Swapping for an OD 904?

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ArizonaKid

ArizonaKid

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I couldn't find any threads in the search about this.

I was considering finding a later overdrive geared 904 for my slant equipped '74 dart swinger, since they can be found in the various slant trucks around. Are there any real benefits to this? Has anyone else done this, and if so, any real performance upgrades?

This was just a thought I had that could be done relatively cheaply and easily.
 
not sure if the 42RH came with a /6 bell housing.....
 
+1 Totally missed the slant 6. I think your're right. They started making OD trans in the 90's. I believe they stopped making the slant before then.

70aarcuda said:
not sure if the 42RH came with a /6 bell housing.....
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From Allpar:
"Mopar Action’s Rick Ehrenberg wrote that the basic TorqueFlite design continued long past the time when the transmissions were so labelled. In 1989 and 1991, integral overdrives were added, resulting in the A-500 (based on the A-904) and the A-518 (based on the A-727). According to Rick, the engine computer controlled the electric overdrive unit built into the extension housing."

You are probably thinking of the A904 lockup function. Which was implemented around 1977-78. Which basically reduced the cruising RPM by about 200-250. But IMO it made the trans slightly weaker.
 
Actually, I did mess up

In 1980, many rear drive Chrysler, Plymouth, and Dodge vehicles were given a wide-ratio version of the TorqueFlite, dropping down the first gear from 2.45:1 to 2.74:1. Second was moved from 1.45 to 1.54; third remained at 1.:1, reverse at 2.22:1. All Torqueflites adopted this gearset in 1981.

I was thinking of the wide band ratio.
 
ArizonaKid said:
Actually, I did mess up

In 1980, many rear drive Chrysler, Plymouth, and Dodge vehicles were given a wide-ratio version of the TorqueFlite, dropping down the first gear from 2.45:1 to 2.74:1. Second was moved from 1.45 to 1.54; third remained at 1.:1, reverse at 2.22:1. All Torqueflites adopted this gearset in 1981.

I was thinking of the wide band ratio.
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All good. Go for it! I found an A999 which is basically a beefed up 904 with wide ratio gears. Never looked back, I did a non-lockup conversion a few months ago.

If that's the case it's a bolt-on deal, if you go with a lockup one, you will need to get a specific torque converter and they're not very cheap.
 
Tantibus-74 said:
All good. Go for it! I found an A999 which is basically a beefed up 904 with wide ratio gears. Never looked back, I did a non-lockup conversion a few months ago.

If that's the case it's a bolt-on deal, if you go with a lockup one, you will need to get a specific torque converter and they're not very cheap.
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So the wide band is better, how exactly? This was just one of those thoughts I was considering doing.
 
Better off the line and low speed acceleration. Especially if you have numerically lower gear ratios like 2.96, 2.71 etc.
 
If you decide to go to the A500/518, start looking for the really hard-to-find slant to transmission adapter. Yes, such an animal exists as I have one I would like to use in my 87 slant-equipped truck.
 
So to come back to this, does anyone know a way to tell the difference between a regular 904 and a wide band 904? I decided this would be good for my V8 upgrade.
 
ArizonaKid said:
So to come back to this, does anyone know a way to tell the difference between a regular 904 and a wide band 904? I decided this would be good for my V8 upgrade.
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Not a whole lot. As I recall the wider band was used behind the 318, and that's about all. Friction plates, steel plates, gasket set, etc. all the same in the 904. The drum might be a bit wider, but I don't have that information at hand.
 
Physically, the outside appearance is the same, so it'll be almost impossible to tell just by that. You can easily tell if its lock up or not.

But to discern if its an A998 or A999 or even a A904T (904T's are wide ratio but will be weaker than the 998/999's)
You will have to pull apart the Trans and look at the sun gears.
The serial numbers on the side where the transmission pan mount can get you in the ball park. Then there is the 10,000 day calendar coding you can try and decode.
If it was made around 1980's, there is a fairly good chance it'll be a wide ratio setup.

Been through this myself a little while ago:

http://www.forabodiesonly.com/mopar/showthread.php?t=218722

Hope this helps
 
Chrysler made trucks with slants and overdrive transmissions. The A833 OD. Although the truck transmission can be made to work in an A body, it's a bit of work. The shifter needs to be moved by using a custom bracket or the tail shaft has to be swapped on from an A body transmission.

So, to clarify, there WAS an overdrive transmission that came behind a slant six.
 
RustyRatRod said:
Chrysler made trucks with slants and overdrive transmissions. The A833 OD. Although the truck transmission can be made to work in an A body, it's a bit of work. The shifter needs to be moved by using a custom bracket or the tail shaft has to be swapped on from an A body transmission.

So, to clarify, there WAS an overdrive transmission that came behind a slant six.
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OK. now we're talking manuals ok, yes so technically S6 did have OD option. (always with the technicalities, sheesh)
 
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