the general consensus of folks who really know, is that you shouldn't 'power flush' a tranny.. this is really really bad juju.. it dislodges particles your tranny is using for friction.. And, it usually it's done in a reverse flow manner which isn't real good for valves..

you should drop your pan and allow gravity to drain the fluid- it won't get it all.. this is fine.. you should change your filter.. you should do this at least every 30k miles..

it's my opinion- and my opinion doesn't weigh much as it's wrong more often that it's right: if your adjusting bands, the end is near.. it's sorta like cleaning your ears: either you do it at every interval (along with a flush in the right direction), or you don't do it at all..

the mysteries inside a tranny are a lot more complicated than the act of doing good preventive maintenance.. and other than the check delete (which I still haven't done, dang it) it's all listed in this thread.

 

I always start mine in neutral after it sets for several hours or more.
Fluid gets circulated before I put it in gear.

 

So do it regularly and keep it up, or don't mess with it just because. I'm not experiencing any problems. But when I get a new truck I want to know how well it helps to do the preventative maintenance.

 

yup.. so long as that TC isn't starting out dry, and you have a good circulation going on before you start abusing it..


and- by the way- I didn't know ANY of this before I started hanging out in this joint.. This is one of the reasons I hang out.. you pick up some good stuff along the way.

 

Could you explain under which circumstances the TC would be anything less than 1/2 full of fluid? Your statement above suggests that the TC will drain itself dry while shut down,(not rotating) for extended periods.

While you are at it, please elaborate on the "dislodged particles" the "tranny is using for friction".

With all due respect, that's a pretty long straw you're using to blow smoke up someones ****.

 

Apperently you know nothing about these transmissions? There are some guys on here that recommend doing so. I would never take off with out my converter being half way on fluid. Ever let your truck sit in the cold for a week or so and start it up right away and drop it in reverse? most of the time it will not engage.

 

When a tranny gets up in the miles, there is a lot of burned clutch material floating around in the fluid that acts as a friction modifier of sorts. Completely draining the fluid removes this helping hand, and thus, shortens the life of the tranny.

That is one of the reasons why it is recommended not to do a full flush on an old transmission that hasn't been serviced at regular intervals (that and the whole reverse-flow flush thing....but that's another issue).

If it hasn't been well maintained, it is better to change just the fluid in the pan and the filter.

 

Of course! If you take care of the transmission and change the fluid every once and a while, the fluid doesnt become contaminated with clutch material and dirt. If the fluid doesnt become contaminated, the check valve doesnt become clogged and impedes the flow of fluid to the trans cooler, dirt doesnt go in between the clutches and score them, and dirt doesnt clog up the valve body.

I dont believe the "power flush will ruin your transmission" hype because transmission fluid, especially ATF+4, carries contaminants, right? Well, when it is "power flushed" the fluid will carry the contaminants with it to the machine. But thats just one man's theory.

 

Know that I respect you even if I am pointing out just now that the factory service manual disagrees with this specific opinion of yours: Band adjustment is scheduled maintenance.

I believe it makes sense to adjust the bands on schedule, since they're covered in clutch material that wears away over time and there's only so much range of motion available to the servos that engage them. (Drum brakes are a good analog: Without self-adjusters to do the job for us, brake adjustment would be a periodic maintenance item just as it is on big rigs.) Once you run out of servo stroke, the clamping force of the bands is reduced, which leads to slippage, accelerated wear, friction material circulating in the oil to do damage throughout the machine, and band anchors falling out of place into the pan. Adjusting the bands ensures that you get back to design specification clamping force so the transmission behaves as designed and doesn't wear out so quickly.

For everyone else: One of the failure modes of these beasties (automatic transmissions, not 46R's in particular) is internal leakage. This is often caused by friction material circulating in the oil, grinding away where steel valves and pistons move within aluminum bores, catching between clutch frictions/steels to score both as it rolls between them during engagement and disengagement, and generally fouling up everything that relies upon the lubrication quality of the ATF. Friction material circulating in the oil is NOT a "friction modifier" or leak sealer. It's a bad thing. If you're counting on friction material circulating in the oil or sticking in worn passages to prevent leaks, your transmission is already a goner. Wouldja rather schedule the job at your convenience in the near future or be forced into it by a sudden dramatic failure? And who the hell wants to drive a truck that can't be counted on to go wherever you want to take it at a moment's notice anyway? Not me!

Myself, I always always always add remote filters into the cooling lines of juicers, primarily to keep dislodged friction material from circulating into and causing wear in places that require lubrication. It's a very cheap way to get a lot more life out of the machine.

Disclaimer: I'm no transmission expert. I've rebuilt a handful of 'em, mostly 727's and TH400's, but I believe that my experience transfers well enough to the 46R's to be applicable. I could be wrong, and I'm always willing to learn from those who know more than the little bit that I do.

 

Bada bing, bada boom. Improper adjustment of the transmission bands will cause certain failure, not proper adjustment.