1990 q45 wont reverse. HELP!

[theBMXhybrid]

Story is simple. Parked my car returning from school. Next morning I started her up put her in reverse but the car just revved.... we tested the the gears : drive,park 1,2,3 works just fine. when put into neutral it doesnt roll backward, and when you rev the car it rolls forward very slowly. my brother and I have replaced the TCU, inhibitor switch and have run the diagnostics on it. diagnostics read that everything is fine. My brother recently replaced the transmission about 5k miles ago as well. SO WHATS GOING ON!?

[Infinitiguy19]

With what type of transmission was it replaced with: New, used?

What is the fluid smell and color?

[qship96]

Replaced transmission 5,000 miles ago with what, another used old tired transmission?

This time spend the green for a fresh nissan rebuilt one if you want to travel another 60-100K miles without repeating labor yet again..........never confuse price with true cost.

[theBMXhybrid]

thank you for the speedy responce. We checked the ATF and filled her up. Its normal color. I know that when trannies get low they tend to act up a bit. My bro I think put in a new transmission. But im hoping we dont need a new transmission. is there something that could be potentially causing this other than bad transmission?

[theBMXhybrid]

I just talked to my brother and he said he put in a REBUILT transmission 6 years ago but only has 5k miles on it. He ownes a BMW 530i now and recently gave the car to me.