No reverse 904 trans

[mopar74]

1973 Dart slant six 904 auto. I came home from work tonight and went to back the car in to my driveway, put car in park to open the gate and when I put the car in reverse there was a loud clunk and and no reverse. All other gears seem to be working fine as I had to drive the car around the block to line up for a straight shot to park in front of my house. I did not lift the hood as it is dark and raining tonight. Any idea as to what might have happened? valve body issue or pull trans? I have another trans but do not know the condition and I think it will get rebuilt before I install it if I need to. the trans has been working fine up untill tonight. Looks like I'll be pulling the 74 Challenger out of the garage to drive in this rainy weather.
Thanks in advance for any advice as to what it might be,
Kevin

 

[70aarcuda]

probably blew the rear servo in the trans...going to have to drop the pan and check to see if it is cocked in the bore...also check the rear band...could be broken band or actuator..

the rear band and servo is what gives you reverse...the trans can have the forward gears still..

rear servo..can be repaired by just dropping valve body...
rear band broken...trans comes out...

there are aftermarket servo kits available..

http://www.bulkpart.com/2/product/A904servo/S12912.html

have used the sonnax one in 4 or 5 trans...there more expensive ones available too

http://www.sonnax.com/product-lines/high-performance-transmission/parts/3731

 

[fishy68]

I bet Tony's right. Only other thing it could be is if an ear snapped off the rear band. Either way it's not applying the rear band and will have to come apart.