For the second time I've experienced an unusual downshift with my turbo wagon.
While traveling uphill ( I live in the mountains) the tranny downshifted into 3rd gear at about 50 MPH.
After slowing down to around 40 MPH it again downshifted to 2nd and would only upshift when the RPM's reached 4000+
After about 10 0r 15 miles like this, it downshifted to 4th and operated normally for the rest of the trip.
It feels like the transmission mode switch was changed to sport mode from economy.
However, changing the settings on that switch made no difference.
Both times this happened I was driving uphill after having driven to a lower elevation and returning home to a higher elevation.
Could this be a sign of a bad mode switch or a bad tranny solenoid??

Good tranny info at: www.babcox.com/editorial/ic/ic40238.htm

Did you get a trouble code (check engine and/or flashing arrow)?

No TCU (A1) codes yet.
The CEL is on but for A2, 535 and 413
I think those are separate issues

Another area that you might want to look at is the TPS. I had similar issue during highway speed and no code was logged. It turned out to be a bad TPS.

Ching-Ho Cheng
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1995 855 NA, Bilstein Strut & Shocks, Volvo Protective Grill, K&N Filter, E-Code Lens, ClearCorner Light, Alpine CD-Changer, AutoDim RearView Mirror, 6000K HID

I'd say it's time for a tranny fluid flush.
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.

Maybe but I don't think so
The guys at the jiffy lube looked at it and said the color was good and it didn't smell burned although it did have a funny smell.
Someone may have added something to it.
I'm thinking it is an electrical problem.
No codes though

I would never take my car to a Jiffy Lube or trust anyone's opinion who works there. Most of these guys are taught the bear minimum. I know circles more than they do about most cars and that's not much.

If you search here you can read many Jiffy Lube, Bubba Lube, etc. horror stories.
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.

Gotta trust someone.
Since these guys are my "neighbors" I'm not too concerned about their qualifications.
Especially since I also know something about tranny fluids.
Changing fluids can't hurt thogh and I may do that anyway.
But I'm not too optimistic about solving the problem with that

Its simply called the need for a GEAR POSITION SENSOR-

Thanks for the thought.
I've replaced the gear position sensor b4 on another 850.
So I'm familiar with the process.
I would try cleaning the contacts first and look for a code before replacing the sensor.
Since I'm not getting a code, yet, think I will wait on the replacement

I am going to change the tranny fluid
I have no idea if or when it was done but not optimistic about solving the problem that way

Great write-up for changing the tranny fluid:
http://www.matthewsvolvosite.com/chat/phpBB2/viewtopic.php?t=8767
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.