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71 Jeepster Commando Transmission Swap

Discussion in 'Jeepster Commando and Commando Tech' started by JonAllenTX, Oct 3, 2019.

  1. Oct 3, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    Oct 3, 2019
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    I'm about to purchase a (very rough) 71 Jeepster as a restoration project for my son and I. It has the stock manual transmission/Dana 20 and I don't know if I have the patience to teach my son to drive a stick. I was looking at swapping out the manual transmission for the TH400, but I can't find much in the way of specifics on how to do that and am having a hard time finding a TH400 that's not Chevy. Anyone have any idea of what's involved and/or a good source for the automatic transmission? I've read it's pretty straight forward and easy, but not what is actually involved.
     
  2. Oct 3, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Apr 25, 2019
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    It's a lot of work to do the swap but a good one. Would be cheaper to find another Jeepster with a automatic and rob it OR simply use that Jeepster. The '71 is the best year for a Jeepster Commando that still has the CJ-5 look. Plus the mechanics is better than previous years. Only thing lacking, IMO, is the d30 front end which is offered in the Commandos-'72/'73...a bolt in swap.

    You would need: "BASICS"
    steering column
    steering column to trans linkage
    motor to 400 trans adapter
    early 400 trans-----YOU MAY FIND A BOP 400 THAT THEN WILL ELIMINATE THE MOTOR/TRANS ADAPTER.
    trans to x-fer adapter
    x-fer shift linkage
    drive shafts
    speedo cable
    crossmember??
    E-brake linkage??
    and a lot of patience

    If still wanting to do a auto-----look into the 700r4 non electronic version.
     
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  3. Oct 3, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    Oct 3, 2019
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    Perhaps a dumb question. If doing the shifter on the floor does it still need a steering column overhaul? I was looking at doing the th400 swap with a lokar tailmount shifter to keep the manual look, but the convenience and driveability of an auto.
     
  4. Oct 4, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Apr 25, 2019
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    No steering mod needed with floor shift. You could use the jeepster center console or a simple floor shifter. Please do look over the 700r4 over the 400. shorter in length, lower first gear, 4th gear- like a OD. Also lighter, and about a 30 hp gain over a 400. a 700r4 married up to a d300 x-fer would be one sweet upgrade. I have done this mod in a few jeepsters behind the 225 v-6 and 350 buicks/chevys
     
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  5. Oct 4, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    Oct 3, 2019
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    Thanks Jim! As luck would have it shortly after the initial post I stumbled upon a 70 Jeepster in much better shape that's already an automatic and supposedly runs. Unfortunately, it also has no title and the ID plate has fallen off. So choices to make as I can't afford to pick up both. Need to speak to my local DMV and see how much of a headache it's going to be to try and get a bonded title with no vin. The seller only has the 5 digit engine serial. Hopefully that's enough as I've read folks use that sometimes when all else is missing.
     
  6. Oct 4, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

    Medford Mass USA
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    The sequential serial number part of the VIN should be stamped into the top right front of the frame, near the shock mount. This is how the CJs are, and I presume the Jeepster is the same. You will probably need to wire brush and scrape to find it. The rest of the VIN can be inferred AFAIK. I would ask your registry about whether using that would require a title search ... and you may find out things about the '70 that you don't want to know.

    JMO - as manual transmission cars go, these Jeeps are very easy to drive. Your son might surprise you - when I got my VW at 16, I had been driving for a year and had never driven a manual transmission car. All I knew was what I had observed at 8 or 9 from my Dad and his '61 bug, and understanding the principle behind them ... I just got in it and drove it home. Figured it out on the fly, so to speak.

    As I understand it, the main advantage of the '71 is the steering. Earlier examples have the antiquated Ross steering, and the '71 and later ones have the easier, more accurate and much more durable GM Saginaw steering. Wasn't power steering an option in '71 also? That would be an easy change with Saginaw.

    Expanding on what JeepsterJim says about the TH400 above, there was a TH400 that bolts directly to the 225 V6 that GM used, the so-called BOP (Buick-Olds-Pontiac) case. You would only get this from a GM passenger car. Jeep used an earlier transmission, the so-called nailhead or universal TH400 (named after the "nailhead" Buick engines it was used with), which requires a ring adapter between the transmission and engine. This combo may be hard to source. Possibly you could also use a Chevy TH400 and a plate adapter to the 225. Check on Summit and Jegs - pretty sure they exist and are affordable. The 4.3L Chevy V6 is a popular swap for these Jeeps, and swapping in both the 4.3L and the Chevy TH400 - which bolt together - is another possibility. Regardless, you will need either an aftermarket or Jeep factory adapter between the transmission and transfer case. Check the Novak site for more info.
     
    Last edited: Oct 4, 2019
  7. Oct 4, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    Oct 3, 2019
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    Thanks Tim. Good info. I have been looking at Novak for research and it looks like they have th400s for sale and they'll put all the adapters on it for you for relatively minimal cost. I was thinking that might be worth it. About $2k for a remanufactured auto trans with the proper adapters so I can just bolt it in seems worth it over about $1200-$1500 for a rebuilt and I'll still need to source the adapters.

    Good to know about the VIN stamp. I'll have to see if I can find it. I believe it's an 8701 convertible as it appears to have the rear quarter window spots (the windows themselves are long gone though). My understanding is the roadster versions do not have those windows. Can't tell from the interior as it's been stripped and since tossed in the trash. :shock:/
     
  8. Oct 4, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Carefully look at the trans to x-fer adapter....if memory serves me, the crossmember is bolted to it. The bolts like to loosen up and strip out the adapter that hold the trans .
    If possible, you can remove the metal rectangle VID plate...mounted on firewall, simply switch out the plates TADA.
     
    Last edited: Oct 4, 2019
  9. Oct 4, 2019
    Keys5a

    Keys5a Sponsor Sponsor

    Florida Keys
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    If you believe the one Jeepster is a true convertable, there should be evidence of the beltline trim about 6" down from the top edge of the body, also wrapping around just below the windshield.
    As far as the Th400 to D20 adapter, there is not only the alloy cast adpter, but also a unique splined tailshaft out the back of the actual 400 trans.
    -Donny
     
  10. Oct 4, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Does it have a functional tailgate??? or have a deck lid on top?
     
  11. Oct 6, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    Hey guys, sorry I was camping with my son this weekend, the seller finally found the serial plate which he swore had fallen off. It's an 8702 017, so it's the Jeepster Commando Convertible, but not the two tone Jeepster Convertible with the deck lid. I was also able to get the DMV to look up the title with the full serial. It's labeled as a 1970 in the ad, but title is a 1971. Once I get up there to see it (6+hr drive one way) I'll have to find the steering gearbox and see if it's a Ross or Saginaw.

    Things are looking up. :)
     
  12. Oct 6, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Glad you found the ID plates!

    the commando convert was made '69 &' 70. People were complaining about not having access to the rear area. Np functional tailgate. Sounds like kaiser reregistered it as a '71. Kaiser/Willys did this a lot and got spanked hard for it in'71????? Lets hope you have sag steering and a flanged d-44 rear diff.
     
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  13. Oct 7, 2019
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    I agree! My son wants to be able to wheel it (we're a Wrangler family), so it's going to end up more of a restomod vs a straight restoration. He chose a Jeepster because he wanted something unique that not many people have, but still wants a Jeep. So the plan is to restore it for now and replace as little as possible. Get it cleaned up, body work, running really well, add some modern touches like AC and a stereo with GPS, small lift and 31-33" AT or MT tires, etc. Maybe a power steering upgrade, if it doesn't have it. Once he's 16 and learns to drive well enough he can handle offroad driving I'm looking at upgrading the D-27AF to a D-44 and possibly regearing the diffs (depending on if it has the 3.31 or 3.73 ratio) and getting the Jeepster more in touch with his CJ5/CJ6 brethren, while trying to maintain what makes a Jeepster a Jeepster. :) There will be a delicate balance. As far as the rear diff goes, if it's the D-30 or tapered D-44, I figure worst case is I'm doing front and rear at the same time. I'm planning to add lockers anyway, so the bump in cost between regearing and adding a locker to the existing diff and replacing the whole axle with a diff that already has the gearing I want and a locker isn't huge in the grand scheme. Plus, I'm also waiting on it until he takes ownership of it because at that point, if he wants it he's paying for it. Or at least half of it... Whatever is on there stock should, hopefully, be good enough for cruising around town and test drives during the build. Lots to do before I get to that point anyway.

    If anyone is good a deciphering the serial numbers it's 8702 017 51219. I looked through the VIN thread, but I didn't see any 8702s so I can't place the year. Just know it's the Jeepster Commando Convertible with smog package. I guess this model is a little more rare than many? I thought the 8701s and 8705 Hs were the most rare. I was surprised not to find any 8702s.
     
  14. Oct 7, 2019
    mikieboy

    mikieboy Member

    Jacksonville, FL
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  15. Oct 16, 2019 at 12:13 AM
    Keys5a

    Keys5a Sponsor Sponsor

    Florida Keys
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    The front 27a axle isn't that bad, but a Dana 30 narrow track front axle is way better, and essentially bolts in. The 30 is way easier (and cheaper) than a custom 44.
    -Donny
     
  16. Oct 16, 2019 at 1:25 AM
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    D30 is the way to go. '72-'80. '77/'78 has the best disc brake system
     
  17. Oct 19, 2019 at 11:30 PM
    JonAllenTX

    JonAllenTX New Member

    Round Rock TX
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    So 77/78 CJ narrow track D30 disc is basically a bolt on replacement? Obviously aside from the changes to the brake system to account for the disc/drum setup.
     
  18. Oct 19, 2019 at 11:55 PM
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    yup----may need new u-bolts but they should be replaced any way. also "some" d30's had a different sized yoke----all easy to do and well worth it.
     
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