MOTORCRAFT changes transmission oil from SAE 75W-90 to 75W-140


GT@50

GT Owner
Mark II Lifetime
Dec 14, 2019
941
Issaquah
Since this thread has been revived, I'll suggest something else to all of you. Do oil sample analysis of the trans fluid too. I did with Blackstone the last time I changed it. Their analysis was that it was a little high on some metals, but that I needed to do another sample next change to start to establish the baseline. The oil plug had some fine fuzz on it, but no chips. That's about what I'd expect for a manny tranny with synchros. Synchros do wear and produce fine fuzz. I'm coming up on 80,000 miles.

I have already gone to extended engine oil changes based on oil sample analysis (10,000 miles). I plan to do the same with transaxle fluid, based on the results of the next change (due around 90Kmi.). Unless some EP components are degrading, I don't see why the fluid should be changed every 30Kmi automatically.
Manual trannys make metal. Every time you shift, you're engaging and disengaging gears and little bits are created. No big deal on most trannys but on the GT there is a pump and a screen. Keep that screen clean. Restricted screen is restricted lube. An excessively dirty screen may let metal through which will hurt the pump, and make more metal, which hurts your wallet, and pisses off your wife.
 
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HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Since this thread has been revived, I'll suggest something else to all of you. Do oil sample analysis of the trans fluid too. I did with Blackstone the last time I changed it. Their analysis was that it was a little high on some metals, but that I needed to do another sample next change to start to establish the baseline. The oil plug had some fine fuzz on it, but no chips. That's about what I'd expect for a manny tranny with synchros. Synchros do wear and produce fine fuzz. I'm coming up on 80,000 miles.

I have already gone to extended engine oil changes based on oil sample analysis (10,000 miles). I plan to do the same with transaxle fluid, based on the results of the next change (due around 90Kmi.). Unless some EP components are degrading, I don't see why the fluid should be changed every 30Kmi automatically.
PeteK.
How often in time or miles are members doing engine and trans oil changes.
Most owners probably drive 500-2,500 miles per year.
I could see a 500 mile per year car doing a engine change every 2-3 years and yearly for driven cars

not sure on the rules for trans change.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,470
Kalama, Free part of WA State
I stick to 30kmi for trans oil change. I’ve done it 2 times. So far….

But, yeah, most people won’t change it on miles, but on time. Even so, yearly is overkill. The oil is good for more years than that. Blackstone agrees.