I have an Aisin-Warner transmission in my Montero, which used to shift pretty harshly before I took over the maintenance. Whether that was due to the cheap stuff the dealer was using at the time or just the 'nature' of the unit, I do not know.
Initially, I switched to Motorcraft Mercon V and did a cooler line flush. Although there was no major change in the shifting/performance, even after an ARX treatment, the fluid always came out cherry red. The pan and valve body looked all clean and shiny post ARX. At one point, there was an excellent deal going on and I picked up Mitsubishi SP-III for dirt cheap. Again, I did a cooler line flush and got 8 litres (total capacity) of fresh fluid in there.
The unit continued to shift the way it did for a couple of hundred miles until the shifting really smoothened out to the point where you could not feel the shifting. My initial thoughts were I should have used this stuff right at the start, considering the difference. But when I checked the ATF as part of my routine inspection of fluids, it smelled burnt and looked very dark. It scared me, so I did a cooler line flush the same day. Part of regular maintenance, I did another cooler line flush after 25,000 miles and again you could smell the stuff yards away, and it came out all dark brownish red. After the third cooler line flush, the oil started coming out cleaner thereafter, but never like the Mercon V I initially put in.
Checking the fluid this afternoon, with 17,255 miles on it, it was dark and the smell was burnt. Drained 5 litres of the stuff and put in some ACDelco Type III H I had in my stash, since the manual calls for Dexron III. I've kept a small sample of what I drained out for an analysis, and I know many have commented on how SP-III wasn't all that good...but does it have some sort of strong cleaning agent as part of its additive pack? I'm not all that informed about hydraulic fluid, but the improved shift quality after using the stuff and the condition of the fluid has me thinking this. Might not have a long life span, and I cannot tell because there is no UOA, but it seems to do a good job of keeping the unit clean (pan, magnet and internals are all sparkling clean).
Initially, I switched to Motorcraft Mercon V and did a cooler line flush. Although there was no major change in the shifting/performance, even after an ARX treatment, the fluid always came out cherry red. The pan and valve body looked all clean and shiny post ARX. At one point, there was an excellent deal going on and I picked up Mitsubishi SP-III for dirt cheap. Again, I did a cooler line flush and got 8 litres (total capacity) of fresh fluid in there.
The unit continued to shift the way it did for a couple of hundred miles until the shifting really smoothened out to the point where you could not feel the shifting. My initial thoughts were I should have used this stuff right at the start, considering the difference. But when I checked the ATF as part of my routine inspection of fluids, it smelled burnt and looked very dark. It scared me, so I did a cooler line flush the same day. Part of regular maintenance, I did another cooler line flush after 25,000 miles and again you could smell the stuff yards away, and it came out all dark brownish red. After the third cooler line flush, the oil started coming out cleaner thereafter, but never like the Mercon V I initially put in.
Checking the fluid this afternoon, with 17,255 miles on it, it was dark and the smell was burnt. Drained 5 litres of the stuff and put in some ACDelco Type III H I had in my stash, since the manual calls for Dexron III. I've kept a small sample of what I drained out for an analysis, and I know many have commented on how SP-III wasn't all that good...but does it have some sort of strong cleaning agent as part of its additive pack? I'm not all that informed about hydraulic fluid, but the improved shift quality after using the stuff and the condition of the fluid has me thinking this. Might not have a long life span, and I cannot tell because there is no UOA, but it seems to do a good job of keeping the unit clean (pan, magnet and internals are all sparkling clean).
