Lower cost transmission options?

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MopaR&D

MopaR&D

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I'm currently going through swapping the drivetrain in my '70 Duster from 318/904/7.25 to 360/904/8.25. I was planning on having the original A-904 rebuilt with lots of goodies by A-R-T Automotive in Franktown, CO but have now come to the conclusion that it's out of my budget. It was going to get an A&A reverse-manual VB, A-999 low gear set, deep cast aluminum pan, PTC converter, heavy-duty everything else... Basically the works. I know this would be the "right" way to get a good performance trans behind my 360 but I just can't afford it, unless I wait three months to save up the cash (and that's aside from all the other stuff I still have to buy for my car). What should I do? Find a used one in good shape and pull it apart myself? I've never played around with transmissions so it would be my first experience. One important point, I do plan to convert to a manual tranny (4- or 5-speed) in the near future (few years?) so the trans I run now doesn't have to be totally bulletproof. But I would still like to have peace-of-mind that it won't blow on me a few months down the road.
 
MOPEkidD-3 said:
I'm currently going through swapping the drivetrain in my '70 Duster from 318/904/7.25 to 360/904/8.25. I was planning on having the original A-904 rebuilt with lots of goodies by A-R-T Automotive in Franktown, CO but have now come to the conclusion that it's out of my budget. It was going to get an A&A reverse-manual VB,

Why? You gonna drive it on the street? At any rate, if you REALLY want a manual unit, get the Mopar Performance chassis manual. It tells you how to modify YOUR auto valve body to make it manual yourself. Nuthin to it.


A-999 low gear set,

The 999 gearsets were introduced to get the heavy, high rear geared cars of the late 70s and early 80s going off the line better. No need for them in a light A body with a decent gear. Waste of money.

deep cast aluminum pan,

Get the steel one with the tubes runnin through the bottom. They're called cooler pans. MUCH better than cast aluminum any day. cheap on Ebay.



PTC converter, heavy-duty everything else... Basically the works. I know this would be the "right" way to get a good performance trans behind my 360 but I just can't afford it, unless I wait three months to save up the cash (and that's aside from all the other stuff I still have to buy for my car). What should I do? Find a used one in good shape and pull it apart myself? I've never played around with transmissions so it would be my first experience. One important point, I do plan to convert to a manual tranny (4- or 5-speed) in the near future (few years?) so the trans I run now doesn't have to be totally bulletproof. But I would still like to have peace-of-mind that it won't blow on me a few months down the road.
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Several things left out for the rest. what rear gear? All you really need is a good quality shift kit, you can get a higher ratio kickdown lever, and I recommend a five disk direct drum and a four disc forward drum. They can be found here very reasonably: https://www.wittrans.com/Schematic.aspx?Transmission=A904
 
Well I wanted to use 2.94, 3.07 (Jeep), or 3.23 gears depending on what I can find for the best price. I'm building the car more for road-racing and high-speed handling than drag racing. I also want to be able to cruise on the highway to faraway places and get good gas mileage and have my engine last a long time. I figured with those higher rear gears the low-gear set for the transmission would help to make up lost acceleration especially off the line.

Looking at the link you posted I would need to get PN 12555A? It says it's for 1971-89, would it still work in my 1970 tranny? And then the forward drum would be PN 12554C? I'm looking at getting the rebuild kit, valve body, and converter from Cope Racing Transmission, is this the kit I should go with?

https://www.coperacingtrans.com/product_info.php?cPath=56&products_id=427
 
Your best bet is to PM 346Duster(Chris Andrews Racing transmissions)and get some advise from him on your tranny build.I,ve found him to be very helpful and just an all around nice guy.
 
MOPEkidD-3 said:
I'm currently going through swapping the drivetrain in my '70 Duster from 318/904/7.25 to 360/904/8.25. I was planning on having the original A-904 rebuilt with lots of goodies by A-R-T Automotive in Franktown, CO but have now come to the conclusion that it's out of my budget. It was going to get an A&A reverse-manual VB, A-999 low gear set, deep cast aluminum pan, PTC converter, heavy-duty everything else... Basically the works. I know this would be the "right" way to get a good performance trans behind my 360 but I just can't afford it, unless I wait three months to save up the cash (and that's aside from all the other stuff I still have to buy for my car). What should I do? Find a used one in good shape and pull it apart myself? I've never played around with transmissions so it would be my first experience. One important point, I do plan to convert to a manual tranny (4- or 5-speed) in the near future (few years?) so the trans I run now doesn't have to be totally bulletproof. But I would still like to have peace-of-mind that it won't blow on me a few months down the road.
Click to expand...
I agree with strokerscamp, "Why? You gonna drive it on the street? At any rate, if you REALLY want a manual unit, get the Mopar Performance chassis manual"
I dont think you need too much, heres what i did although I have a 727, but you can do the same with the 904, I bought the Performance rebuild kit from Mancini, AND the bolt in sprag, then had a local tranny shop rebuild it total cost was $600.00 and it works AWESUME, not sure how powerfull of a 360 your building.... I left mine standard pattern as I also have a factory slap stick from a chally and it has NEVER missed a shift. I drive mine mostly on the street so manually shifting all the time would suck, also someone correct me if i am wrong but you need to leave the kickdown linkage hooked up unless you are going FULL manual. I bought the Lokar kickdown, it looks and works better then the factory unit.
 
pettybludart said:
Your best bet is to PM 346Duster(Chris Andrews Racing transmissions)and get some advise from him on your tranny build.I,ve found him to be very helpful and just an all around nice guy.
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That's just the guy who was going to build it for me! His shop is about 30 minutes north of where I live and I have talked to him in person about it. All of the parts I listed in my first post were recommended by him and were laid out in a quote he wrote up for me. He recommended against a forward shift pattern and for a reverse-manual VB with low-band apply. I'm not concerned about shifting on the street because I wanted to convert it to a 4-speed anyway (plus my DD is stick-shift too). Really my main concern with a reverse shift pattern is the inability to shift into neutral for coasting but I have a feeling that's a bad idea in itself.

And before I forget again my 360 is going to be stock-stroke with mildly worked Magnum heads (normal replacement ones), around 10.5:1 comp, Lunati Voodoo 256/262 cam (with 1.6:1 Magnum rockers), RPM AirGap intake, and Doug's headers.
 
Then go talk to Chris. I'm sure he'll help. Look man, I'll tell you straight up. if you can screw a bolt in with a ratchet and socket, you can build a 904. That's no exaggeration. They are that simple. How you like those prices on that link I posted for you? LOL Ain't they a hoot? Other folks want like 399 bucks for a 5 disc direct drum...EMPTY and those come with NEW clutches and steels INSTALLED for less than 60 bucks.. Can't beat it.
 
StrokerScamp said:
Then go talk to Chris. I'm sure he'll help. Look man, I'll tell you straight up. if you can screw a bolt in with a ratchet and socket, you can build a 904. That's no exaggeration. They are that simple. How you like those prices on that link I posted for you? LOL Ain't they a hoot? Other folks want like 399 bucks for a 5 disc direct drum...EMPTY and those come with NEW clutches and steels INSTALLED for less than 60 bucks.. Can't beat it.
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That's all I needed to hear. I have no problem tearing apart anything else on my car and I was a bit intimidated at first just from looking at exploded views of auto trannies. That is awesome about those prices too, how can there be such a huge difference between WIT and the others?

Anyway sounds like a good plan so far, what about the overhaul kits offered by WIT? Altogether will I need one of those, the two drums, and the valve body? Here's another question, what's the difference between a shift kit and a valve body?

EDIT: I found those pans with the cooling tubes (made by Derale) but they are only available for the 727/518...
 
MOPEkidD-3 said:
That's all I needed to hear. I have no problem tearing apart anything else on my car and I was a bit intimidated at first just from looking at exploded views of auto trannies. That is awesome about those prices too, how can there be such a huge difference between WIT and the others?

WIT sells remanufactured parts. the clutches and steels are new, but the drums are reworked. Polished back up and new bushings installed. Still a screamin deal.

Anyway sounds like a good plan so far, what about the overhaul kits offered by WIT? Altogether will I need one of those, the two drums, and the valve body? Here's another question, what's the difference between a shift kit and a valve body?

The shift kit is just a kit that basically reprograms the valve body for different shifting characteristics. the valve body itself it the actual brain of the transmission telling it under what conditions to shift and how to shift. It, along with the governor assembly and throttle pressure linkage, tells the transmission when to shift.

EDIT: I found those pans with the cooling tubes (made by Derale) but they are only available for the 727/518...
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Lastly, I've been recommending Transgo transmission shift kits for years....but have recently changed my ways. through talking with some really high end transmission shops, I think B&M is actually a better way to go, but you should get their "transpack". It is a much more indepth reprogramming kit, not just a shift kit.
 
Looked up the B&M Transpak and I think I'll go with that. Now what's the higher ratio kickdown lever you mentioned? Does it make it downshift with less throttle opening, or is it just for durability purposes?

EDIT: And one more thing, what about a shifter? I was going to get a Turbo Action Cheetah SCS one but if there are other decent ones out there for cheaper I'll go that route.
 
Unless your building a super strong/high hp 360 a manual valve body with a decent converter and cooler should be plenty. Stroker scamp is correct the lower first in the 904 would be mostly advantageous in a heavier car.
 
Well if I can find an old A-999 for the right price I figure I might as well. FYI Chris Andrews also recommended the lower gear set, saying it helped compensate for the high (3.23?) gears in his own road-racing '73 Duster 340 he put together for the Leadfoot Rally in Pueblo last year. I know he has a few pics of it on FABO, I just have to do a little searching...
 
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