I tested my alternator on my '97 850 and realized it needs replaced. Since I don't wanna pay 200 bucks give or take for a new one, so I was wondering if I can use an alternator out of 5 speed in my automatic Base model 850?

 

Out of a 5 speed what ?? Volvo 850 ? What year ? Which engine ? Turbo ? Is yours a base 850, GLT, T5 or R ? What is the one it's coming off ?

If you want a good answer, you have to give good info.
I'm going to end up doing what you could. You tell me what and I'll mine three auto parts stores web sites to make sure they agree and give you some options.

 

If yours is a 2.3 turbo like mine it should be a BECK/ARNLEY Part # 1860819, BOSCH Part # AL0053X and others.

The Bosch interchange says yours will fit these and they will fit yours:

VOLVO 850 (1993 - 1997)
VOLVO 960 (1995 - 1997)
VOLVO S90 (1997 - 1998)
VOLVO V90 1997

 

Sorry I said mine a Base 850 and its a 5 speed 850 but I'm not sure of the model