The Ford Barn

jmerson · 11-17-2016, 08:40 PM

I want to change my '34 sedans FMX transmission to an AOD. Is the AOD larger in diameter than the FMX?

Jim

Ardun · 11-17-2016, 10:01 PM

On the AOD, pay close attention to the rear end gear ratio. With a 3:70 or lower, the 1-2-3 shift occurrs way too soon and downshift not soon enough causing engine bog. I used a Transgo Hi Rev shift kit to correct the problem as best as possible. Do some research or you may be disappointed. A higher ratio would eliminate this also.

I have an FMX in my 34 and like it. Have an AOD in my 53 with a 3:90 rear end and am happy since I put the kit in. I don't recall the size difference.

Tom

rotorwrench · 11-18-2016, 12:17 PM

Sponsored Links (Register now to hide all advertisements)

The FMX was the very pinnacle of the evolution on the Borg Warner designs beginning with the first Ford/Merc-O-Matics in 1950. The AOD surpasses it by a good bit but you do have to find out which one will work the best for your application and how to make all the features work correctly. Some of them are larger.

11-17-2016, 08:40 PM	#1
jmerson Member Join Date: Mar 2012 Location: Waterloo,CA Posts: 50	AOD vs FMX I want to change my '34 sedans FMX transmission to an AOD. Is the AOD larger in diameter than the FMX? Jim

11-17-2016, 10:01 PM	#2
Ardun Senior Member Join Date: Jun 2013 Location: Reno Posts: 171	Re: AOD vs FMX On the AOD, pay close attention to the rear end gear ratio. With a 3:70 or lower, the 1-2-3 shift occurrs way too soon and downshift not soon enough causing engine bog. I used a Transgo Hi Rev shift kit to correct the problem as best as possible. Do some research or you may be disappointed. A higher ratio would eliminate this also. I have an FMX in my 34 and like it. Have an AOD in my 53 with a 3:90 rear end and am happy since I put the kit in. I don't recall the size difference. Tom Last edited by Ardun; 11-18-2016 at 09:46 AM.

11-18-2016, 12:17 PM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,426	Re: AOD vs FMX Sponsored Links (Register now to hide all advertisements) The FMX was the very pinnacle of the evolution on the Borg Warner designs beginning with the first Ford/Merc-O-Matics in 1950. The AOD surpasses it by a good bit but you do have to find out which one will work the best for your application and how to make all the features work correctly. Some of them are larger.