I feel like I may be reading conflicting information. I have read through various threads on here talking about flushing transmissions and that it is a bad idea if it has high mileage. With 261k I'm thinking this would apply to my rig. Is the supposed "bad flush" referring to the power flush or is it a bad idea in general to do this even if I plan on using the trans pump one qt at a time method? I can't imagine leaving dirty old fluid in the trans forever would be a good idea either. I'm also thinking to add a bottle of lubegard black as well, says its for honda and toyota trannies...thoughts?
Thanks again all.
IMO is a difference between a "flush" and a simple "fluid change".
I am fairly sure or at least my understanding is that a flush consist of either back flushing, running the fluid back in reverse and or also running a solvent through it. There is also I believe a positive pressure that pushes the fluid/solvent through. Frankly I am not sure if there are many places that even do this anymore as it is a pretty outdated method.
A full fluid change is just that, either a T-Tech type machine which uses the transmission cooler lines then just uses the trans own pump at no more pressure than just normal operation.
If you use this type though I would really drop the pan first and fully check it out then replace the fluid.
Or if you can find one really the best method is the
"pump inlet flush" type machine, that way they remove the pan anyway and it gives a better replacement of fluid, probably 95% or more, the T-Tech probably 85% or so (just a guess on my part). quite a bit of the fluid in the torque converter remains using this method.
Or you can get someone to help and do the replace a qt at a time method through the cooler lines. Same result, probably 80% is exchanged
I think as long as you get a good solid 85%+ fresh fluid in there without using any solvents or back pressure just the trucks own pump then you should be good to go.
And instead of Lubegard I would just use a quality 100% synthetic fluid.
Here is something I found that seems to explain this a bit.
Transmission Flush, When and when not to flush transmission | MDH MOTORS
Automatic Transmission Flush
If you really want to do it right and use the very best method then go with a proper pump inlet machine fluid change, probably need about 16Qts of fluid and use 100% synthetic ATF like Amsoil or Redline.
Thats probably somewhere in the neighborhood of $200 for fluid then probably somewhere between $100 to $150 for the pump inlet flush.
So $300-$350.
and no reason to change the trans filter because we don't have one, just a simple screen which should look like brand new unless something is seriously wrong with your trans.
