Automatic Overdrive Transmission (AOD) swap
In the first half of 2019, the owner of
Roadster # 897, Ron, upgraded his C4 transmission (that was
original to the car) for a overdrive transmission. Here are his
notes and pictures.
An important thought from Ron, the contributor of this info.
don't want to mislead that it was a simple task.
As of May, 2019, Ron can be reached at Ronmoore007@yahoo.com
Roadster 897 from Westport Indiana. Over the winter of 2018-2019 I
swapped out my factory C-4 to a AOD and wanted to share the results and
how it is running.
I ordered it from Monster Transmission and it took them 5 weeks to build it for a cost of $2,000.
The AOD is much larger so it needed some help to make it fit. See my picture of the two.
Fitting the new transmission
I needed to drill out most of the pop rivets on the transmission tunnel
so I could get the bolts started. I left in a few of the rivets and it
hinged on the front. Ron might also have
removed ALL the rivets and merely lifted the part out of the car. By
leaving it connected, he saved time aligning the part to re-close the
hump. When it was done I just went the next size up rivet
and fastened it back in. Left side of the
picture below is the 1800 rpm stall converter and on the right is the flexplate
The old c-4 had plenty of room but the new AOD is tight. The new one mounting bolts are 2 1/4" long. To raise the new one high enough so the pilot in the converter and crankshaft can mate and slide it needed more room. Once it is slid back on the crankshaft and the four converter to flexplate bolts are aligned (converter has a drain plug that needs to be in one of the two flexplate clearance holes) the issue goes away. The old c-4 tapers off quick but the AOD has a larger housing. I chose to put the mounting bolts in before mating the trans to the motor. I did not want to figure out how to put the top two bolts afterwards.
I purchased two Spicer 5-153X U-Joint Kits https://www.amazon.com/dp/B000CKN762/ref=cm_sw_r_cp_apap_JJDyBmf5ffld3
(My 45 year old sealed U-joints had rust and soon would fail. These new ones have a zurk grease fitting).
I cut one inch off the yoke of the old c-4 and this compensated for the
AOD being one inch longer. Just a hacksaw and de-burring.
I needed to make a new transmission mount for the old C-4 would not
work. I took some 2 inch angle iron and made two small pieces to
bolt to the stock channel iron welded to the frame. I used socket head
cap screws with blue die springs to mount the angle to the transmission.
See the attached pictures. Another option
would have been to cut off the old mount and re-weld it further back on
the frame. This solution is easier, and likely stronger than
moving and welding old steel. There may be a universal
transmission crossbar available, but attaching it to the frame presents
the same issues.
I needed to run the TV cable to my Edelbrock Carb. (I said goodbye to my Holley long ago for blowing power valves). I chose to order a new Lokar TC-1000U 24" Universal. throttle cable .. https://www.amazon.com/dp/B000COMNO0?ref=ppx_pop_mob_ap_share
My car already had a Hurst ratchet shifter so I continued to use it.
Wired to neutral safety and the others to reverse backup lights.
I will show you my disc brake conversion. I used S-10 disc brake cylinders and Jeep rotors. I used a Ford Granada power brakes master cylinder and tilt steering wheel from that junkyard car. I used the complete wiring harness from that car so I have a good wiring diagram. This put the dimmer switch on the turn signal arm.