Here's a bit of worthwhile reading on manual transmission fluids:Fluid Options:
I've personally used AMSOIL 75W-90 GL-4 MTF and AMSOIL Synchromesh and had great experiences with both in the past. In the 124 Spider, I'm using the 75W-90 GL-4 MTF. At the time of this edit, I've been using the fluid for two years and am pleased with its performance.
The 75W-90 GL-4 can be a bit stiff on cold mornings below ~40F in freezing temperatures for the first mile or two, but works well in hot conditions and with severe driving. The Synchromesh fluids can be a bit more notchy when very hot but will shift better on colder mornings than the 75W-90 will, at least until the transmission warms up a bit, and will be better suited for normal driving conditions. However, Synchromesh fluids mighit have lower EP additive concentrations and as a result, may not be well suited for exceptionally severe driving, frequent racing, and modified cars where hard launching and shock loading are the norm. I personally use the 75W-90 since I only drive the vehicle in warmer weather and it stays in the garage over winter.
Some people have also reported good experiences with the Ford XT-MS-Q5 fluid, which seems to work well but is a tad more expensive. Other synchromesh fluids may work as well. Choose the fluid that's best suited for your driving conditions. Note that this same transmission in the NC Miata used a 75W-90 GL-4 MTF, so that's what I'd recommend sticking to.
Pretty normal to have some swirls and some metal on the magnet. No big deal as long as you're not finding large chunks. The occasional pieces that you find are usually from grinding gears or something similar. Oils can't prevent hard parts from breaking like that.Just changed over to Amsoil 75W-90 from Synchromesh. The old Synchromesh fluid has some swirls on top and sparkly deposits at the bottom, and the magnetic drain plug has enough shavings attached to coat just the tip. The biggest piece of metal I found in the fluid is about 0.5 mm. Not sure if this is considered bad, I've done maybe 3 track days with the Synchromesh. It did do a pretty good job keeping shifts smooth throughout the cold winter we had. I don't plan on winter driving my 124 anymore, so will go for something more geared towards high performance use.
I think you'll find them to be pretty much identical once the 75W-90 GL-4 warms up with some abuse. I think your recommendations are spot-on.Just test drove with the Amsoil 75W90. Synchromesh is slightly smoother and slightly less notchy than 75W90, but the difference is hardly noticeable. Both fluids are way smoother than the OEM fluid. All I'm looking for is suitability for track use so I'm happy with 75W90. I'd still recommend Synchromesh for people who prefer comfort, don't push the car to extreme limits, and occasionally encounter low temperatures.
I just changed my manual transmission fluid recently and had a heck of a time even with the pump I bought. I don’t think there is space to get in there with the easy pack. My pump was only pumping half the fluid out of the bottle before it would quit.I think you'll find them to be pretty much identical once the 75W-90 GL-4 warms up with some abuse. I think your recommendations are spot-on.
It's worth noting, the 75W-90 GL-4 Manual Transmission Fluid is now available in AMSOIL's Easy-Pack packaging, which means you won't need a pump to service this transmission. That's an industry first and a significant cost and time savings in servicing the transmission.
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Trust me there's space. I did my buddy's BRZ recently. The whole nozzle flexes. You need like 1" of clearance max to get the nozzle in the hole, probably less. You squeeze the bag from the bottom and it just fills it all in.I just changed my manual transmission fluid recently and had a heck of a time even with the pump I bought. I don’t think there is space to get in there with the easy pack. My pump was only pumping half the fluid out of the bottle before it would quit.
Not needed. Just refill until it starts coming out of the fill hole. On relatively level ground, the fill hole doubles up as a level port.Hi all, just a simple question. If I collect ( of course) the oil coming out from the drain and measure the quantity on a graduated bottle , is it correct to replace the exact amount that came out with fresh oil? That would be more than exact , right ? I ll be using a syringe .