Filled with Castrol Dexron VI in 95 BMW 525i

[Russell]

This is repost. I posted somthing similar is it just seemed to have disapeared.

I just had my independent BMW mechanic, DRAIN fuid and flush my trany oil cooler (with air) after 35,000 miles on the current fill of Mobil 1 Dexron III synthetic atf fluid. Trany is the GM made (in France) automatic 4 speed transmission. Mechanic said the old fluid was very clean did not look burnt or dark.

He then filled with 7 quarts of Castrol Dexron VI which is a synthetic blend. Car runs fine so far. Very smooth and responsive. We will see after a couple of thousand miles. http://theoildrop.server101.com/forums/images/graemlins/smile.gif

There has been some concern that you should not use Dexrion VI in older cars that required Dexron II. Valvoline said it was fine to use. Castrol was non-commital yet the bottle and web site stated backward compatible. and my BMW dealer said it was fine.

[ryan roopnarine]

as someone that changes their transmission fluid every (or every other) oil change, i always found that when i had the box filled with predominantly mercon v (more semi synthetic than dexIII-merc) that though the shifts were a bit smoother, the box would seem to run hotter. this is on a 1991 production a4s 310r. i stick to dexIII now because it is a good deal cheaper than either the 6 or 5, and dealers seem to be in the process of clearancing it out for the new dex 6 stuff. i have two cases worth of the dex iii, at least, that were bought for $.95-$1 / quart. if your mechanic is going through the trouble of blowing your cooler out with compressed air at every change, are they using a cooler cleaner when they do so?

[Russell]

Good question. There was nothing specific on my invoice for a cleaner. However, I will call them Monday. I never knew there was such a thing as a cooler cleaner. Can you tell me more, even a brand?

[ryan roopnarine]

http://www.autobarn.net/noname8.html

advance auto has been closing this product out for $1.50-$2 a can. i guess a shop might be reluctant to use it if they didn't have the right adaptors to hook the can up to the size fittings on your car's transmission cooler, but i'm sure that some other product can be used explicitly by spraying into the cooler. you'd put the fitting onto the can hose, attach to the cooler, spray in, wait for it to drain, and blast clean with compressed air.

[Paul in NZ]

just blowing the old oil out arent they?Prolly doesnt drain that easily

[Russell]

just blowing the old oil out arent they?Prolly doesnt drain that easily
Not sure what your point is? Yes the oil would not drain out easily from an oil cooler. By removing oil from the cooler they can replace more fluid than a standard drain and fill which only removes about 3.2 US quarts. Even so, it still leaves at least 2.3 quarts of old fluid.

[Russell]

Thanks, Looks like it should be used if you are rebuilding your trany and seems like a good idea even on regular serviceing. However, I suspect they feel it is not necesary on reqular servicing. In fact, most shops, including the BMW dealer, would not even blow out the cooler. I will bring it up next time I have the car serviced. Good idea.