What tranny would you use behind a 7.3 NA

Discussion in 'Diesel Tech' started by mike Moran, Sep 11, 2007.

  1. mike Moran

    mike Moran Farmall Cub

    hi all,
    Acquiring a 89 7.3 NA from a S1600 medium duty truck with 152k. The tranny is blown so my buddy is giving me anything i want off the truck. I already have the engine unbolted and will be yanking it this week. Any known problems with this engine?
    My intention is to put it in a 70 1200 Travelall. What tranny would you guys use?. Should i take the bellhousing too or is that only good for the monster 5 speed that its hooked to now. I am open for all suggestions. Fabricating is the fun part as I did when i put the mercedes 5 cylinder in my 73 travelall that is now a wagonmaster. That has been about 3 years i guess and is my daily driver. Runs great on veg,diesel or whatever and gives me 20 mpg consistently.
    If i went with an automatic is the c-6 my best bet or could i use one with an overdrive?. Whatever is the concensus i will start lookin for a wrecked complete vehicle. I find its best to have the donor vehicle at hand when doing this stuff.
    thanks Mike
     
  2. John Donnelly

    John Donnelly Administrator Staff Member Administrator Moderator

    Given some recent experiences with a Ford F-250 with a 6.9L and a C-6, I would opt for a manual transmission wherever and whenever possible.

    Ford, Diesel, and Automatic just don't seem to meld well.

    I would get the bellhousing and the clutch from the S-series also. It will expand your transmission options for certain.

    -John
     
  3. cartwright

    cartwright High Wheeler

    I would use a ZF 5 or 6 spd.
     
  4. WRENCH MAN

    WRENCH MAN Y-Block King

    I wouldn't, I would use a cast iron tranny.

    What's wrong with the tranny out of the S1600?
     
  5. CareyWeber

    CareyWeber Diesel Herder / Moderator Staff Member Moderator

    Nothing wrong with them, but the ZF Five and Six speeds have been proven to be good tranys in trucks up to Ford F-550 with Power Stroke @ much higher horse power levels than the 7.3 NA will ever have.

    If it was going in a Truck like a 1600 or up I'd say stay with a mediem duty truck trany, but in a Travelall I'd get a ZF.

    Carey
     
  6. truck mechanic

    truck mechanic Binder Driver

    Hey Mike
    I am looking at the same swap for my pick up. I have a na 7.3 and a zf 5spd. I am going with that set up. I would love to do an auto but have pulled to many of those to count. Just keep in mind you will need the addapter that goes between the motor and trans from a Ford.
    Paul
     
  7. mike Moran

    mike Moran Farmall Cub

    thankyou to all for the respones. Seems that the zf 5 speed might be the way to go. I will start my search for one in my travels.
    As far as the tranny in S1600 now it is blown. That is what took the truck off the road in the first place. My friend was quoted a price of 4,500$ to fix it and he opted not too because he was buying a new truck anway.
    I also like the sugestion of a Allison 545. Seems that many school busses came with them and it should be more than able to push a travelall down the road.
    Would anyone know what model tranny is in that S1600 now. I believe it is a 5 speed?
    Mike
     
  8. MarkO

    MarkO Farmall Cub

    Since you are having to purchase a transmission anyway, why not purchase a used school bus and use everything out of it--engine, transmission, wiring harness, motor mounts, transmission mounts, etc.

    There are whole fleets of IHC conventional buses on the market with the T444/T444E or the DT360 out there with good power packages. Since you are in the rust belt you won't care if the body is shot which should lower the price considerably. Around here, a good running used school bus is going to cost about what you would have to pay for a new or good used transmission (I purchased a good running IHC/BB bus with the 6.9/AT540 for $1500.00 and a good running IHC/Carpenter with the DT466/AT643 for $1500.00). In addition, you would get all of the parts and pieces to make your new power package work.

    At the end of the project you would have either a really ugly storage shed or about 5 tons of scrap at $100 per ton.

    The Allison AT500 series transmission in a light line vehicle would be real overkill. With the proper cooling system you would be hard pressed to ever hurt it. The only downside is it would not have a park position in the transmission. But if you were to get the power package out of bus with hydralic brakes it would come with a medium duty truck sized driveline emergency brake.

    The Allison AT500 series uses a direct drive top gear. Since it has 4-speeds you should be able to put some real highway cruising gears in the rear end and still have some first gear grunt power.

    Just my two cents worth.

    Mark O.
    Castle Rock, WA
     
  9. Jim Grammer

    Jim Grammer Editor at large Staff Member Moderator

    Spicer 52xx series is one likely suspect.
     
  10. IHWillys

    IHWillys Farmall Cub

    Another option is the T3x IH 5-speed transmission. I have almost all the parts for this.

    Parts needed to do this:
    - SAE#2 flywheel housing for 6.9/7.3 IDI
    - SAE#2 clutch cover(trans adapter) for IH T3x transmission
    - Starter
    - Flywheel
    - Pilot & throwout bearings
    - clutch disc/pressure plate

    I have the first 3, and possibly the last 2(will have to wait and see after I get a flywheel).

    Atleast one caveat learned thus far: There are 2 different sizes of indexing circle for the starter on the flywheel housing, obviously the starter and housing need to match on this point. I suppose because they use the same bolt pattern a small circle starter could be used on a large circle housing with a ring used to center the starter.

    I like this option for several reasons. One is the inexpensive aspect of the IH T3x transmissions. I have several and the most expensive was a rebearinged T34(OD) at $500. The others were less than half that, one of which is a freshly rebuilt T35(DD). Another reason is that one can easily change from one set of ratios to another by swapping in another model of the T3x transmission. The T35 is a nice set of ratios for a pickup truck diesel as it provides what a close ratio Warner T19 offers plus a 'granny' 1st and reverse and T36 is even 'closer', all in a cast iron case that is an IH product. No they don't shift like the newer transmissions, they're definitely more truck-like. Also the throw-out is done the same way in the SAE clutch cover as in the lightline gasser bellhousings. So swap the throw-out cross shaft from an IH gasser bell into the SAE clutch cover and the stock external clutch setup works for swaps of IDI into lightline vehicles(provided clearance, etc).

    If anyone sees fault with my assessment please "speak up" as I like to learn as much as I can before going the school of hard knocks route.

    Ken
     
  11. John Donnelly

    John Donnelly Administrator Staff Member Administrator Moderator

    You can also use an IH MV bellhousing if you don't have the SAE stuff.

    -John
     
  12. WRENCH MAN

    WRENCH MAN Y-Block King

    They must pump them up harder out here on the west coast!? and with the 36"+ tires and stock gearing pulling the WAY over loaded tripple axle fifth wheel trailers up the MOUNTAIN passes at 70mph they will AND DO FAIL!
    Not to mention that's why Ford went to that POS "dual mass" fly wheel, the ZF's were getting beat to crap just from the pullses of the diesel, the T-19's didn't need it!
     
  13. stu simpson

    stu simpson High Wheeler

    Surely you have a Transaxle location near you. I have had them either rebuild or exchange for a rebuilt transmission(s) for several medium duty trucks. I don't think the bill was ever more than $1,500. The Clark 455-5 out of the GMC was about $1,350. That hasn't gone up in 10 years. The Spicers weren't much more than that. If they don't have one in, they can get it in 2 or 3 days or have yours rebuilt by the end of the week. Add $1k to that if you ever need that Allison redone. If you go ZF, go with a new solid flywheel conversion kit from Luk etc from an online dealer and save yourself the rattle. The whole kit is about $600 and that includes the clutch pieces.
     
  14. CareyWeber

    CareyWeber Diesel Herder / Moderator Staff Member Moderator

    The bad part of most Allison AT is no lock torque converter (yes I know the 1000 used behind the Duramax locks up).

    They are strong, but hte no lock up will kill the MPG.

    Carey
     
  15. KollenH

    KollenH Farmall Cub

    Mike,

    Is your Travelall 2wd or 4wd? Apologies if I missed that somewhere in all the posts. If 4wd you'll run into some transfer case limitations with the ZF. The only thing that bolts up to one is the stock BW which drops on the wrong side, or a D300 with an adapter but nobody really feels it would live in a full-size rig behind a diesel.

    If it's a 2wd, lots of options. Sticking with a ZF will be the easiest and they are a nice shifting transmission with a .78 overdrive for good cruising. It will hold up just fine in a stock rig. The dual mass flywheel is expensive but there are solid mass replacements available in the aftermarket. Another option is the NV4500 which easily adapts to the 6.9/7.3 and is plenty strong. It has a wider gear set with a lower 1st and taller 5th (0.73) than the ZF with cheaper/easier rebuilds as well.

    Hope this helps you.
     
  16. CareyWeber

    CareyWeber Diesel Herder / Moderator Staff Member Moderator

    The great thing about the IH full size rigs Trucks and Travealls is the divorced transfer case which means you can run a two wheel drive ZF so no adapter is needed just get the drive shaft with the trany.

    Carey
     

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