT 727 slushboxes tore down!

 

Thanks much Micheal. Your definintions and 'splainin' is highly appreciated.

Keep 'em coming.

GR

 

Thats interesting Michael. So what is the diameter of the Dodge shaft?
A standard bearing in that size (range) is gonna have a bore of 30mm (1.1811) or 35 MM (1.3780).
So some genius decided 33.88MM (1.335) and 31.22MM (1.230)
was a good idea? Can you say specialty OEM parts?
I believe the AMC shaft is the same as the Scout shaft, but wouldn't swear to it.
Do the Dodge boys have trouble finding bearings as well, I wonder?

How's your supply of good, reusable bearings?

Turning the shaft down is a scary proposition. Sounds like a formula for disaster!

 

I'm recording all critical dimensions Terry. I'm getting inquiries from several sources regarding those "special" SII bearings and was gonna call ya this week to see what the status is. I've been pimpin' 'em through Dan's operation since he had some available on the website a few months back. IF Dan doesn't wanna keep messin' with 'em, I 'm sure that Jeff at IH Only North will!

AFAIK, there is NOT an issue with sourcing the Chrysler app bearing, nor the fullsize bearing for the IH tailshaft. ONLY for the Scout II as you well know! The dual seals are available off the shelf anywhere (including YORE shelf??).

By the way, this is Monte's tranny I'm dealing with right now, the muddobber that's up on yore lift!

I now have a COMPLETE set of all IH parts list (MT books) and will be doing a complete analysis of IH p/n's for all versions of the 727 as used in the various applications. The output shaft support bearing is the #1 item to research. The list does not get into critical dimension/sizing so I'll cross that to the bearings I have samples of and then get with you to cross over to off-the-shelf items vs. custom-made. I'll also measure each sample for actual dimension reference.

Dave Wimsett just left here and we talked about this tonite, showed him all the parts/details, he didn't know about the weirdazz SII bearing deal either! I did show him pics of YORE ceramic replacement. Tomorrow he's calling his close buddy at Transmission Exchange/Portland and see if he's gotta market for those bearings, as you know, in the past they did NOT deal in those...OR the dual seals used in the SII transfer case adapter. If TransEx DOES have an interest, then I'll hook ya up, maybe a chance for ya to peddle sum stuff through a market that WILL pay the price??!! Dave LUVS to put folks together to swap dollars!

I agree about machining the shaft for workaround. All the shafts show evidence of "localized" heat treating in the bearing interface area, so machining might not even be possible except by someone such as yourself that has the proper tooling.

This is just ONE MORE REASON to NOT haul IH-pattern TF 727 trannys to the scrap yard!! Bare usuable IH-pattern cases are bringing up to $150 from corewhores, and Scout II output shafts/support bearings are irreplacable.

 

When I took my *extra* output bearing to the local bearing house, the guy there measured it and said (IIRC) that the OD was standard, but the ID bore was not. I guess this is due to the sleeve/spacer that goes through there and against the t-case input gear.

BTW, when I inquired about the bearings from Dan, I was quoted $125.
The guy I talked to at Super Scout Spls said that their rebuilds use used bearings that have been inspected, and he said he hasn't seen many *bad* bearings.

There's also a '76 Traveler at the local PickNPull that has a complete drivetrain, including a 727. Might be worth a trip back there to pull it...

 

Here's a couple of things from bearing 101:

The original bearings were supplied by New Departure, a division of GM, the went defunct in the 80's.
The OD should be the same on all of them, 80 MM (3.1496) The only thing different is the bore (ID)
There are several bearings that can be modified to fit but the CORRECT one is a MAX type. Some guys are using conrad types, while that will work, the originals were MAX for a reason. The difference is the ball count. A conrad will have 8-9 balls and a MAX will have 11-12 balls. The MAX will also have a loading notch, where the balls are pressed in. MAX is a much more expensive bearing, (due to lower production quantities) and after being modified is a bargain at $125.00.
Another thing to look for is the bearing width, A suitable candidate for modification/replacement needs to be the same width.
It is not possible to "inspect" a bearing without disassembling it.
The "inspection" these things are getting is a quick rinse in solvent, some clown spinning it in their hand and calling it good.


Class dismissed.


Michael,
The ceramic bearing you put in my transmission, is NOT the standard replacement item. At $300 + not too many binder bubbas are gonna spring for that. I did that just for fun.
The standard (modified) bearing is an all steel MAX type.
I have one left and have stopped production due to lack of interest.

 

Terry/Dan HAS the "correct" bearing solution for the SII app. Bite the bullet and do it right!

ANY bearing can be machined "custom" with the right tooling...Terry does this onna routine basis! But there is MUCH more to it than just hole size! The bearing would HAVE to meet/exceed "spec" for load/application, some would...MANY would not!

http://www.precisionbearings.net/

I HAVE contacted ONE other supposed "source" for that bearing, but the folks that "claim" to have 'em are smokeblowers and can't deliver, they obviously DO NOT completely understand the sitch. And they wanted $95 for a so-called "new" bearing which they didn't even know the dimensions of...and DO NOT have available as "advertised"! And got NO SOURCE for filling a so-called "order"! BS'rs!

Terry worked out this "special" bearing deal long before I ever met him! That's his business (not especially SII bearings that no one wants to pay for though!) and he has the ability to do this. That kinda work does not play into a no/low budget approach to messin' with this junk. And he has all known resources regarding this subject right there in the shop, so he can QUICKLY figgr out what works, what doesn't, and what the CORRECT workaround might be!

Don't know about the Jeep 727 deal Mark ...yet! But we are actively looking for one for a comparison of parts. Terry may already have that info.

The fullsize bearing is WAY too small in OD for installing inna D20 transfer case adapter. Anyone with machining skills and TIME (and parts) can do ANYTHING regarding this stuff. But I see NO NEED to do all the hokuspokus...just acquire the CORRECT bearing which Terry "might" be persuaded to put back into the gene pool, far less trouble than doin' machine work which "might" not be the best route. And Terry's version cannot be compared in any form with a workedover "stocker"!!! His solution IS rocketscience stuff that will last through the ages!

If the subject bearing was NOT a "special", then we would not be having this discussion, jes' get tha part of the shelf and install.

The "sleeve" deal is not the issue Erik...it's just the way IHC "spec'd" the tranny/transfer case adapter, so the output shaft had to be produced for ONLY that application...no telling WHY this was done, they could have just as well used MANY standard bearing apps and not tried to have the wheel re-invented for such a relatively "small" production run as the SII over the years.

AS for "used" bearings, unless SSS has x-ray vision, I myself would NOT go there. The PRIMARY fault I find with these bearings is NOT failure from lack of lube/overheat/overload. It is CORROSION damage! That is because these rigs go underwater and water seeps in through the vents and lays inside until the tranny fails (and it WILL!). And a "rebuilt" from a commercial source without "disclosure" of "used" parts, that is just totally irresponsible.

Or...the trannys lay out in the weather in boneyards and junkpiles for years and fill with water! I have TWO right now with that issue, even though from the outside, they appear OK.

The correction for water damage when a rig is used in offroad mode??? Re-locate the tranny vent AND the transfer case adapter vent. Then mod the transfer case vent also! Just DON'T let tha water in!

I'm NOT trying to pimp for anyone, but there ARE known solutions for issues such as this. My purpose is to point out and VALIDATE this kinda stuff so that FACTS are available here in these forums...and NOT smoke.

More to come...

 

What is the OD of the fullsize bearing?
I vaguely remember building a bearing for JD's TA a few years back & it did have a smaller OD.
Is the difference 2 X 4 VS 4 x 4 OR Scout VS fullsize? The former I think.

Michael, If you have any old/junk/or questionable bearings, I'll look 'em over for possible rebuild/repair/modification. I'll cut you a special bubba deal, I owe YA!

 

Are the full sized bearings and seal still avalible new? Is it the same as used on the mopar motorhome?

 

Wail Monte's jackin' me 'cause I ain't WORKIN' on hiz stuff insteada JAWWIN' about hiz stuff! And...he's all hot an bothered about the output shaft bearing in HIS conversion. He sed he'd run ta Carlton an score the remaining bearing Terry built NOW if need be!

But I got Monte handled, the adapter housing and bearing I'm using in hiz is GOOD (but "used" and I HAVE disclosed that to him!). Monte's now settled down knowin' his bawls iz guud!

Terry...keep that bearing in the vault..I'm SURE it'll be needed soon! I wuz confused about the "materials" used, I now remember ya did somma both...the glass bearings and the conventional "specials"! But I'd LUV ta bee able ta just put onnea yore glass bearings in my environmentally-sealed, nitrogen pressurized, wall-hangin' display case!

The bearing you fabbed for the JD T'all tranny was still OK when I rebuilt it for Mike Roth last June after the "acquisition". It certainly was NOT YORE bearing that was part of the many issues with that unit!

Here's what I got dimension-wise...Terry can so some figgrin' and tell US what's what, we already know tha story on the SII 4x4 version.

Pic shows all three apps lined up, all three bearing I.D. is the same, but O.D. and width and ball count is not.

NONE of the three have any of the "normal" manufacturer's identification/numbers visible. I've NOT tried to source any of these from my local bearing supplier, but Terry can do the same as far as tellin' us IF the Chrysler and fullsize bearings are standard items or "specials".

The bearing in the pic for the fullsize tranny is rough...I've got one more tailhousing fora IH fullsize to inspect and see if the bearing is OK, if not, I may need ta put inna order!

I don't wanna "speculate" right now about all the IH apps regarding fullsize 2x4, 4x4, and Scout II 2x4. I need to really research the IHC parts lists for tranny variations by p/n, then make some kinda "I think" statement for folks to blow out! That is gonna take time, and I need ta git Monte wound up so Terry can have his lift back! The deadline for that is May 17!

So bearing p/n, companion seal p/n, and workaround bearing/seal combo info will soon be summarized!

If ya think THREE variations here are too many ta deal with, I just found a FOURTH variation on the floor cart, a later Dodge 440 pickup/Ramcharger? tranny which was married to whatever transfer case they used, don't know year model/app. That output shaft uses yet a FOURTH size bearing, but it appears to be a "standard" item (in this case a Nachi bearing) and not a special. That number izza 35BCS2N.

So now...do ya kidz understand when I beat ya up about the "all TF727 trannys are the same!" statement??

 

Well I am glad my little project is being used for some education. I can't wait to see the final product. See you on the 17 th and I'll be bringing a passenger, I mentioned BBQ Chupa and they got all excited.

 

35BCS2N is not a standard number. It's either a OEM number and/or another special bearing.

See what ya started, Monte??

 

If I hadda REAL job and all tha cashola YOU got Jim...I'd come get 'em, and find onena Doc Stewart's rigs and stuff 'em in the azzzend when he ain't lookin'.

Seriously...I don't know! But they are prolly worth more for the future than alotta the stuff you ARE moving!

I know Jeff has about 10 or so cores also, eventually they may find their way up here to be used for builders. We're still gotiatin'! But Jeff ain't got room for any more either!

Put at least one in tha azzend of the rigs ya ARE movin' so's they will stay dry.

I know a few months back, Mike Fiock hauled a tandem load of 'em to Schnitzers, I beat him up severly about that! Momma dun thinkin' I'm startin' a boneyard here in the office already, she sez NO trannys in the office, or axles either! But 727's are like dawgs ta me, I want 'em ALL!

 

OK Terry, additional info on the SII tailshaft bearing.

Our mutual "new best friend", Dave the Gear Man just left here AGAIN!

He tells me we may be looking in the wrong place for these bearings since they are NOT standard industrial items. He's got some "transmission only" bearing application data that may shed some light on this and will do the workouts tomorrow. He took the previously identified bearings with him so he can do the metric measurement deal as you. My metric calipers are gone to the great beyond (i.e., in someone else's tool box). Should have the answers by noon tomorrow he's coming back up here to help me whip some down trees into firewood and get stuff ready for this weekend's IHSTO Coonsmoke.

And two of the bearings in question are actually "sealed" bearings which have had the seals removed (along with any I.D. data which was molded into the seals). The SII bearing is NOT a sealed design (with seals removed).

After Dave left I finished sterilizing the transfer case adapter w/bearing that is going into Monte's build. That's part of that SII tranny you swapped to me for your buildup. Once I got it cleaned up, using an LED light I was able to make out some VERY faint etchings on the inner race, first time I've found any I.D. on these specials.

This one appears as: "MRC 307 M6" and is a 10 ball unit with a loading slot. Does that number mean anything to ya?

He told me the SAME story as you mentioned regarding New Departure, and I did NOT tell him what I knew first! He sez he runs into similar deals all the time in doing manual transmission builds, but he has an extensive network of folks that deal in this stuff nationwide and can always find what he needs. Once the SII bearing is positively I.D.'d, he'll put the word out on the street he's looking for those and see what pops up.

More to come...