I just bought a 94 Accord (automatic trans) a few days ago. I noticed when I was driving it home that when I had to put it in reverse, it would feel like it was in neutral and then it'd kick in and reverse just fine. Today, I went to move it because I had someone coming to replace the brakes and rotors. It shifts fine but it wouldn't move in reverse. After some struggle, the guy got it to reverse but then it wouldn't do it again. He checked the fluid and said that looks fine and doesn't think it's a major tranny issue. He originally said he thought it could be a sensor or possibly the shift linkage but after he replaced the brakes, he drove it up the road and said his best guess would be a loose vacuum hose going to the tranny causing it to do that. Does that sound like it could be the cause? I don't know the guy so I don't know how extensive his transmission knowledge is.

 

Your transmission does not use any kind of vacuum controls. It is electronically shifted via the TCU and there is a throttle valve cable at between the throttle body and transmission.

Shift cable may be broken or out of adjustment.
4th clutch could be defective.
Servo control valve stuck.
Servo valve stuck.
Shift fork bent.
Reverse gears broken or damaged.
Reverse selector worn.

Does the transmission make any unusual noises when placed in Reverse?
Whining or grinding sounds?

Verify your CEL and D4 lamps work.
If so, look under the glove box door for two blue connectors, one will be a two wire connector. Using a small wire, jumper the two wire connector, and turn the ignition switch to II(ON). Observe any blinking CEL or D4 codes. *not all D4(transmission) codes will cause the CEL/D4 lamp to illuminate.*

Verify that your shift indicator lamps light up when the appropriate gear is selected. If not check if the light comes on when not in the illuminated gear.
The console switch may be dirty or the shift cable may be out of adjustment.
Verify cable is in adjustment How to replace the ignition switch or troubleshoot (Honda, Acura)

Further troubleshooting Honda Electronic Transmission Problem- Troubleshoot, Inspection, Repair, Replace..

 

It doesn't make any unusual sounds when in reverse and the shift indicator lamps do light up when in the correct gear. I will check the CEL and D4 lamps tomorrow when I can actually see. I thought it may be the shift cable initially because reverse was totally fine until today and he did manage to get it to reverse after a little work so it's not totally shot but I couldn't get it to go in reverse after he did. I didn't wanna risk messing anything up by trying too hard.