A car that won't move when in reverse could indicate a problem with the transmission. It could also indicate a problem in the gear selector.
it will drive but when in reverse it wont move
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If you have an automatic transmission, it probably has a forward clutch/band problem.
Reverse, Drive, Low gears
why reverse wont go in on 2004 town car
Best guess, your Transmission is shot. You'll need to call a mechanic and tow it to the shop to get it checked out
For the Reverse problem, you could have low transmission fluid, or a bad transmission. For starting in drive, just about every modern car will not start when the transmission is in gear. They will only start in Park or Neutral. This is a safety feature to prevent the car from taking off into someone or something when started.
truck will only go forward not in reverse does this mean the transmission is gone
Drive...
No
Your shift linkage may have slipped or become loose. Check your linkage.
crankshaft