slipping fifth gear

I have Infiniti G20 '92. My 5th gear is slipping and I am wondering what needs to get fixed and what price range is feasible for the repair. I already got a quote from AAMCO transmission here in Chicago ie $800.
Please help me with more info. Thanks.

I just got mine done!
I bought a tranny with 63,000 kilometres on it and it feels good.
Although it costed me $1700 canadian

The P10 G20 is notorious for the "5th gear slippage." Try using the search feature on AF to find the old threads about it. Also, try SR20.net for information.

Hope that helps!

All early SR20 trannys are known to do this. Expensive or don't drive in 5th.