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Aluminum case OD A833 for E body?

Started by gzig5, October 18, 2018, 02:35:36 PM

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gzig5

Any reason to avoid an aluminum cased A833 OD trans that has a B/E body tail shaft housing adapted to it?  I had one (A-body style) in my 77 Aspen RT back in the day and it seemed like to decent transmission.  Not sure if this came from a truck or car, any way to tell?  Price is right and the OD 4th gear is attractive.

GY3R/T

    Alluminum case counter shaft is full floating. Not as strong. IMHO 3.09 first gear ratio is too low. Good for the first 20 FT.  Has a unique set of gear ratios. 3rd gear is actually your OD.
      Not for me. :stop:

gzig5

Can you clarify the 3rd gear comment?  My understanding is that that 3rd is 1:1 and fourth is about 0.73.  So really, it is a three speed with an extra OD gear.  I have seen comments about the strength too, that's why I'm asking.  I'm going to be over 400-450 lb-ft on the engine by the time I get to swapping in the four speed and it will be higher than that if I go with a 4" crank on the 340.  Won't be drag racing much but mainly road course auto-x so the load profiles are different.


GY3R/T

    Third gear is .73 ratio. 4th gear is 1.00 ratio. (or one to one). 

RUNCHARGER

It really isn't going to be that great. As stated the gear ratios just don't work well, especially for a corner carver car. The case is aluminum and isn't bushed for strength. The 1-2 gear spread and 3-4 gear spread are way too far apart to work well. The OD gear is high enough that it would work with 4.10 rear gears however that would make 1st gear pretty much useless and you wouldn't even use it.
The engineers really messed the bed on this design. I think even if they had went a 2.66 low with the other ratios the same it could have worked. That way you could have run strong with 4.10 gears and you would have been able to shift it into OD on the highway. Conversely the early six cylinder trans with the straight through 4th gear and 3.09 low would work better. That way you could run 2.94 or 3.23 rear gears and be okay out of the hole with the 3.09 first.
Sheldon

GY3R/T

   Also think about your shift pattern. 3rd and 4th have been swapted.
    This is grandma's trans. :andyangel:

Chryco Psycho

I have done a number of these swaps , the A833 OD alum was used in trucks & vans it will hold up just fine , use it with a 3.23 gear & it will be fine , the rear pad may not be drilled for the shifter though but it is easy to drill & tap it


gzig5

Quote from: GY3R/T on October 18, 2018, 06:33:33 PM
    Third gear is .73 ratio. 4th gear is 1.00 ratio. (or one to one).

I'm sorry, that just doesn't make sense to me but I'm willing to be wrong.  That would mean when you shift from third to fourth your rpm increases?  Not the way the one I had worked.

gzig5

Quote from: Chryco Psycho on October 18, 2018, 06:58:03 PM
I have done a number of these swaps , the A833 OD alum was used in trucks & vans it will hold up just fine , use it with a 3.23 gear & it will be fine , the rear pad may not be drilled for the shifter though but it is easy to drill & tap it

I've got a 3.55 gear in the Cuda so I'm not that far off.  My 2000 BMW M5 has a 4.22 first gear and a 3.45 diff so I am use to first gear being used up early.  Gets that big car moving though. 
I thought these were used in trucks behind 318 and 360's so while not a Hemi unit, they shouldn't be exceedingly fragile.  Either way if I can get hold of it and it does eventually break, I won't have much into it.  From driving the BMW which has a rather fragile drive shaft setup, I've learned how to get the car going without dumping the clutch from 6000 rpm in first gear.

RUNCHARGER

Good luck with it. I truly think they are crap.
Sheldon

72bluNblu

Quote from: GY3R/T on October 18, 2018, 06:49:02 PM
   Also think about your shift pattern. 3rd and 4th have been swapted.
    This is grandma's trans. :andyangel:

On the mainshaft. The shift pattern is still the same as a standard 833, they flip the shift lever on the 3-4 rod to take care of the switch and everything topside works the same

Quote from: RUNCHARGER on October 18, 2018, 08:17:03 PM
Good luck with it. I truly think they are crap.

Well you truly don't know what you're talking about then

Quote from: gzig5 on October 18, 2018, 08:13:48 PM
Quote from: Chryco Psycho on October 18, 2018, 06:58:03 PM
I have done a number of these swaps , the A833 OD alum was used in trucks & vans it will hold up just fine , use it with a 3.23 gear & it will be fine , the rear pad may not be drilled for the shifter though but it is easy to drill & tap it

I've got a 3.55 gear in the Cuda so I'm not that far off.  My 2000 BMW M5 has a 4.22 first gear and a 3.45 diff so I am use to first gear being used up early.  Gets that big car moving though. 
I thought these were used in trucks behind 318 and 360's so while not a Hemi unit, they shouldn't be exceedingly fragile.  Either way if I can get hold of it and it does eventually break, I won't have much into it.  From driving the BMW which has a rather fragile drive shaft setup, I've learned how to get the car going without dumping the clutch from 6000 rpm in first gear.

The 833 OD's are sold short by all kinds of people that have never run one. You hear a lot of nonsense about how they won't hold up, how it's a weak design, etc. In stock form they aren't as strong an as a standard 833, that's true. But standard 833's are really strong transmissions, and the 833 OD's are still a lot stronger than plenty of other transmissions out there. No, they aren't the best transmission out there, the gear splits are pretty wide. But for an inexpensive way to add an overdrive gear they're hard to beat. Pretty much a bolt in operation, and you can run 3.73's and still have a great cruising rpm for the freeway at 70mph. Heck I have 3.55's in my Duster with a standard 833 that has a 3.09 first gear and 26" tall rear tires, and with the cam I run in my 340 I would still be better off with 3.73's or 3.91's on take off. Just depends on your set up.

Yes, the cases are aluminum. The bearing retainer diameter was also a whopping 5.125" to increase strength there and they all used the larger 308 input bearing. The shafts are supported in the case, so, it is important to check for wear if you're re-building one. But if the case isn't worn the transmission will last a long time. And, you can always bush the case for the shafts. If you're rebuilding one for more power, that would be a great addition. For a cruiser though it wouldn't matter as long as everything was in spec.

Here's a great article with information on the 833 OD's and some of the differences, it explains the gear configuration and the 3rd gear switch-a-roo http://slantsix.org/articles/4-speeds/ODA833fourspeed1.htm

And here's an older article from Mopar Muscle about bushing the shafts in the case on an aluminum 833OD. The article dramatically overstates the problem of case wear, I have 4 or 5 833 OD's and none of them exhibit "pounded out" cases like the article describes. Now I'm not saying their case wasn't a mess, I'm sure it has happened in transmissions that have been abused and maybe they really did get one that was trashed. But it is a magazine article and they want to play up their fix, so they talk up the problem too. There are plenty of 833OD's out there without problems anywhere near as severe as they claimed theirs had, they're not all junk.

Still, it is a good solution to increase the strength and lifespan of the case, and wouldn't be all that hard to do. Compared to the cost of doing a 5 or 6 speed transmission swap you'd still be WAY ahead, and no cutting on the car required.

https://www.hotrod.com/articles/mopp-0110-a-833-aluminum-case-buildup/

You can also switch the guts from an aluminum 833 OD transmission into a cast iron case. You'd need a 308 bearing main case, and you have to swap all of the 833OD parts in as a unit, no mixing and matching. But that would also remove the case wear from the equation.

Passon also makes their own gearset for the OD transmissions that has closer ratio's. Obviously more expensive than just using an old 833OD, but still less than a 5 or 6 speed conversion.


RUNCHARGER

Why would you spend money rebuilding one of these piles when for a few more dollars you could buy the Passon unit that has much better gear ratios and is inherently stronger? I doubt very much you are going to find a good OD833 these days, then if you do you are stuck with lousy (admit it) ratios and the huge bearing retainer?
You think I don't know what I"m talking about? I know that when you head down a rabbit hole you generally find worms and you'll be throwing good money after bad.
I have an OD in the garage right now. I bought it for the tailhousing and a few other parts. I won't use it even if it is perfect inside.
I've driven them plenty including my brothers new 76 Road Runner 318 and numerous miser pickups. They were never put in anything bigger than a 130HP 318. The factory didn't even think it was a good idea behind a smogger 360. I agree with you on one thing though, they were superior to most of the GM 4 speeds in strength.
I don't know how you would autocross with one. I guess you would have to gear it to use 2nd and 3rd only.
Like I say, good luck with it.
Sheldon

HP2

I thought the Passon unit had a multi-year backlog on delivery?

The 833OD doesn't sound like a great transmission, especially with the gear spreads, but it may be very compatible with the cruiser type driving many of our cars perform at this stage of their lives. I mean really, not all of us beat on cars at an autocross or drag race. A very large percentage of owners simply drive to show and shines, sometimes an hour or more away from home.  If you aren't leaning on  it hard nor regularly, why not give it a shot to improve the drive to the meet?

If you break it go back to your regular 833.

GY3R/T

   This is not the right trans to use in Auto-X driving.  If your converting to E-body application You would at least have to custom make the 3-4 shift rod, if not all rods. The lever indexing is also different than iron case 833. Invest your money in a strong (iron) case 833. especially if you're stroking the 340. Think about it. These trans were manufactured when horse power was non existant.

71vert340

I can speak from experience. My son and I installed an 833 OD trans from a 1976 Volare 318 car into his 71 Challenger with a mildly built 360. It ran fine. 1st gear was low so you had to shift out of it fairly quick. 2nd and 3rd gears were ok. The OD gear was great on the highway. My son was a teenager at the time and hammered the car and the tranny held up great. The car has a 3.23 rear end. We did end up switching it out to a standard 833. It got great gas mileage on the highway trips though. It just depends on what you want.
Terry