98 S70 145,000 on the odometer

Auto trans will not shift into reverse but only intermittent.

How do I troubleshoot to determine if I have a tranny problem or if it's the PNP/Gear Selection Sensor? The PNP switch is about $175 so I don't want to go out and buy one to try it only to find out the tranny is bad.

Can the PNP switch be serviced? In other words, is there anything I can try (cleaning contacts?) even if it's only temporary that will tell me I really should replace the switch? (Went to AutoZone for free code reading. They gave me results for a 2001 Saab. Nothing wrong there. Volvo dealer wants $129 to give me the codes.)

Can the tranny be diagnosed without a lot of work (and expense)?

If the PNP switch is bad, will it prevent the tranny from going into any other gear or just reverse? All other shifting is fine, no clunks or bad noises. Fluid level is right on. Fluid is a little dark but not bad.

Anything else I can check as to why reverse only works some of the time in my driveway before spending big transmission bucks?

Just in case, anyone know where I can get a used or rebuilt transmission and how much I'll pay for it? What about transmission installation? Does the whole engine have to come out?

Thanks, Bill

 

Hey Bill, welcome to the site.

You have a lot of questions there, lol, kinda scary.

If the trans is not slipping, I would think it is something else. Some people do clean/service the PNP switch.