I buy PP HM Full Syn ATF from the local Shell distributor for $4.10/qt. Approved for both DEX IIIH and JWS 3309 specs.

I doubt there is a significant difference in the "Platinum" fluid. As Spook suggests, either would be fine, as would any major brand ATF.

You need to confirm that whatever ATF you choose meets Dexron specifications. That will be stated somewhere on the container. I think Dexron III was Volvo's spec when your car was made. Subsequent Dexron specs are fully compatible with earlier ones, and the latest is Dexron VI. It is an improvement over the older stuff. The petroleum-base Dex VI has characteristics close to synthetics, and there may now be synthetic Dex VI.

I found a big difference in flow rate when flushing the AW30/40 in my S90 compared to the AW71-L in my 940...it pumps out a LOT faster so be ready for that. I needed about 10-12 litres of new ATF before clear, red fluid came out, indicating a complete flush.

I used Valvoline MaxLife ATF (Dexron VI) in the latest S90 trans flush.
--
Bob: Son's XC70, my 83 244DL, 89 745 (Chev LT-1 V8), 98 S90 (recently sold) and 2010 XC60. Also '77 MGB and four old motorcycles

Dear jaydee,

Hope you're well. Generally, it is a mistake to economize on working fluids, i.e., brake fluid, oil, coolant, gear oil, and automatic transmission fluid (ATF). These materials protect mission-critical parts, some of which costs thousands to replace or rebuild.

That said, I cannot imagine that any Pennzoil ATF will do any damage at all, or that there's a significant difference between it and, say, Mobil 1 ATF.

Major US autoparts stores usually have sales which cut the price of ATF by 25%, making Mobil 1 ATF no more costly than Pennzoil ATF.

Hope this helps.

Yours faithfully,

Spook