A883 in a Buick?

Discussion in 'U-shift em' started by knucklebusted, May 1, 2016.

  1. knucklebusted

    knucklebusted Well-Known Member

    A833 in a Buick?

    There is an A833 manual that is a 3.09 first and .73 overdrive for sale here. It says it has a Buick bellhousing. I'm wondering if this will fit in my 71 350 4 speed and 3.08 rear with minimal change? I'd settle for an M20 to replace the M21 but if I do that I don't want to change clutch or drive shaft and I have the later M21 which is fine spline input and large output shaft. I find lots of M20s but they are all course input shaft and small output shaft.

    About all I can find is this is a truck transmission from 2WD manuals in the 80s. Anyone have experience with these? Will it survive behind a stock 71 350?
    Last edited: May 2, 2016
  2. flynbuick

    flynbuick Guest

    A833s are much tougher trans than Muncies. They used various input and output shafts depending on the year model and the power plant. So you need to ID what you may be buying.

    I use Brewer for A833s:
  3. Gulfgears

    Gulfgears Gulfgears

    This caught my eye, and after doing a few quick searches found out these things sell for around $250-$400 even on E-Bay.

    What are the problems one would encounter fitting one in a 300 Buick. I'm assuming that the input shaft dimension may be a problem, or the transmission bolt up may not be right, and obviously the yoke would be a different one meaning driveshaft work. Plus fabbing a cross member.

    But, when a 5 speed can be $1500 and a six speed can go for around $4000 when all said and done, this A833 od looks like it might be doable.

    I would really like an od manual transmission, but just can quite justify what I've been able to find so far. I have a friend who has a machine shop so any machining work might be doable also.

    It appears that these od boxes were used in vans as well as pickups, but I'm not sure of what model years they were available for.

    Any input, pros/cons?
  4. cstanley-gs

    cstanley-gs Silver Mist

    I have an M20 from a 72 corvette.
    I believe 71+ Muncie will be fine spline in and out
    Im using the same driveshaft.
  5. knucklebusted

    knucklebusted Well-Known Member

    You are using the M20 or have one you would part with?
  6. 87GN_70GS

    87GN_70GS Well-Known Member

    Is it an iron case or aluminum case? Iron case is stronger, but both should be fine behind a stock 350
  7. cstanley-gs

    cstanley-gs Silver Mist

    The M20 is in the car now
    Funny story, the guy I bought it from over 2 years ago just called a few months ago and asked if he could buy it back :puzzled:
  8. knucklebusted

    knucklebusted Well-Known Member

    I've been looking for a compatible M20 but they are either expensive or junk. This A833 looks like the holy grail for a poor boy with too high first gear (2.20) and too high rear gears (3.08). That 3.09 first gear in the A833 makes it like 4.33 rear gears. VERY NICE! I often skip 2nd or 3rd, depending on the last gear I was in when up shifting.
  9. sodak65

    sodak65 Well-Known Member

    This is an aluminum case Chevy truck trans. It has the standard Muncie course spline input/ th350 output. It has been modified for car use by turning down th front bearing retainer to fit the standard GM car bellhousing and the input shaft is designed to fit a retrofit pilot bearing so it will work with any crankshaft. The pilot bearing bearing,yoke and bellhousing are included. No this is not a tremec tko600 but it is a nice light overdrive that physically fits right in place of a standard 4speed or th350 and has virtually identical gearing to a 700r4.
  10. knucklebusted

    knucklebusted Well-Known Member

    Nice, I look forward to the shipping info.
  11. knucklebusted

    knucklebusted Well-Known Member

    Anyone done this? What shifter arrangements did you use if you didn't have the original shifter, rods and arms?

    My welding skills are non-existant so I'm hoping for something that can be cobbled together pretty cheaply/easily.
  12. sodak65

    sodak65 Well-Known Member

    I was going to make rods out of steel rod that can be threaded and rod ends on both ends. the shift bolts to the trans with spacers.

    Attached Files:

  13. philbquick

    philbquick Founders Club Member

    You can convert your M21 to an M20 by changing the input and cluster gears. Yes, a M21 with a 3.08 rear is a bad combination. Overdrive would be better with a 3.42.

    I didn't know about the A883, I need to check it out. Sounds like the machining is minimal. Wish I had known about that when I had my Vette.
  14. stew'86MCSS396

    stew'86MCSS396 Well-Known Member

    The thought has crossed my mind some years ago while searching for a cheap OD alternative. I printed out some articles, unfortunately one of them (Auto Hobby Digest) has lost it's hosting. Here's the link to the one's I could find: http://www.slantsix.org/articles/4-speeds/ODA833fourspeed1.htm and http://enthusiast.yearone.com/vehicle-info-decoding/mopar-decoding/4-speed-transmission-decoding/ Still alot of information on the web if you do a search. Anyhoo, GM RPO code is MY6. IIRC, the OD design makes this trans torque limited. Back then, if I were to run one, I was inclined to using the non-overdrive unit with the 3.09 1st or finding the right cluster to convert an OD unit back into a non-OD one. I've ran a Saginaw 3.10 1st with a 2.73 LSD rear, not very exciting but it was still fun street romping it. :3gears:
  15. Brent

    Brent Well-Known Member

    The GM A833 variant was used in trucks from about 81 to 86. They came in both cast iron and aluminum cases, all had aluminum extension housings, as stated above have 10 spline inputs and 27 spline outputs and are the same length as a th350. Very strong especially the cast iron one, way better than a Muncie. I have ran several and used them in other peoples cars. I had one behind a turboed 455 making over 600ftlbs of torque at the wheels. The ONLY down side is the gear splits are huge, big jump from 2nd to 3rd. Big Blocks seem to handle this ok but with smaller motors it might be objectionable. The cast iron case has a weird hybrid GM/Mopar bolt pattern so it requires some fab. The aluminum case is all GM and bolts right up. Get it if you can they are awesome. Be certain you are getting a GM one and not a Chrysler one when you buy.
  16. knucklebusted

    knucklebusted Well-Known Member

    The pics look GM and he has a BOP bellhousing with it. I posted pics he sent me in the for sale section but here they are again. The shifter is my only concern. I'm not a welder and would need to get a shifter cobbled together but I don't figure it is out of the realm of possibility. The M21 with the 350 and 3.08 gears is way high on takeoff. I often skip 2nd or 3rd so the gear splits don't seem like a big issue.

  17. stew'86MCSS396

    stew'86MCSS396 Well-Known Member

    I don't remember what the one I've came across eons ago...seem to remember that hybrid Chebbie/chrysler mount pattern that was mentioned...

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