3spd to 4spd OD trans

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Evilsizer

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i have been doing a lot of reading here and there. i think my 1976 Feather Duster has a A904 trans in it(3spd auto). im wanting a OD trans for when i pep up the engine so that i can still maintain a fairly high MPG. the Rear end is a 7-1/4, with what i believe are 2.76 or 2.73 rear-end gears.

im looking to find out if anyone know if and how much bigger/heaviers the A-500 trans is? if that is truely a truck trans only what would have been the sedan/coupe 4spd od trans? i have dont alot of looking on WIKI/ALLPAR, as i see 2 kinds of A5xx's and from the sounds of which both were used in trucks. if the A500 does work which one to look for the 40HR or the 42HR or was it 43HR.

thanks for the help!

*edit*
forgive me i should have looked more... i found some threads on what im after, no worries...

i guess anyone got pics of the 2 trans side by side and with the 5xx installed?
 
I guess it depends on what you are after, but for a mild cruiser you could leave those gears and get excellent mileage, know of a cuda that has a crate 360-300hp with 2.94 gears getting 17 mpg highway, but not a gear for quick ET's. :sleepy1:
 
I thought all Feather Dusters and Dart Lites were manual shift 3 spd OD cars for mileage? Yours is factory with an auto?
 
The A500 (42RH) or A518 (46RH) are derivatives of the 904 and 727 respectively. It's the OD section that is larger than the 904/727. With either tranny you will need to do some floor surgery to make room for the OD portion of the tranny.

FWIW, A buddy of mine has an A518 behind a hot 340 six-pak in his 67 Cuda with 4.10 gears in the rear end, he gets over 20mpg on the hiway. I get 21-22 mpg with a hot 360 and an A833OD with 3.55 gears on the hiway and 17-18 around town.
 
well its just a cruiser, gonna drive it to work off and on. That or just drive it on the weekends not sure yet.

@greg
from reading on allpar and another site seems the auto's where a rare option. just like the sunroof/moonroof in my duster. the manual's were OD's the 3spds no, it would have been nice to have a OD with different trans gears.

well i am thinking of switching the rearend gear to a 3.05 or 3.55 with a OD trans.

@superdart
i was reading that thread, i was hoping to not to have to touch the bodyto get the OD trans to fit.

@dgc
what about the 40HR, that showed up in the wiki page as a A500 trans.. i wonder if they are rare or something.

would i just be better off using the GV in the a904, then just change the gearing a bit.

thanks for the input guys!
 
One way to keep your rear gears but have the car have more pep off the line is either get a mid 80's or up 904 with the lower 1st gear set or just install a lower gear set in your tranny. This gear set would make your 2.73's feel like 3.04's.


Chuck
 
Evilsizer said:
well its just a cruiser, gonna drive it to work off and on. That or just drive it on the weekends not sure yet.

@dgc
what about the 40HR, that showed up in the wiki page as a A500 trans.. i wonder if they are rare or something.
Click to expand...

Never heard of a 40HR, maybe it was a version to go behind 4cyl's in Dakotas. When they switched to electronic control they made a 42RE and a 44RE both of these were 904 derivatives. The 44RE had more clutches in it.

There was also a 618 which was 727 derivative beefed up to go behind the diesel.
 
good idea chuck i may do that.. considering im wanting to keep the stock parts stock. imma have to find a used A904 then to "mod" for that wonder if the 80's 904 is different from the 76 in terms of size/weight. if i recall the 904 or its bellhousing in the duster is ALU. not for sure, i havent seen to much "detail" as to what it has. assuming my car is all stock i will have to get info on all the parts. i say assuming cause when i got the car some years back in highschool for $1400. the front hood is steel braced not ALU like i have been reading about.

you guys think i could then increase gas mileage more by installing a GV? as from when i recall driveing around 55-60 it sounded like the /6 was revving high, if i had to guess prolly in the 2.5-3k range.
 
I've read about 23 different posts about the OD tranny's. I'm still a little confused:?: ......... some of the questions I had were answered and some left me still wondering so I'm going to see if I can get a more specific answer if possilbe on some of my concerns.
First **
I've got a 904 trans behind my 340 tucked inside of a 73 Duster using a positraction unit with 3.55 gears......mostly to be used for crusing but an ocassional rubber burner:burnout:
I'm using this tranny with a 'B&M star shifter'. I'm wanting to put in an A500, since it seems to be (from my reading) a lot less of a problem than the A518.
Some say that you have to make the tranny tunnel a little larger to accomadate the switch over...........?? IS this true for a 73 Duster??

Second **
I currently have a 3000 stall converter in the 904 and when I change over to the A500, can this converter still be used or what will I have to do to utilize the stall factor of the A500 or is it not needed??

Thirdly **
I've received information about an A500 w/converter that has the 8 pin connector ........... said to have 23,000 miles. It 'supposed' to have come out of a 1999 1/2 ton dodge ram (2 wheel drive) that had a 318 engine (this unit being offered to me for sale ($250 + shipping)....good deal or not, I don't know.

Fourth **
I had found somewhere a wiring diagram for the A500 but NOW can't seem to find it.......any help on this will be very helpful.

Fifth **
I realize (from reading here) I'll have to shorten the driveshaft and modify the transmission Xmember..... other than that, I think that might be all that I'm really aware of.

I'd appreciate any help on this conversion........with the cost of gas & my current gas milage, I'd like to improve the milage so it won't hurt as bad when I go to fill up.

Thanks in advance...........:thumbup:
Greg
 
I can't answer all of your questions, but I can take a shot at a couple.
First, I don't think the converter will swap from the 904 to the A500. Seems like there is a difference in the pumps or the splines.....or something.
Second, it would probably be a deal IF its a good trans. Otherwise you've spent $200 for a core.
Third (or fifth) Actually, in order to get the trans in the proper position and not in a "tail down" attitude, you'll need to open up the trans tunnel some. You can just modify the crossmember and lower the trans enough to clear on top. But that's a pretty cheesie way to install it. It will cause the motor to "lean back" and will screw with your pinion angle
 
I've got some better pics I can post of mine to give people a better idea. I wish I had time to get over to Mikey's while he was doing the work, I really wanted to get detailed pics for everyone.

My trans actually came out of Randy's Green Sport....and as far as I know that car didn't have any tunnel work done to it either, but I could be wrong.
 
mtn_jake said:
I've read about 23 different posts about the OD tranny's. I'm still a little confused:?: ......... some of the questions I had were answered and some left me still wondering so I'm going to see if I can get a more specific answer if possilbe on some of my concerns.
First **
I've got a 904 trans behind my 340 tucked inside of a 73 Duster using a positraction unit with 3.55 gears......mostly to be used for crusing but an ocassional rubber burner:burnout:
I'm using this tranny with a 'B&M star shifter'. I'm wanting to put in an A500, since it seems to be (from my reading) a lot less of a problem than the A518.
Some say that you have to make the tranny tunnel a little larger to accomadate the switch over...........?? IS this true for a 73 Duster??
Click to expand...
Doesn't make any difference if it's an A500 or A518 the OD section of the tranny is much fatter than a 904 or 727 and will require tunnel surgery.


Second **
I currently have a 3000 stall converter in the 904 and when I change over to the A500, can this converter still be used or what will I have to do to utilize the stall factor of the A500 or is it not needed??
Click to expand...
No sure on that one but you will definately loose the lock-up feature of the A500.

Thirdly **
I've received information about an A500 w/converter that has the 8 pin connector ........... said to have 23,000 miles. It 'supposed' to have come out of a 1999 1/2 ton dodge ram (2 wheel drive) that had a 318 engine (this unit being offered to me for sale ($250 + shipping)....good deal or not, I don't know.
Click to expand...
A500's disappeared around 92 and it became a 42RH but the 99 would have a 42RE which is an electronically controlled tranny but if it's a v8 truck its more than likely a 46RE which is the elctonic version of a A518. You would need to figure away to hook up the engine control computer to make that tranny work.

Fourth **
I had found somewhere a wiring diagram for the A500 but NOW can't seem to find it.......any help on this will be very helpful.
Click to expand...
The A500 has a three pin connector, power, torque converter lockup and overdrive.

Fifth **
I realize (from reading here) I'll have to shorten the driveshaft and modify the transmission Xmember..... other than that, I think that might be all that I'm really aware of.
Click to expand...
Sounds about right.
 
Oh yeah..while I think of it:

- A 518 yoke will fit a 727, but a 727 yoke will NOT fit a 518. There is a depth issue.

- The yoke on the 45/545RFE fits the 518 perfectly. Good to see Dodge did not try to reinvent the wheel. This is the only automatice put behind the 5.7 and 4.7 V8s in 1500, Dakota and SUV applications since around 2002.
 
My FSM shows the A500 as being a lock-up trans only, so a non-lockup converter won't work with it. As for "surgery," read this post: 518 is in!!!
 
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