Borg Warner T98-a

Discussion in 'Early Jeep Restoration and Research' started by oldtime, Jun 5, 2017.

  1. Jun 5, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Due to request and a need to document pics before it's too late.

    Beginning in the 1956 model year the Heavy Duty T98-A became an option for models CJ-5 and CJ-6.
    I prefer to think about it this way...
    This was the very first and remains as one of the very finest rock crawling tramsmissions ever installed into any 4WD.
    With this transmission installed into the a Jeep the "rock crawler" was born !


    In this very first pic we see an inside look at a 1956 T98 -A in original near pristine condition.
    [​IMG]

    Signs of severe internal wear typically occur on the rear toothface of the 1st/ Reverse sliding gear.
    The teeth will grind when jammed into the non synchronized reverse gear which causes broken and chipped teeth.
    [​IMG]

    This T98-A 1/st reverse sliding gear is one of the very finest I have seen.
    [​IMG]

    Left: Here you can see that it is in previously repainted but unrestored condition.
    Note the case bulge near the rear.
    All T98 and all pre 1980 T18 transmissions cases use this same case.
    With alll Jeep T98 and T18 cases the PTO port is on the left side
    [​IMG]

    Right: The 2 uppermost threaded lugs were used for non CJ applications and so they are plugged with bolts.
    [​IMG]

    Front:
    Note: the massive sized bearing retainer.
    The original front bearing (unseen) is an MRC 308 SG -2
    The thickness is due to the need for a front adapter plate.
    The retainer also provides the socket for the clutch release lever fulcrum ball.
    The sleeve diameter of the bearing retainer accepts the standard Willys 134 clutch release components
    The maindrive gear pilot tip fits the standard 134 flywheel bushing
    8-1/2" and 9-1/4" diameter clutches will fit onto the 15/16" / ten spline maindrive gear
    [​IMG]

    Rear
    Here you see the common Jeep 1-3/8" diameter 6 spline mainshaft.
    The T98's use a cottered nut to fasten the mainshaft gear where the later model T18's use an ESNA nut
    The countershaft and reverse shaft lock plate is bolted into place.
    This transmission was not designed to share lube with the transfer case.
    The large bushing seen on the mainshaft behind the mainshaft bearing is sealed.
    Original rear bearing is a large MRC 308 SG.
    [​IMG]
     
    Last edited: Jun 24, 2017
    73 cj5, timgr, BJHitson60 and 2 others like this.
  2. Jun 5, 2017
    1957Willys

    1957Willys Member

    Birmingham, Alabama
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    Do you have any pictures of the drive shafts and pictures of the transmission installed in a CJ5 with the floor pans removed?
     
  3. Jun 6, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yes I do have other T98-A pics that I'll upload as soon as I get there.
    No pics of the T98-A before it was removed.
    i removed it all myself so I will document some of that detail.
    In case you have not seen this is what I posted about it a couple years ago.

    What You Need
    Ken Bushdiecker provided some detailed information:

    "The T98-A was introduced as a CJ-5,6 option in 1956. The installation includes the following parts. Most but not all of these parts are needed for CJ-3B conversions."

    10.22 Flywheel Housing

    • # 910467 Plate, adapter, bellhousing to transmission (7/8" thick cast iron) (qty. 3) Bolt 9/16" - 12 x 1-3/4" (qty1) Bolt 9/16" - 12 x 1-1/2"10.23 Engine Mounting
      • # 912721 Insulator, engine support rear
      11.02 Clutch Control Parts
      • # 911681 Bracket, clutch control frame
      • # 911602 Cable, clutch control lever (OAL is 13-5/8")
      • # 911600 Lever and Tube, clutch control (8-1/2")
      • # 923636 Lever and Tube, clutch control (9-1/4")
      • # 911603 Rod, clutch release pedal (8-1/2")
      • # 923640 Rod, clutch release pedal (9-1/4")
      • # 911680 Stud and bracket, ball clutch control assembly
      13.01 Exhaust System
      • # 913454 Extension, exhaust pipe
      • # 803680 Insulator, support
      • # 913456 Pipe, Exhaust assembly
      • # 913457 Support, exhuast system assembly
      16.04 Speedometer
      • # 913035 Tube and shaft, speedometer (OAL is xx")
      17.01 Transmission
      • # 911216 Seal, oil, adapter plate
      • # 910468 Plate adapter, transmission to transfer case (7/8" thick cast iron)
      • (qty 4) Bolt 3/8" - 16 x 1-1/4"
      • (qty 2) Bolt 7/16" - 14 x 1-3/8"
      • # 911215 Spacer, (mainshaft output)
      • # 911627 Transmission assembly (T98-A)
      17.06 Gearshift
      • # 914183 Knob, transmission control lever
      18.02 Transfer Case
      • # 911598 Case, transfer assermbly (the complete transfer case assembly has special shaped shift levers and shift pin as noted below)
      • # 913085 Cap, bearing output clutch shaft
      18.06 Shift Lever
      • # 911862 Lever, shift, front wheel drive
      • # 911861 Lever, shift, underdrive
      • # 913159 Pin, pivot lever, shift (this shift pin is slightly shorter than the typical shift pin)
      • # 941729 Assembly, single lever (this is only for post 1967 with single stick transfer case)
      18.08 Transfer Case Mounting
      • (qty1) Bolt 3/8" - 24 x 1-1/2"
      • (qty1) Bolt 3/8' - 16 x 1-1/4"
      • (qty4) Bolt 3/8" - 16 x 1-1/8" (qty4) lock washers (1) hex nut (1) jam nut
      19.01 Propeller Shafts
      • # 915949 Propeller shaft, front assembly 28-1/4"
      • # 918339 Propeller shaft, rear assembly 13-7/16"
      24.01 Hand Brake
      • # 911693 Cable and conduit, front assembly (69 -3/8" for 4 speed with Tee brake)(4" longer than standard)
      26.01 Frame
      • # 911622 Crossmember support, engine rear
      • (qty4) Bolt 3/8" - 24 x 2" with nut stop elastic
      • # 911713 Plate, skid under frame
      • # 913057 Spacer (engine rear crossmember support) (1" thick white oak)
      31.09 Floor and Underbody
      • # 694643 Pan, front floor assembly
      • # 968335 Pan, front floor assembly (for post 1966 single shift transfer case)
      31.14 Plates, Seals and Covers
      • # 948185 Boot, gear shift lever (for post 1966 single shift transfer case)
      • # 694579 Plate, cover front floor pan opening assembly
      • # 694572 Plate, cover lower front floor pan
      • # 695543 Plate, cover transfer shift opening
      • # 694623 Spacer, gas tank
     
    Last edited: Jun 17, 2017
  4. Jun 6, 2017
    Danefraz

    Danefraz Sponsor Sponsor

    Chico CA
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    Excellent details. May be we can get it added to the tech index.
     
  5. Jun 6, 2017
    pfmg

    pfmg Member

    Billerica Mass
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    great info, thanks...now someone find me one to put behind my fhead?
     
  6. Jun 6, 2017
    Dave B

    Dave B Frankenjeep '67

    Northern Minnesota
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    I have the T98 (not the T98a--I believe) transmission conversion in my 1967 CJ5 225 odd-fire V-6 with a Warn overdrive. The T98 is a heavy-duty, top loading, truck style four-speed. Very similar to the transmission I had in a 1958 Ford 1-ton stake-bed truck.

    In low on a steep downhill the transmission will hold the CJ5 under 1 mph, and in 4th & overdrive it will run the highway at 65 mph and faster--but I'm not really comfortable running at speed. Life is short enough without trying to make a speedster out of a lifted CJ5.

    The Novak Guide to the Borg-Warner T98 Transmission
     
    Last edited: Jun 6, 2017
  7. Jun 6, 2017
    wheelie

    wheelie beeg dummy Sponsor

    York, PA
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    Ken,........question.....you say, in your description of the last picture, that...

    "The large bushing seen on the mainshaft behind the mainshaft bearing is sealed."

    How is it sealed? My T18 (I know, slightly different animal) has this bushing but, no type of seal is apparent to me other than the seal that goes in the adapter plate........or is this what you mean. The seal I'm referring to rides on the O.D. of this bushing. It's the only seal I am aware of for this area.
     
  8. Jun 6, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yes Dave, that's exactly what I meant.
    In fact the T98-A mainshaft bushing is identical to the Jeep T18 mainshaft bushing.
    The bushing rides the inner seal face of seal that is pressed into the rear adapter plate.
    Oh so I guess that's my cue toward the rear adapter plate..................

    On your left you see the foreward face of the bellhousing adapter plate which bolts to the Willys 134 bellhousing.
    On your right you see the foreward face of the Dana 18 adapter plate.
    You can see the seal that rides the outside of the mainshaft bushing.
    Both of these adapter plates are 7/8" thick.
    The T98 and T18 transmissions have no provision for mounting the rubber insulator.
    The rubber insulators mount at the flat narrow bottom of the rear adapter plate.
    [​IMG]

    On your left you see the rearward face of the bellhousing adapter plate.
    The 4 large bolts fit the T98 transmission pattern and the 4 bolt holes match the Willys 134 bellhousing.
    On your right you see the rearward face of the Dana 18 adapter plate.
    You see the 6 bolts used to fasten the plate to the transmission and the usual 5 bolts required to attach the Dana 18 to the plate.
    [​IMG]

    You can see how the rear is indexed into the transfer case via the protruding ring.
    This ring is specific for small hole transfer cases (3-5/32" index bore)
    Jeep T18 transfer case adapter plates are identical except they have a 4" bore ring.
    You can also see how the T18 adapter (on the right) is still marked as T98-A
    [​IMG]

    Here you see the top of the shift tower assembly.
    Note that the 2 bosses seen extending out to the right side that are not used for CJ applications.
    Also note that unlike later T18 shift towers there is no place for a reverse light switch.
    [​IMG]

    Here you see the working side of the shift tower assembly.
    Note that whenever removing or installing any transmission shift tower, the transmissions gears and the forks should both be in neutral positions.
    The large fork on your right fits into the 1st/reverse sliding gear.
    Now note that the top rod has no shift fork.
    That rod's "slot" fits onto the reverse shift lever as seen in the T-98 inside top view.
    Also note how these early T98's were safety wired instead of having the later design allen head screws.
    Finally note that the shift forks are of solid cast iron without the late type plasticized tips.
    [​IMG]

    If anyone has further questions feel free to ask otherwise I'll move on to other Willys components used for Borg Warner T98-A installation.
     
    Last edited: Jun 13, 2017
  9. Jun 6, 2017
    1957Willys

    1957Willys Member

    Birmingham, Alabama
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    Do jeeps with the T98 transmissions use the same skid plates?
     
  10. Jun 6, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    No they do not.
    They are much larger than standard skid plates.
    I'll get to that with pics a little later.
     
  11. Jun 6, 2017
    Keys5a

    Keys5a Sponsor Sponsor

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    In your opening post, you state the example transmission is "in original near pristene condition". I think that is an understatement; that thing looks brand new inside! I've never seen one without rounded off teeth from the lack of syncros.
    Great thread showing ALL of the unique parts for installation in our early Jeeps.
    -Donny
     
    Last edited: Jun 7, 2017
  12. Jun 7, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yeah Donny, it's exceptionally clean inside. Zero rust spots.
    I was going to take a close up of the gear teeth but have not done so yet.
    Here below is a close-up of a Ford T18 1st reverse slider gear.
    It's in a more typical condition and likely a tad better than average.
    I've seen many T98/T18 1st/reverse slide gears that were especially chewed up.
    [​IMG]
    [​IMG]
     
    Last edited: Jun 13, 2017
  13. Jun 8, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    8-1/2" or 9-1/4" diameter Borg Beck driven disks will fit onto the 15/16" / ten spline maindrive gear
    [​IMG]

    There are 2 different clutch control "lever and tube" assemblies designed to fit T98-A with the above clutch sizes.
    The pedal shaft release rod which measures 13-3/4", pin center to pin center.
    Plus the special length release cable that is for use with the Willys T98-A.
    The T 98-A release cable measures 13-5/8" OAL from ball end to threaded end.
    The release fork itself and the release bearing carrier assembly are standard Willys parts.
    [​IMG]

    For a broader comparison here is the complete batch of early CJ clutch control "lever and tube assemblies" .
    The combinations are determined by clutch make, clutch size and the transmission installed.
    You see that the 2 used for T98-A installation require less width.
    [​IMG]

    Jeep T98 and T18 clutch control ball pivot studs always thread into the side of the rear adapter plate.
    You also see the original # 912721 Insulator
    [​IMG]
     
    Last edited: Jun 17, 2017
  14. Jun 8, 2017
    1957Willys

    1957Willys Member

    Birmingham, Alabama
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    What are the dimensions of the of the lever tube for a T98 transmission with a 8-1/2 clutch? Length end to end and how far are the levers spaced from one another?


     
  15. Jun 8, 2017
    wheelie

    wheelie beeg dummy Sponsor

    York, PA
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    Now there's something I hadn't considered. (sorry...I love that line). Never gave a thought to torque tube lengths and control cable lengths and stuff being different. Great information here, Ken. Thanks for sharing it all with us.
     
  16. Jun 10, 2017
    1957Willys

    1957Willys Member

    Birmingham, Alabama
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    This CJ5 has a Kubota installed but is this how far the T98 sits back? And there is a big difference between a T98 and T90.

    T98 CJ5.jpg T98 vs T90.jpg
     
  17. Jun 10, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Note: I call them "lever and tube assemblies" because that was standard Willys terminology
    I define the 2 distinct levers of each assembly as the pedal shaft lever and the release fork lever.

    All CJ's used a tube that is 5/8" I.D. by 7/8" O.D.
    The tubes 5/8" I.D. always fits over/onto the stud ball pivots.

    Both of the T98-A lever and tube assemblies are 6-1/2" OAL (wide)

    I measure each of these lever for throw length, from outside the 7/8" tube to the center of the clevis hole.
    For 8-1/2" T98-A the pedal shaft lever throw length is 2".
    The release fork lever throw length is 1-3/8".

    Each lever is also be measured its position along the length of the tube.
    I measure this from right end of tube to CL of each lever.
    The pedal shaft lever is centered 1" from right end of tube.
    The release fork lever is centered 5-1/2"" from right end of tube.

    The levers are clocked toward specific locations.
    I describe the lever clocking position as you observe the lever and tube assembly from the right side
    (pedal haft lever is closest and release fork lever is farthest away)
    The pedal shaft lever is clocked to 6 PM
    The release fork lever is clocked to 1 PM

    I'll comment on T98-A sheet metal concerns a little further along.
    Next I will address the subtle changes for the transfer case.
     
    Last edited: Jun 10, 2017
  18. Jun 13, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    Transfer case for use with T98-A is same as all other 2.46 ratio post 1954 small hole cases with 2 exceptions.
    The modified front bearing cap and the shorter shift pin.
    Standard shift pin is 3-1/4" and T 98 shift pin s 3" long.

    Here's the T 98 front bearing cap top view.
    [​IMG]

    This part is identical to standard, except one side has been narrowed in order to clear the wider transmission.
    From the factory about 1/4" width was removed on your right.
    [​IMG]

    Side view shows how it was milled off:
    [​IMG]

    The transfer case itself sets upon a factory modified rear engine support crossmember:
    Here again you see where to locate the # 912721 Insulator.
    2-1/8" represents relocation back from standard center of crossmember
    Note how T98 remains in same Right / Left position as T90 transmission.
    You may also notice the two holes for standard parking cable clamp on your right.
    Two additional holes were added on left side to accomadate the special longer parking cable.
    Unlike the T90, the longer T98-A park cable goes to left side of transmission.
    [​IMG]


    The T98-A cross member requires use of 1" inch thick oak spacer blocks and longer bolts
    You can see these blocks (unrestored condition) were factory painted black.
    [​IMG]

    And now here's that original # 911693 Cable and conduit:
    [​IMG]

    Note: Because this cable goes around the left side it requires that the transfer case park brake lever be of the late type (longer) design shown here:
    [​IMG]
     
    Last edited: Jun 15, 2017
  19. Jun 13, 2017
    wheelie

    wheelie beeg dummy Sponsor

    York, PA
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    Is # 912721 Insulator still available anywhere (not Omix). When I finally get my T18 in, I'll need this or I'll use some other type of mount or bushing. I'll probably make my own cross member.

    It appears that the added piece on the cross member, where the trans mounts, is lower than the original mounting area. Is this so?

    And pictures of that late model brake lever. I don't think I've seen one with multiple holes, at least not that I specifically remember.
     
  20. Jun 14, 2017
    oldtime

    oldtime oldtime

    St. Charles,...
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    The 912721 insulator is not too common but is still available new..
    I can take a pic of a later version that was used on a T18 if you wanna see a little variation.
    I just happened to take a few more pics of those items this morning.

    In this view you can see that the original location for transfer case snubber remains unchanged.
    That's basically because the engine and its Right /Left positioning remains unchanged.
    [​IMG]

    Here's another view of the T98 addition to the standard rear engine support crossmember.
    This extended platform sets about 1/8" below the original support height.
    [​IMG]
    [​IMG]

    Dave,
    IMHO This particular engine support crossmember will not fit properly for T18 behind a Dauntless.
    I believe that a distinct rear engine support crossmember (transmission crossmember) should be used for each individual combination of engine, transmission and transfer case.
    Jeep had a bad habit of re-using the original rear engine support crossmember to address all of those variables.
    A crossmember that may be ideal for a Willys 134 and T98 is certainly not ideal for a Jeep with Dauntless and T18.
    There are many measurements that change whenever one switches engines, transmissions and or transfer cases.
    I have done some research into fitment for specific drive train combinations.
    If you care to read far into that thread, it may be helpful.

    http://z4.invisionfree.com/CJ3B_Bulletin_Board/index.php?showtopic=6717

    Do you have a build thread on your Jeep with T18 ?
     
    Last edited: Jun 15, 2017

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