I need to fill my 5 speed manual. I did a search and found no apparent consensus.

AutoZone lists the fluid as dealer only. O'Reilly's lists 75w80. I've read that synthetic is recommended, but their listing doesn't specify synthetic.

I'm having trouble finding 75w80. I found 75w90 Delo synthetic, but for every thread that says that's acceptable, there's another that says not to use it. Same with Mobil1 5w30...one thread says it's ok, one says no.

I finally said screw it and called the dealer to get the Volvo stuff. Aside from the fact that my closest dealer is over an hour away, they have to order the fluid because they don't stock it.

I need this car running ASAP. Any input appreciated.

 

manual transmissions use gear oil - typically in the 75w90 range so the 5w30 is referring to motor oil. You can find the exact specs in the owners manual but I'd expect you should be able to use a GL5 synthetic such as Redline. Note the numbers are the viscosity range at low/high temps, and with synthetics being more tolerant of temperature variations, I'd expect the factory 75w80 to be replaced by a synthetic GL5 75w90. Shop the Volvo friendly sites like eeuroparts or FCPeuro to see what they offer for your model/year. Use the SAE/MIL specs from the owners manual as your guide. The "compatibility" question goes back to the fact that the syncro rings in the transmission are softer than the gears (ie they have copper in them) so the specs for transmissions are different from those for differentials (which don't have syncro rings).

I did the Redline GL5 synthetic 75w90 transmission gear oil when I did my Audi's 5 speed and it was a noticeable improvement - particularly on very cold mornings. I put over 250K on that car too...

 

Yeah, 5w30...I don't think I would ever consider it, but like I said, there's multiple threads on multiple sites where people swear up and down that it works great. Same with the 75w90...people swearing that it works fine, and others swearing that the 10 point difference between that and 75w80 can affect shifting.

As for the manual, it basically just says to use Volvo approved fluid. I'm still a bit annoyed that my dealer doesn't stock transmission fluid, but that's a whole other issue as it's just one of many gripes about my "local" dealer.

I did see a thread where someone advised not to use GL5 fluid because it does bad things to soft metals (brass, copper) in the transmission. Apparently GL4 is formulated in such a way as to not cause these problems.

In the end, I found myself in Portland and just got the OE stuff from IPD. It's 75w80, GL4. Forty bucks worth, as opposed to the $15 I would have spent on the Delo 75w90, which kinda sucks.

Thanks for the input.

 

Red Line Synthetic Oil - Gear Oil for Manual Transmissions - MTL 75W80 GL-4 Gear Oil