Hello, I am new to the volvo seen and just bought my first volvo. It's a 85 245 wagon 4 speed manual. I was wondering if I can change it to a 5 speed one. My wagon currently doesn't have reverse and the gears make tons of noise so I just figured I'd get a new transmission. Also do I need a different drive shaft

 

Is there not a button on the top of the shifter?

If not and your shift **** does not have a 5 on it - you have a m45 4speed.

So, yes you can replace the 4 speed with a 5 speed. Volvo had two choices, the m46 with a laycock electric overdrive, and the m47 aluminum case unreliable pure 5 speed. Either one will work with the correct driveshaft, the M46 needs an additional relay, wiring and switch. The m46 driveshaft uses three traditional u joints, the m47 has a tripod - ish rubber coupling at the transmission. M47 is less common than the M46, The M46 overdrive wears out and may not actually work in 2021. The OD unit can be fixed but it's expensive. Either way on a 1985 i think the speedo still has a cable (correct me if i'm wrong) so the speedometer with either trans will be wrong. The differential ratio installed with a 4 speed is not what's installed with a 5 speed. I converted a 78 4 speed M45 to a M46 and the speedometer was never correct, and I had the choice of all the speedo gear part numbers.