A500/A518 questions

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rustytoolss

rustytoolss

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Does it matter what year overdrive you buy for a swap. As far as the electrical needs to make them work ? Are there better year transmissions to look for ? That will make life easier.
 
the RE version is controlled by a computer....you dont want that one...you want the RH version...hydraulic control governor...had 3 pin plug on it...

What you are looking for is a 46RH which is based on the 727 or the 42RH which is based on the 904.

The RE version started showing up around 1996.
 
70aarcuda said:
the RE version is controlled by a computer....you dont want that one...you want the RH version...hydraulic control governor...had 3 pin plug on it...

What you are looking for is a 46RH which is based on the 727 or the 42RH which is based on the 904.
Thanks.
The RE version started showing up around 1996.
Click to expand...
Thanks.
 
70aarcuda said:
the RE version is controlled by a computer....you dont want that one...you want the RH version...hydraulic control governor...had 3 pin plug on it...

What you are looking for is a 46RH which is based on the 727 or the 42RH which is based on the 904.
Do you know if the a500's from a V6 , are as strong as if they came from a V8 ?
The RE version started showing up around 1996.
Click to expand...
 
rustytoolss said:
Are the a500's from a V6, as strong as the a500's from a V8 ?
Click to expand...

Everything I have seen shows the V6 and V8 42RH are the same transmissions.
Pre 1996 (1995 and back) are 42RH and after that they were computer controlled (42RE)
The RE can be used, but require an aftermarket computer controller if used in a vehicle that does not have the OE computer.
 
Got a bunch of questions about the A500 - 42RH. Trying to round up parts for my sons barracuda. Car will have a mildly warmed over 318. Using a 3.73 geared explorer rear. Dont want to use an A904 by itself. Car will wind too high on the freeway just trying to keep up with traffic. A gear vendors on an A904 is to cost prohibitive though it would be easier to mount up with a stock console floor shifter since it attaches at the back of the trans. The .69 overdrive of the A500 42RH seems ideal. And will allow the engine to run at a lower happier RPM at 70mph. Big block dart website shows with a 25.5" diameter tire and 3.73 gears a 3 speed would put me at 3500 @ 70 MPH. The A518 which i am assuming is a 727 based 4 speed with same ratios puts me at 2400 @ 70 MPH with the same gearing and tire size. Now heres all the questions.

What type of vehicle and what year to what year range can i find an A500 in?

Ditto for a 42RH

Would prefer A500 over a 42RH but whats the advantage to having electronic lockup on the 42RH compared to hydraulic lockup on the A500. Trying to stay away from wires if i can.

Have a 3 speed floor shift in a console. Can the linkage be modded to work to keep the stock shifter. Is there a kit for this?

Is the indicator like that of a 3 speed, 1,2,D and overdrive just locks up and unlocks on its own via line pressure and RPM, or a switch in the case of the 42RH, or is there a 4th detent on the shifter.

Are there any trans tunnel mods, and crossmember mount mods?

Will an A904 yoke and U joint work for this, or are the splines different and requires the yoke from the donor.

If you have to use the yoke from the donor vehicle is there a bastard u joint available to attach donor yoke to stock A body driveshaft.

What kind of kickdown setup does it use?

Is there an aftermarket cable type kickdown push pull setup available for it?

Sorry for all the questions I'm just trying to make an educated decision
Thanks
Matt
 
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Someone correct me if I'm wrong, but I think the 500 and the 518 use the same overdrive; same yoke like a 727. Not all ods are lockups. Crossmember is definitely different. Same type of kickdown arm.
 
42RH was hydraulic and exactly the same as A500. 42RE had electronic shift control (torque converter was the same and locked hydraulically). All used the same overdrive, but the later units were better than the first couple years. Basic difference was 2WD or 4WD. The OD unit from a Cummins 3/4 ton truck will bolt to a 42RH.
 
Anybody have some drivers side pix of a 42RH they can share? I am wanting to look at it and see if i can adapt my stock factory 3 speed floor shift linkage to it.
 
moparmat2000 said:
Anybody have some drivers side pix of a 42RH they can share? I am wanting to look at it and see if i can adapt my stock factory 3 speed floor shift linkage to it.
Click to expand...

I have the 42RH behind a 5.9 and I can tell you for sure that your stock linkage (or aftermarket for a 904) will work just like it does on the 904.
Even though the 42RH is a hydraulic unit, the OD and converter lockup are both electrically controlled.

I used adjustable pressure switches connected to the governor port on the trans to tell OD and lockup when to happen by road speed.
My normal floor shifter has the 12DNRP and these two switches determine how and when (or if) OD and lockup come in.
I have the adjustable pressure switches set where OD come in at 55 and lockup at 75 automatically, or either/or can be turned off completely.
With both of these switches in the Off position the trans is exactly a 904 with a low first gear.
With both on, it shifts 1, 2, 3, OD, lockup completely automatically.
With the "4th" in the off position it shifts 123 and lockup at 75mph.
With lockup (5th) in the Off position it will shift 123OD.

This is the exact same shifter I had on my 904 before I changed to the 42RH, but with the switches for OD and lockup added to it.

ShifterArt.jpg
 
Trail beast thank you for answering some of my questions, however i have some more questions to narrow the selection down a bit for me. I saw that uscartool makes a nice 42RH trans crossmember. I am a welder and fabricator so i can make this part no problem. However heres a few more Qs

Does this transmission have a cable hook up for a speedometer? If so what years has this, and what years did they do away with it?

You mentioned the shifter lever hooks up the same, but are using a cable operated shifter. I plan on using a stock A body console floor shifter. Is everything in about the same location on the trans as an A904?

What kickdown linkage was used? Stock A904? Or something else? I ask this because i can get a cable operated setup from summit for this purpose.

Yoke? Will an A904 yoke work? Or do i need one with donor trans?

If a yoke from the donor vehicle, what u joint works to adapt that to an A body driveshaft?

Thanks
Matt
 
Most of them have cable speedometer, but some (later) ones could be electronic, BUT, it's just a bolt on item and can be changed to cable easily.

42RH/A500 = 904 'body' + OD
46RH/A518 = 727 'body' + OD
Both OD transmission types have the same smallblock bellhousing. Large spline yokes.
KD-linkage is exchangable, but the lever could vary per use or transmission. A cable would make things easier.

An A-body driveshaft needs to be shortened a few inches.

I 'control' the OD on my A518 with a simple toggle switch on the console.
Use a 3-step switch for OFF / OD / OD+Lockup.
 
Large spline yoke like a 727 type?

Is it the same u joint as an A body driveshaft though?

UScartool has a bolt in A500 crossmember. Do you still have to mod the trans tunnel?

See pic below of uscartool crossmember. I can make a similar copy of that.

Screenshot_20180918-112720.png
 
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Yes the upper part of the crossmember needs to go or else the transmission will be angled downwards too much (unless you like a gasser or 4x4 stance), and the driveshaft-angle will be more.
Cut the floor and weld a thick curved plate from inside the cabine at the same location to maintain crossmember integrity.
If you don't, the spot welds where the crossmember is welded to the floor besides the tunnel will tear apart. Got the T-shirt.

Anyone with an angle grinder and a welder can modify the stock crossmember in half an hour's work.
Use a mid '80s GM transmission mount. It's a good fit.
 
I am concidering 1/8" rolled strapping to tie the 2 sides of the crossmember together but doing that from underneath.

With a 67-76 A body is the torsion bar crossmember wide enough that all the existing trans mount bolt holes can be used?

What length speedometer cable do you run? I have an 80" length cable.
 
Nope, they all require the same cutting. Some of the weakening of the crossmember can be offset with subframe connectors and torsion boxes. But you want to do that anyhow.
 
C130 Chief said:
Nope, they all require the same cutting. Some of the weakening of the crossmember can be offset with subframe connectors and torsion boxes. But you want to do that anyhow.
Click to expand...

Thank you C130 Chief,

Car i am wanting to do this to 69 barracuda has 2x2 thin gage steel subframe connectors on it prev done back in the 80s. I will be changing them out for heavier gage 2x3 box same as what i did on my 67. I also have templates from torqueboxes i made for my 67 out of 1/8' plate steel. Will be making up a set of these for the 69 as well. So that is all in the works.

Was thinking i can cut out the U part of the crossmember and just weld in 1/8" flat strap bent to a U shape from underneath to tie it back together. I am sure theres enough clearance there.

Since its a future project with my son, i am trying to round up everything needed for it now while its still plentiful in the wrecking yards. Woild like to grab an A500 or 42RH as its also called. I am assuming a 91-92 ram van or pickup will have one with a speedometer cable. From pix i have seen of these it looks like the neutral safety / reverse light switch uses the same switch and wiring as a 69 A904.

Will the A body kickdown linkage work? Would be nice to use it if i could. Looks like theres a boss on the side of the A518 bellhousing for the kickdown lever crank.

This is all coming together nicely in my head. Now i gotta find a transmission.

Anybody have a wiring schematic on how to wire up the lockup solenoid? I was going to use a mopar lockup pushbutton from a van or a pickup to actuate it.
 
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