T15 To Dauntless

Discussion in 'Flat Fender Tech' started by oldtime, Apr 10, 2017.

  1. Apr 10, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    IMHO the Borg Warner T15 behind the Dauntless is the optimum 3 speed into a flat fender V-6 jeep.

    The Jeep T15 requires an adapter plate between it and the BOP bellhousing.
    Myself I have both an AA adapter plate and a NOS Trans Dapt that are designed to fill the need.
    Yes both adapters have distinctly different designs.

    A new Advance Adapter is pretty steep in price.
    The Trans-Dapt is long out of production and quite rare.
    I've been asked several times to sell one of mine but I decline for now.

    So I've been considering to modify a stock T14 adapter for T15 applications.
    I do believe the stock adapter could be modified to produce an excellent adapter.
    The changes would need to be well done and precise.

    As you know the stock adapter already fits the BOP bellhousing pattern.
    It also fits the Jeep T15 bolt pattern.

    First one needs to address the thickness problem.
    The adapter needs to be reduced from 2-5/8" thickness down to 1-5/8" thickness.

    Basically the hollow middle area of Jeep T14 adapter needs to be cut out and removed.
    Milling of the 2 separate halves perfectly flat again is ideal but a precision job of grinding should suffice.

    Next the two haves need to be re-aligned and welded back together.
    55% nickle arc welding rod works wonders on this type of casting.
    Of course a chamfer for deep weld penetration is required.

    Secondly the T14 index bore needs to be re-sized to fit the larger T15 bearing retainer.
    This must be precisely bored on center.

    Upon installation the original T15 bearing retainer is re-used.
    The Jeep T15 bearing retainer simply indexes into the modified adapter and it is long enough to enter at correct depth into the Buick bellhousing.

    What do you all think ?

    Remove 1" from the middle: (# 941186)
    [​IMG]

    Remove these shifter bosses while were at it:
    [​IMG]

    The bellhousing face: Note the ingenious step design used to index the adapter into the BOP bell.
    No other T-15 adapter that I've ever seen uses this simple design.
    [​IMG]

    The transmission face: Note the 4.25" bearing retainer bore will need to be increased to 4.686 (same as GM or T15)
    [​IMG]

    After modifications, a standard T-15 bearing retainer is used to reach into the BOP bellhousing

    Bearing retainers:
    Standard T-15 bearing retainer = 4-3/4"" long with 1.310 or 1.405 bearing sleeve
    GM # 3741458 bearing retainer = 3-1/4" long " with 1.37" bearing sleeve
    T15 bearing retainer with sawed off bearing sleeve is required for an AA adapter.
    [​IMG]
     
    Last edited: Apr 11, 2017
    mike starck likes this.
  2. Apr 10, 2017
    Keys5a

    Keys5a Sponsor Sponsor

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    I agree that the T15 is likely one of the best 3 speeds, but a later 4 speed (I like the T176 for instance) might be more worthy of the effort, unless you happen to have all the components lying around. Though a T176 might not be as stout as a T15, it should easily cope with the torque of most 6's, and I find them to shift quite well.
    By reducing the thickness by 1", I assume you would be "sacrificing" two T14 adapter plates to make one? The precision grinding of 1/2" material from two plates is ambitious, but with the right machine can be done. The nickle-rod welding (stick weld?) again would be challenging, especially to control warpage from heat. I'm sure it can be done, but this isn't typical garage fabrication.
    For about the same the effort, maybe less, a block of 6061 could be milled to duplicate the Trans-Dapt piece, especially if you find someone with a cnc mill, since you already have a pattern.
    As an alternative to remaking an adapter plate, could a simple 1" spacer be turned to press into the crank pilot bore to use the 2-5/8" T14 plate? This may also require a longer clutch fork pivot stud too. Many years ago, I bought an sdapter "kit" for a trans swap and it utilized a spacer for the pilot bore and worked fine-I just don't remember the application any more.
    I'm not saying these ideas are the way to go, but offer some alternatives to achieve the same goal.
    -Donny
     
  3. Apr 11, 2017
    Daryl

    Daryl Sponsor Sponsor

    Bonney Lake, WA
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    I built a t-98 adapter using almost the exact same thing you described. I had to get creative on the bearing retainer but it all worked.
     
  4. Apr 11, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    The main goal here is to determine an alternative for the Jeep[s wanting to run T15 behind a Buick V-6.
    As of current AA is the only easy yet costly option.
    Advance Adapters Chevy V8 to Jeep T15 Transmission Adapter Kit - Bellhousing Adapter Kits - Drivetrain & T-Case - Store - Chassis Unlimited

    Yes I have several T-18's that I mostly prefer yet the T-15 does have a few advantages in instances when a four speed is not required.
    It should only take a single T14 adapter if I can cleanly cut 1" out from the midsection.
    A good band saw is the ideal tool for cutting away the middle.
    No I would not be grinding away any appreciable thickness.
    just grinding to achieve a consistent thickness for each half in case the saw cut is crooked.
    Yes 55% nickle stick electrode using AC current which produces an excellent weld on cast iron.
    There's Virtially no chance of warpage on thick cast iron.
    1" stickout of the pilot bushing is a really bad idea in my book for a couple reasons.
    The runout gets too crazy and it makes for a longer than desire bellhousing combination.

    Here you see the Trans- Dapt design.
    Note that a GM 3741458 bearing retainer will be required so that it can index into the BOP bellhousing bore.
    The GM bearing retainer is of correct standard length for the BOP housing.
    The retainer sleeve accepts a common 1.37 diameter release bearing.
    [​IMG]

    Here you see the transmission mating face:
    Note that the maindrive oil seal will be fit directly into adapter plate.
    The adapter plate is machined to accept the front transmission bearing.
    So the T-15 bearing retainer is no longer required.
    However the bearing retainer gasket must be installed between transmission and plate in order to prevent gear oil leakage.
    [​IMG]
    IMHO Trans-Dapt made very nice adapters but they are now days exceptionally rare to locate.
     
    Last edited: Apr 11, 2017
  5. Apr 11, 2017
    Jeepenstein

    Jeepenstein Me like Jeep.. Sponsor

    Bucksnort, TN
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    I saw a different approach to this, the T-15 and T-14 input shafts were friction welded in the middle to the correct length so the adapter was not necessary.. I thgouth the guy was nuts but it never failed and he hammered on it..

     
  6. Apr 11, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Hmmnn simply changing the maindrive shaft does no address the different diameter bearing retainers.

    IMHO the inferior T-15 to GM Advance Adapter design.
    Here's the bellhousing face:
    [​IMG]
    Again the GM # 3741458 bearing retainer must be used in order to index into the bellhousing.
    [​IMG]
    Here's the AA transmission face:
    Note: there is no provision for the mainshaft oil seal.
    Nor can it be indexed direct to the front transmission bearing.
    [​IMG]
    A T-15 bearing retainer must be used to hold the transmission front bearing in place.
    It's also required to accept the oil seal.
    But this full length retainer interferes with the GM retainer.
    [​IMG]
    So the T15 retainer must be sawed off.
    [​IMG]
    With this inferior design the GM retainer is used in front of the T15 retainer.
     
  7. Apr 13, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    So anyway I texted myself into doing as I have already proposed.

    Moderators....This topic might be better if moved to the Fabricators Forum

    Fabrication details to follow
     
  8. Apr 19, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    The Original Jeep T-14 adapter weighs in at 13-1/2 pounds
    First thing I do is remove this excess shifter boss.
    [​IMG]


    Next I scribe 1" in the middle area.
    I cut small saw notches just inside my scribe lines at all 4 corners.
    Note each corner is recessed requiring 4 beginning cuts per corner.
    [​IMG]


    Cutting between two of the shallow cuts makes for a nice straight line.
    [​IMG]


    Next I cut completely through all of the corners.
    The casting in this area about 5/16" thickness
    [​IMG]

    Here you see I used a dull hack saw blade so my cuts were a tad away from the scribe marks
    [​IMG]


    So I then cut the remainder with a thin (1/16") cut off wheel to straighten out my curvy lines.
    Ended up with 3 pieces.
    The middle piece is offal.
    [​IMG]


    After seperation I ground away more excess metal from the boss area.
    [​IMG]


    Only took a couple of hours so far.
    Next it's time to begin putting the two good halves back together.
    So I'll be thinking about it in bed tonight
     
    Last edited: Apr 20, 2017
  9. Apr 20, 2017
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
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    Interesting project Ken, I will be watching this one.
     
  10. Apr 20, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Like I say the original Jeep adapter weighed in at 13-1/2 pounds.
    I'm hoping to trim that number down some.
    For reference the Trans Dapt weights 6-1/2 pounds.
    The AA weighs 6 pounds plus an extra 1-1/2 since it requires the additional sawed off retainer.

    Here I trimmed the top to match the transmission face and I trimmed the bottom to match the proposed front portion of the adapter plate.
    Not shown... I chamfered the adapter's sides and left a penetration gap of 1/16" between the front and the rear plates.
    [​IMG]

    I carefully clamped the two halves back together.
    Side to side positioning was determined by re-alighnment of the cast iron sides.
    Up and Down positioning was done by re-aligning the scribe marks I made before cutting it in two.
    I put the two halves together and spaced them apart with 1/8" thick lead solder.
    Got 4 clamps and began to line everything up while I tightened each clamp a little at a time.
    Thickness is intended to be 1-5/8" or 1.625".
    Set the thickness at each corner to exactly 1.630" so the 2 opposed faces should be perfectly parralel.
    After double checking all measurements I put a big tack onto each corner.
    [​IMG]

    After tacking I removed the clamps and re-checked the thickness measurements.
    It all shrank down from 1.630" to 1.620" thickness.
    Plenty close enough so far.

    For further inspections I fit it between a Dauntless bellhousing and a Borg Warner Jeep T-15 transmission.
    Top view of the proposed adapter in place:
    Note how top of modified adapter matches the transmission face and also the bellhousing.
    You don't see the penetration gap here in this top view because its a fillet weld.
    [​IMG]

    Here's the bottom view:
    After checking this I was satisfied and ready to weld.
    [​IMG]

    Welded with a very old Lincoln AC tombstone welder @ 120 amps.
    Beads required quantity of 5 rods x 1/8" diameter stick electrodes @ 55% nickle composition.
    The welded adapter is now back to a single piece and is 1" shorter than before:
    After welding the 1.620 tacked thickness shrank down as low as 1.610.
    Still plenty close enough concerning thickness.
    I'm thinking that ideally the adapter faces should be milled to near perfect parallel.
    I think they may be as much as .010 out of parallel.
    [​IMG]

    Looking over the welded adapter plate I see what I believe to be even more excess metal:
    [​IMG]

    So I trim the excess and here's my newly fabricated T-15 adapter look.
    Todays effort was roughly an additional 6 hours work.
    And I got the final weight down to 10 pounds.
    That's not too bad for a genuine cast iron part.
    [​IMG]

    One final look of it fitted into the Dauntless bellhousing:
    I love the way the front face indexes directly into the bellhousing bore.
    And the rear face will be indexed via the stock T15 bearing retainer.
    Even though it looks finnished I still need to have the bearing retainer bore increased from 4.25 to 4.686".
    The bearing retainer bore must be perfectly aligned to the bellhousing index bore.
    [​IMG]
     
    Last edited: Apr 20, 2017
  11. Apr 20, 2017
    mortten

    mortten Member

    Peninsula, Ohio
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    Nice work. Pretty ambitious.
     
  12. Apr 24, 2017
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
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    Looking good Ken.
    It will be interesting to see what the total hours & cost comes to.
    Is this a one time project or a prototype for multiple units?
    Oz
     
  13. Apr 24, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Thanks Oz,
    I got about 8 hours total into it right now.
    I still need to get it machined to fit the larger T-15 bearing retainer.
    I might hit up Mcruff for that..... So what do you think Mike ?

    I did it as a 1 of a kind experiment to show that it's do-able.
    The T-14 Jeep adapters are nearly a dime a dozen and this is a good way to get one back into useful service.

    I like the way it can use the original T-15 bearing retainer because this adapter has an index ring to fit into the BOP/GM bellhousing.
     
  14. Apr 24, 2017
    Keys5a

    Keys5a Sponsor Sponsor

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    Very nice work Ken. I wasn't familiar with the T14 adapter, so assumed it was a solid chunk of iron. I should have considered it may be hollow-centered like the T86 adapter plates. Either way, good job on slicing the center out and welding the pieces back together. It still would have expected more movement/distortion from your welding.
    A little more machining will show your persistence pay off!
    -Donny
     
  15. Apr 25, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yes thanks Donny.
    The pre 1971 CJ's with T-86 AA and also the T-14 used the exact same iron adapter plate.
     
  16. Apr 26, 2017
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    I think this is cool, but I wonder if welding the cast iron parts is too much of a barrier for it to be repeated much.

    Great opportunity for someone with the resources to invest some sweat equity. I like the T-15. It's an easy shifter, and in a Jeep, you very seldom need to drop into first. Once you get the rhythm, driving either the T-14 or T-15 around town is a breeze.

    Is it possible to reduce the diameter of the T-15 retainer and avoid boring out the adapter? I've seen this done for some Chevy apps? Maybe use socket head cap screws to reduce the diameter of the bolt heads for clearance?

    :coffee:(y)
     
    Last edited: Apr 26, 2017
  17. Apr 26, 2017
    Twin2

    Twin2 wasn't me Sponsor

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    I have done the same with front of T18 and gm bell
     
  18. Apr 26, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    No the T-15 bearing retainer index diameter cannot be reduced enough to fit into the small 4-1/4" bore of the T-14 adapter.
    Besides, I expect it's critical that the rear bore be made to line up exact with the front index bore.
    And yes the turning down a large T-18 bearing retainer to 4.686 is very effective.

    I know many folks will shy away from welding on cast iron but to me the welding aspect was easy going.
    Simple 55% nickle rod and no expensive welding equipment is require.
    All one needs is average or better skills using stick electrodes.
     
  19. Apr 27, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Here's another thing I did a while back to reduce unwanted weight on a T-15.
    Note the unwanted side shift bosses:
    [​IMG]

    After grinding all that remains is the stiffner:
    [​IMG]
     
  20. Apr 27, 2017
    timgr

    timgr Jeepin' Nerd Sponsor

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    Ken, you must have plenty of time on your hands! :coffee::lol:
     
    ITLKSEZ and Twin2 like this.

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