what is the best overdrive transmission for a Duster

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73 Plymouth Duster

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So I have a 73 Duster with a built 318 and a 8 ¾ 3.55 posi rear end. I cruise at 3000 at 60mph and the SOB gets 9.6mpg when I am really nice to it. haha so I need an overdrive. besides 5k for a Tremec what is the cheapest and best route to go without making new supports and totally reworking the mounts and car braces.

I know an 833 came in overdrive and 3 speed didn't it? I'd love a manual but what is the running price of a 833 overdrive.

Would a overdrive automatic bolt in easier? cheaper? or is there one that works for a Duster

-Thanks
 
73 Plymouth Duster said:
So I have a 73 Duster with a built 318 and a 8 ¾ 3.55 posi rear end. I cruise at 3000 at 60mph and the SOB gets 9.6mpg when I am really nice to it. haha so I need an overdrive. besides 5k for a Tremec what is the cheapest and best route to go without making new supports and totally reworking the mounts and car braces.

I know an 833 came in overdrive and 3 speed didn't it? I'd love a manual but what is the running price of a 833 overdrive.

Would a overdrive automatic bolt in easier? cheaper? or is there one that works for a Duster

-Thanks
Click to expand...

haha, sounds like me.

The OD 833 is the cheapest/easiest option, but not the strongest.
Then there is the GV overdrive that bolts to standard mopar auto/4spd(3k+rebuit trans)
Then you can see the auto overdrive systems. Both the 200r4/a500 will run you in the ballpark of 1500-2500 bucks
The Keisler 4l60e kit is 3k for the base level version.(requires notching/boxing the crossmember
 
Is your car a manual Or automatic? You didn't say.

The manual OD 833 can be picked up for a reasonable price used or rebuilt from brewers at a price.

The 904 was given a OD unit on the tail shaft and called the A-500.
It is leaner in weight and size next to the 727 OD unit called a A-518. It will fit a little easier. But it isn't a slam in and go thing.

You'll need to shorten the drive shaft
Depending on what you have now and install later, the trans yoke is a consideration. The manual and the 518 use the same home while the 500 uses a different one.

In any case, there is not to much improvement with a OD gear set if the engine is a built up one. The fuel consumption could largely be due to a large cam, carb and other items.
 
Sorry forgot to mention its a 727 automatic. I am mainly searching around on Craigslist, there are a lot of wrecked dodge trucks and such that say the transmission is good but I don't know if what they have would fit my car.

Like what did the 200r4/a500 normally go in? If I find a good deal on a wrecked car I could pull it myself.

Haha and ya rumblefish360 I knew when I built the engine I wasn't going for mpg but 12-13mpg would make it a little nicer to drive lol So what can I do with my 727? is the 518 a whole new transmission instal or can I add the overdrive unit to the tails haft of my existing transmission? I am prepared to shorten drive shafts and do a little modding, including cutting holes and installing pedals if I find a good manual overdrive.
 
The A-518 is the 727 with the added OD unit. Just get the trans out of any early Dodge truck. The trans mount will require some fabbing up. There is a thread here demonstrating it.
The 200R4 & the 4l60 is a Chevy/GM trans.
 
The A833 OD is not a 3 speed. I don't know why people insist on calling it that. Anything with the A833 designation is a 4 speed transmission. The 833 OD just happens to have 4th as an OD.

The best one for you car is relatively rare. It is the 1976 only transmission, which had a cast iron case. Find one of those, if you can.

To get an A500 or A518 in your car, you will have to do some major work to the floor and to the torsion bar cross member and the transmission cross member. If you want to stay automatic, the GM 200R4 is probably the best.
 
Do a search and look around. Welcome. Start with the sticky links at the top.
 
RustyRatRod said:
The A833 OD is not a 3 speed. I don't know why people insist on calling it that. Anything with the A833 designation is a 4 speed transmission. The 833 OD just happens to have 4th as an OD.

The best one for you car is relatively rare. It is the 1976 only transmission, which had a cast iron case. Find one of those, if you can.

To get an A500 or A518 in your car, you will have to do some major work to the floor and to the torsion bar cross member and the transmission cross member. If you want to stay automatic, the GM 200R4 is probably the best.
Click to expand...

So the 1976 one won't require cutting the crossmember or any serious modifications?
 
73 Plymouth Duster said:
So the 1976 one won't require cutting the crossmember or any serious modifications?
Click to expand...

It is a complete bolt in swap with all the right parts. If you have an automatic however, you will need a 4 speed floor hump. That does require cutting a portion of the transmission tunnel out and installing the 4 speed hump. Brewers sells fiberglass ones for 99 bucks and you can install them with screws and seam sealer. Other than that, it is a complete bolt in.
 
wow that's great to know! however I would still need to find pedals and such...
hypothetically what is involved with staying automatic with the Chevy 200R4? and what is it out of?

and another question why wouldn't any other 833 work for my car? I mean didn't 833 4 speeds come in Dusters? why wouldn't a 73 833 bolt right into my car. or were the 4 speed cars built a little different to accommodate the different transmission?
 
The adapter plate would be the biggest expenditure. I think they are in the 500 dollar neighborhood. Then of course there's the cross member mod and making the drive shaft work. Far as what they came out of....

The THM200-4R can be found in the following vehicles:

  • 1981-90 B-Bodies, Impala, Caprice, Delta 88, LeSabre, (83-86) Parisienne, and wagons
  • 1981-84 C-Bodies, Electra, 98, (82-84) DeVille & Fleetwood Broughams
  • 1984-88 G-Bodies and Pontiac Grand Prix, GMC Caballero, El Camino, Chevrolet Monte Carlo, Oldsmobile Cutlass Supreme, Regal
  • 1985-90 D-Bodies Cadillac Fleetwood Brougham & Brougham
  • 1981 Pontiac Firebird (with 301cid engine, non-turbo)
  • 1989 Pontiac Firebird Trans Am Indy Pace car (with Buick V6 and a Turbocharger)
 
RustyRatRod said:
The A833 OD is not a 3 speed. I don't know why people insist on calling it that. Anything with the A833 designation is a 4 speed transmission. The 833 OD just happens to have 4th as an OD.

The best one for you car is relatively rare. It is the 1976 only transmission, which had a cast iron case. Find one of those, if you can.

To get an A500 or A518 in your car, you will have to do some major work to the floor and to the torsion bar cross member and the transmission cross member. If you want to stay automatic, the GM 200R4 is probably the best.
Click to expand...

A minor amount of clarification. Technically, it's THIRD gear that's the OD. Both Ford and Mopar did a "trick" when they came out with the 4 speed OD boxes

Ma just flipped the 3-4 shift lever upside down, so when you move the SHIFTER 1-2-3-4 you are actually shifting the GEARBOX 1-2-4-3. Ma re-geared 3rd gear as an OD ration, and the "old" 4th gear now becomes your "new" 3rd gear.
 
Any MoPar 4spd trans will jus bolt in and work. How ever, the gear ratios are what need to be addressed. Also realize that the OD gear is the weak link. Also, the one cave eat to it NOT being a bolt in is the bearing retainer size. You can get an idea if you go to Brewers web site where they have many parts for sale. You'll notice various bell housings with various sized bearing retainer holes for the various transmissions bearing retainer sizes.
 
The installation of the GM trans is also done here at FABO. Search out the thread! It's around here some where. There are aome tricks to doing the swap.
 
I was trying to keep it simple.

67Dart273 said:
A minor amount of clarification. Technically, it's THIRD gear that's the OD. Both Ford and Mopar did a "trick" when they came out with the 4 speed OD boxes

Ma just flipped the 3-4 shift lever upside down, so when you move the SHIFTER 1-2-3-4 you are actually shifting the GEARBOX 1-2-4-3. Ma re-geared 3rd gear as an OD ration, and the "old" 4th gear now becomes your "new" 3rd gear.
Click to expand...
 
73 Plymouth Duster,

I'm doing the A-body 2004R swap right now,
http://www.forabodiesonly.com/mopar/showthread.php?t=252436
Lots of details but I'm not exactly sure on whether my '69 Cuda and the 73 Duster are exactly alike in the trans tunnel/cross member area. But I'm positive that there are experts here on FABO who can tell you any differences. Happy reading!!

treblig
 

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Man there is no easy solution. I like the gear vendors Idea if it were 1200 or less but 2800 is a bit steep for me. Found a 1999 dodge on CL and it has the overdrive transmission, the guy wants $650 for it but I also don't want to spend a week installing it. I think I am going to just keep my eyes peeled for a 76 833 with the overdrive and someday do that swap.
Thanks again guys
 
73 Plymouth Duster said:
Man there is no easy solution. I like the gear vendors Idea if it were 1200 or less but 2800 is a bit steep for me. Found a 1999 dodge on CL and it has the overdrive transmission, the guy wants $650 for it but I also don't want to spend a week installing it. I think I am going to just keep my eyes peeled for a 76 833 with the overdrive and someday do that swap.
Thanks again guys
Click to expand...

1999 trans is a 46RE...Electronically shifted...wont work.....

you need a 46RH...hydraullically shifter....last year in dodge trucks was around 1995ish...
 
Has anybody tried this 833 conversion kit? [ame]http://www.passonperformance.com/images/stories/passon_documents/Passon_Overdrive_Flyer_20091109.pdf[/ame]
 
magnumdust said:
My only problem is that a .80 overdrive is not a great ratio.
Click to expand...

It's not a perfect option but better than 1:1. I don't think the gear vendor is a lot better. The 200R4 is probably going to be the easiest since OP is running a automatic. I just thought this might work and no major tunnel mods. :D
 
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