Ok. I've got a 1934 Ford 1/2 ton pickup with Ford 302 and C-4 trans. To install the trans I removed the rivets of the (I'll call it the saddle) X member and made my own supports for the C-4. No cutting of the actual X member! My question is will a AOD fit in the frame without major mods to the X member? Am running 3.70 gears and a little too much RPM's at highway speeds. If too much modification is needed, then I'll go to 3.23 ratio and keep the C-4!! Can't find any threads pertaining to this. Thanks!!
AOD is basically a C6 with OD . Lots larger than a little brother C4 . So you may need floor mods , only way to determine is start and work to the finish line . You will The the AOD , just be sure to correctly attach and adjust the TP (Throttle Pressure ) cable or you get a chance to see what it takes replace the trans again sooner than you hope to .
It will require far more modifications than you expect. The AOD is considerably larger in every way. I'd go T5 before AOD.
Taller tires are the Cheapest way to fix your R.P.M. issue if you have room. As mentioned, the A.O.D. is a monster setting next to a C-4. Not only that they eat more H.P. to make things work. Not always a good change up. That said I run an A.O.D. in my Vicky and wouldn't change a thing it that specific car. To me it's all about where you find the Fun Zone when you're driving. The Vicky is a road car. I would never put an overdrive automatic in my Coupe. Total different driving factors.
I contend that you won't know until you try it. The AOD gets a bad rap at times because of past factory throttle bracket failures I believe. And the fact that you must pay close attention to cooling and pressure adjustment points. I've been running one for years in my 55 bird bolted up to around 350 hp. When I did it I couldn't find anyone else that could give me any solid comparable advice. I forged ahead and learned a lot. I am very happy with the way my install worked out and that I had to figure it all out on my own by trial and error. That's how a hotrodder would do it.
I might also say, to me there was no benefit to staying with a C4 with all the work to get there, you might as well go to an AOD with more potential benefits in the long run. I got a lot of incorrect info about how to do it and what the AOD was capable of. For example, a few had done a swap and were fine with it BUT, were not able to downshift when descending a long grade! What!, why even bother to build something that way? Build it for its intended purpose and use it to enjoy.
I agree with y'sguy, if you're going to do a little t******* to get a C-4 in it just do a little more and go with the AOD. Us old guys call then the New trans, but they are already 20+ years old. In the beginning the Throttle pressure control was a headache but Trans shops have been there done that today and getting things correct aren't as big a problem as they used to be. It is very critical though that you get it right.
I put an aod in our 40 coupe years ago with a 302/5.0. The x-member had to be trimmed on the top of the center piece, and the front V part of the x notched a bit, not as much as you’d think. Flat plate was welded to box it all in. The floor needed a big hump!! This was all done with the body on the frame. After sloshing around with a slippery aod for a year or so, I finally found the right t-5 with the forward s-10 shifter, and it is basically awesome. The fit is perfect and it is way more fun to drive. I made a bell crank for the clutch, and the driveshaft was within 1/2”. The floor gained much needed space too. The aod definitely absorbs the horsepower! TP
memory says the c4 was about 11" wide... the aod was about 14"... i think i had to trim the lower "flange" of the x member,,,
Thanks for all the input!! Considering that a good rebuild of a AOD will run at least 2 grand not to include different flex plate, shortened drive shaft, etc. I'll stick with the C-4 and a 3.23 ratio rear gear to reduce RPM's. The truck is completed and too much work to remove the entire drive train to get at the trans. The C- 4 works great other than the mentioned RPM'S And the price to get new gears and have them installed is $450 if I pull the center section myself!! Old School Rules!!!
I think you're making a pretty good choice. Given the Curb weight of your Truck pending the current tire size I may step up to 3.0's. You are aware that there is a Math formula that will give you the exact motor R.P.M. at a given M.P.H. using the current tire size and chosen gear ratio, right? You don't have to guess at what you'll end up with at 70 M.P.H.
I've been running a 351W/C4/3.00 gear in my 47 coupe for 30 years. Manages all highway speeds, sure won't be a quick as your current setup, but you'll probably like it in the long run. I decided to install a 700R4 behind the 351W last year as I had one, and thought the overdrive would be good for today's higher speed limits. Had to open up the x-member and relieve the floorpan hump for its size. The AOD may be smaller than the 700, but I still think it's much bigger than the C4.
A 200R OD GM trans is one of the smallest if you can get an adapter. There is so much information on them it’s easier to get then correct on the cables..
Early AOD is tuff , but you have to get the throttle pressure correct . There is plenty of info on fixin it up perfectly today . It’s not as it was when it was a newer trans . There have been tons of them cooked because the cooler was not large enough also . If you choose do your home work and do it right the first and only time .
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