I re-read and never saw your first explanation; If you think I would flush without changing the filter or cleaning the pan then you are mistaken. I would like to know why you said NEVER flush your ATF. Does it have something to do with knocking built up debris loose and clogging something?

 

read my last post

 

there is no real thing as a "flush"
all the machines do is change the fluid which is called a flush
they operate at the same pressure as the trans operate
I'd drop the pan to see what's on the bottom first
changing the fluid when there is a problem never "fixes" anything

 

I have exactly the opposite opinion. I always flush, and I don't change the filter every time. The filter doesn't catch enough stuff to make it worthwhile to change. The fine accumulation that lies on the bottom of the pan does just that, it lies there. It does no harm. There is NO reason to not flush. It changes a lot more fluid than any drain and fill could do.

That's an internet myth that just won't die. It doesn't happen.

Here's the right way to do it: https://www.ford-trucks.com/articles...-transmission/ This was written for a different transmission, so you'll need to adjust the amount of fluid. Also, the AOD has it's cooler line connections top and bottom, not front and rear. I don't remember which is out and which is return.

 

In the case there is a problem, don't you think dropping the pan makes sense?
If everything runs fine, there is no need, I totally agree

changing the fluid is maintenance, not a repair

 

Then you're completely in the dark as to the health of your transmission by not dropping the pan and seeing what has or has not accumulated there. When I change fluid, I drain everything. so you're wrong as to how much fluid gets changed. Sure, take it to a shop and you'll get a quickie job done, both with a flush or change.

 

He knows more about transmissions than you ever will

 

Are you trying to pick another fight ? In one of your posts above, you agreed with me. He may know more than me on some things here (on later model automatic transmissions) , but the fact remains that unless you drop the pan and see what's there, you will NEVER know if there's a potential problem. That position you also stated. As for a complete fluid change, I've already stated my thoughts. If you go to a shop and pay them for a filter and fluid change, you're most likely not going to get a complete change as the guy doing it in most cases will not take the time to do it the way I do at home. But go ahead, keep it up.

 

This is escalating quickly.

I think we can all agree that a dying transmission will not benefit much (if at all) from new fluid regardless of method, as long as the trans is properly full.

This could be wrong, but if the filter is clogged, dropping the pan and changing the filter may help since flow seems important to operation and cooling.

I changed the filter on mine when I dropped the pan since it had around 170k miles (on what I assume is the original filter) for peace of mind. I did not flush it but replaced at least 5 qts and had no issues before or since.

We are all entitled to our opinions but personally I couldn't sleep at night if I didn't drop the pan to see what's inside. If I knew if the fluid had ever been flushed, I would agree that dropping the pan may not be necessary since it's very messy especially without a drain plug like mine.

I also drained and refilled or flushed all fluids on my van from coolant to differential after I got it. Obsessive and excessive? Probably.

 

If the filter is clogged a new one won't help. The only way the filter can clog is if the transmission fails and loses the friction material, which ends up in the filter. At this point, the trans needs a rebuild, not a filter.

Five quarts out of the 12-18 quarts it holds, depending on which transmission you have.

I agree.

 

Good to know, so neither a filter or fluid will help a dying transmission? Are filter replacements generally made for after a rebuild?

Right, I was aware there is a lot of fluid still up in there (4R70W holds 13 qts IIRC) and intend on flushing it sometime. Something is better than nothing I thought and the old fluid wasn't burnt looking or smelling yet so possibly it was flushed before. No records, bummer.

Some of us have opinions, experts have facts...

 

A lot of information from a lot of different backgrounds and experiences; I like it. I am defiantly more on the amateur side of working on these vehicles, so I appreciate the input here. I got this van on an auction deal from the state of Ohio govt surplus auction, believe it or not, there isn't a ton of rust. It was the city carpenters van, I believe. It had been sitting for almost 2 years before I bought it. At my old job we had a mechanic on staff to work on fleet vehicles and I had him look it over. I think he's a bit lazy and said not to change the fluid, it looked fine and called the shifting strong. I have doubts and think that around 60k I can change the fluids to be safe.

Since this is a new vehicle to me, I plan on removing the pan, etc to see whats going on inside and do a flush like described in the Mark's posted link. I'll use Mercon V instead of the discontinued Mercon. Next time I probably wouldn't take off the pan unless I'm having problems to do an inspection. All the fluid appears to be fine just looking at it, but I systematically flushed and replaced the coolant already. first thing I did was replace the oil filter and and oil, added lucus oil treatment to it. I also replaced the engine oil temperature sending unit as it was malfunctioning.

 

Neither a filter nor new fluid will replace friction material that has worn off the clutches. It takes a rebuild to fix that.

I think most of them are used by people that like to change them. It just isn't necessary in most cases. Newer transmissions have real filters that do need to be changed.

 

So now that we know this is an AOD you should also investigate the calibration of the TV cable as this will affect shift firmness and rpm to some extent. There is a minimum cable preload that translates into a minimum line pressure that it should not go below as this would allow the trans to slip and prematurely wear. But given your description of the trans behaviour it is possible the TV preload is a little high at the moment. The adjustment mechanism for the cable is at the throttle linkage on the engine, before you touch it be aware that it is spring loaded and small adjustments produce large changes so you don't want to move it more than 1 notch at a time and to do that you want to mark it with something so you have a reference.
All that said, a firm shift is not a bad thing with this trans, the factory calibration for buttery smooth shifts didn't help durability which wasn't great for these. It is also possible your trans has a shift kit, if shifts are hard and quick in all gears at what seems like normal rpms then this is a good possibility, if however you have to rev the motor excessively to get a shift and downshifts bog the motor then the TV cable needs adjustment.

P.S. Just revisited you first post again. A jolt when shifting from park to drive suggests idle speed is too high, these early EFI motors had a high speed warmup idle(which I always hated) but it should drop down to about 700rpm after 30 seconds or so, if your idle never comes down then you have another issue to investigate.
And the late 1-2 shift suggest a TV cable adjustment issue.

 

That's the good information I'm talking about! I'll do some investigation as I know these older vans require tune ups every now and then. Vehicles today don't need this tune up procedure so I'm skeptical of taking it anywhere for a "tune up." Is there a checklist somewhere for what needs to be done in order to tune these machines?

Also I'll investigate the TV cable and rpms. I think I may be shifting right from Park when I start the engine. I do know that the rpms defiantly go down after a while, I noticed it when I did the coolant flush two weeks ago. I'll update everyone next chance I have.