Heard from a different forum that GM auto trans (particuarly the 4L60E or 700r4 thats in the s10 blazers) that requires the dextron fluid if you drain and flush the lines then put ford type F fluid in it will shift a bit harder but less slipping of the clutches. An older guy on the forum said hes been doing that for years with no problems over 90,000 miles. (180K on his truck so its well worn in)
i tried the procedure on a 4L60E once. it seemed to do the trick, however, i would not go for a complete flush and refill. all i did was drop the pan and add(top off) the type F. i would guess too much type F could do damage?
Nitpick: It's Dexron, not Dextron. There's no 't'.
I googled it. Of course there's the normal collection of "try this", "don't mess with this", "this improved it a little", "this made it a little worse", "this makes the sky rain money in your yard", and "this will eat your children"...but here's what I found that is of technical interest and seems plausible:
Let me restate this, all clutch/band material have a certain amount of slip from the beginning of the shift, and this is normal. When using the Kevlar material though, it acts like you are using type "F" fluid in this unit, a lot of slip at the beginning of the shift, and then all at once (at the end of the shift) the band/clutch comes on. This is why there is so much more "feel" to the shift. I have talked to the tech at Borg Warner, Raybestos, and Alto on this over the years, and the thinking is pretty much unilateral, they do not like Kevlar, and/or Ford type "F" fluid with the clutch/band material that has been offered over the last couple of decades. The Dexron type of fluid starts the apply at the beginning of the shift, and all of the way through the shift. That is why the smoothness of the shift with Dexron fluid. Their dyno results have proven this, and my results concur. Your results may/will vary.
The regular B&M Trick Shift is a Ford type "F", it will not help the clutches or band in a 700R4 or 4L60E. The reason it appears to make it "shift" harder is that it slips more at the bginning and through the middle of the shift and it allows the clutches/band to come on all at once at the end of the shift. The Dexron III has a smoother transition through out the entire shift, which is what you want.
Borg Warner tests show that you lose about 13-17% holding power in "dynamic" situations, (clutches and bands used that come on & off as in a shift). The reason it "appears" to improve a shift is that the clutches/band slip longer during the shift and come on all at once at the end of the shift.
I also read one post claiming specific ways that it is incompatible with some plastic parts, although nobody who uses it
Conversely, I found this:
It's has a gritty feel to it.
maybe colonel can jump in again but that gritty feeling is probably friction modifiers. which if you feel them is probably a good thing. yes i know friction leads to heat but you can curve that with a tranny cooler and or a deep pan also friction means less slipping. i may be off on that but it makes sense to me if it reduces slip and if a big time tranny specialist like yank recommends, it i'm gonna go with it.
Everything I read while looking that up leads me to believe that it is acceptable to mix the fluids rather than trying to do an impossible 100% flush.
In my experience and in my opinion, the 4L60E is absolutely fine under these conditions:
- Not exceeding stock power output by a whole lot (if so, use a 4L60E from a more powerful application; they aren't all the same inside).
- Keep fluid maintained per schedule, using the recommended fluid.
- Keep temperature down. I know that technically it needs to be up to operating temperature, but I can't argue with results: the lower, the better.
Mine, which came with my 2002 GMC Sierra 1500, has 200,000 miles on it including some towing at my 14,000 pound GCWR in mountains. Recently I even ran it a short distance while it was so low on fluid that it was slipping severely...after fixing the leak (from an over-wrenched corroded cooler line) and topping it off it works fine.
Of course, if you're using a significantly internally modified transmission then your fluid needs may differ.
If it's too late and it's already failing then you haven't got much to lose, just the cost of the fluid...
well they came factory but generally the people who know how to shift manual and voulenteered to buy one keep them forever untill thier about ready to fall apart.
there are several variations of the 4l60E, the fullsize trucks got a beefier internals and different clutch plates (bigger i belive) to handle the V8 and towing capabilities. the blazer got smaller /cheaper internals so they just dont hold up...