I've done gone synthetic in tranny & engine (3mpg increase)
 

i;m squealing like a little girl..
more-so because i know i bought a 130K mi car >5 months ago that has never had a transmission oil change.. so i also went synth engine oil.

edit: so far 3mpg FE increase (11.5%).

Q: aren't almost ALL automatic transmission fluids these days synthetic?

A: idk, but i have no doubt that my 1986 car had 1986 tranny oil in it.

I don't have my spec book handy, but there are a few that still use the older formulations.

One note about going synthetic: Not all fluids are compatible with synthetic fluid. Ford had an issue with torque converter shudder and gave it a band-aid fix of using Mercon V (actually a synthetic blend formula, not pure). When done properly it wasn't an issue but if the fluid was mixed it lead to all sorts of problems. The proper way was to drain not only the pan, but the torque converter as well. This step was often overlooked by professional techs as well as backyard mechanics. This lead to seal failure and eventually transmission destruction.

I'd recommend asking in a model/manufacture specific forum about using newer fluids in older cars. It might prevent an expensive lesson.

If it's a high-quality synthetic like Amsoil ATF I'd not hesitate to use it. That ATF will work with many applications. If the transmission specs some form of Dexron or Honda Z-1 ATF the Amsoil will work well.

if it is the 1986 under your nick, keep some oil filters handy. Synthetic likes to remove gums, it is normal.

the more crud the quicker it fillsthem, heavy filters are not a bad sign, it means it is working. Good choice, syntheic, for most brands anyway. :thumbup:

good tips. i'll watch out...
i can wait until 3000 miles,either way, right?

As long as you check your oil frequently for awhile.

Your first synthetic change should be at or near 3k, the rest of them can be longer, if you're comfortable with extended oil changes.

I wish I'd taken a pic, but I ran the same oil/filter in Cara for 10k+ miles and only added 2qts, one to replace the MMO as it burned out, and one at 5k miles. After all that time with 0w30 oil, the engine oil was still clean and honey-colored, not black. I wasn't running an air filter for most of that, either.

I've heard lots of stories about synthetic oils doing harm to engines and transmissions, and after further looking into each claim, I've always found that it came down to user error. Most people think they know things, and don't ever bother to read directions, and that causes problems.

I don't care if I've done something 100 times on 100 vehicles, if I get a new vehicle, or anything changes, I read the directions. There's a good reason for it, and I have a track record of NOT screwing up as a result.

hey, uh, do i have to worry about the tranny filter getting filled/plugged?
my tranny filter is inside the tranny.. unaccessible. lol.

Should have changed the filter at the same time as the fluid, really.

If your transmission starts acting funny, drop the pan, run the fluid through a strainer/filter (T-shirt in a collander) and you can reuse it with a new filter, as long as it's still pinkish red. If it's discolored, or has a burnt smell, discard and install new fluid. This time, check to see if your torque converter has a drain plug.

i get that. the reason it wasn't done was, i wan't going to go through all that, nor pay someone. i went to a "penzoil oil change" oil change company to flush and add tranny fluid.
their tranny flush does not drop the tranny and claimed to back flush the tranny filter.

so my question should have been:

what are the odds i'll have trouble?
i replaced 25yr old tranny fluid in a tranny that's never been dropped.

My answer is:

Have you ever tried to wash grease out of a t-shirt from the backside?

That's what they just did. If they flushed your transmission, there is a high likelihood that you'll have trouble in the near future. Monitor your fluid closely for grit and a burnt smell, and pay close attention to your transmission's cold and normal operating performance.

If you see grit in your fluid, there's a good chance that the clutches are wearing in your transmission, and it may fail as a result. Most OEM's do not recommend transmission flushing due to this sort of thing. Also, as I noted above with the T-shirt analogy, it's simply not possible to clean a filter by back flushing it. You'll get the solid particulate off the surface, but the filter media will still be dirty and restrictive, which is bad.

i;ll watch. i knew i was prolly taking a gamble, but i;ll keep ya posted on effects.

I'm not going to guarantee a doomsday scenario for you, because it doesn't always happen. Better to know what could happen and watch for it, though.

had a flush done on my 2001 f250 ,waited way too long,130k,, jiffy lube made me sign a paper holding them harmless if the flush damaged my trans,so sounds like flushes dont always end so well like christ said,but knock on wood 160k now and it survived.

mmm k, so far:
i pushed my weekly commute at 72mph @ 3mpg increase (11.5%).
i;ll be busy driving a lot this week, but on thursday night i;ll hypermile my regular commute which i do track closely each direction for it's increase.

Invest in some Auto-RX and put that in yer transmission. Hopefully any crud in yer transmission will git dissolved before it becomes a serious issue. ;)

This is an old writeup I did after flushing an auto in an '86 Nissan V6.....

I did several flushes over say 10K miles using regular ATF and each time checked the fluid coming out in a clear jar...I could see floating "gum" particles. After about the 3rd flush I put the synth in along with the Lubegard additive...which is what finally helped a sticking valve in the trans.

You can find the Lubegard add at NAPA...but you need to use the exact type called for for your car.

......

My experience (which is limited) is that when you change or flush an auto, you remove the buildup of clutch grit and metal particles (which are wearing your trans out), but you also put in new ATF which starts to pull the varnish and gum out off of the interior surfaces, valves, etc...and with the grit gone, you can have more slipping.

Best bet is to totally flush the trans thru the hoses at the rad...this way you can remove almost all the ATF from it and replace it with new...instead of about 1/2 of it thru the pan.

You would probably want to start with regular ATF and do a full flush 2-3 times lasting about 1000 miles of drivng each....in order to clean out most old sludge, grit, and varnish......and then put in Mobil 1 synth ATF.

Mobil 1 synth usually helps a trans to have crisp shifts, if it's not loaded down with crud.

The vacuum modulator valve also controls shifting in a major way and my limited experience says it would be best to use a used OEM vac modulator rather than a new aftermarket one. New OEM is even better.

How to do it: Check that the trans is at a FULL level first.

If you've removed or drained the pan, you've probably removed about 1/2 the ATF already & cleaned the pan & replaced the screen or filter.

With the front of the car on ramps....find the hose at the radiator that comes from the trans (one that flows to the radiator), put the radiator end in a bucket...& with a hot trans...run the car at IDLE in PARK till the flow almost stops...then shut it off.

Add the same amount as you took out. Do this until you see clean new ATF coming out. If you have a clear container you can compare old & new ATF.

Put the hoses back on securely and check your ATF level. Drive for 1K miles.

* Need to be very careful when removing the old hose from the radiator...or you might end up replacing the rad. You also might want to replace the old hoses if they are hardened...but use ONLY the right hose type though. With new clamps.

Later, if you do the flush a couple of times without removing the pan...you will need to exchange all of it.

If the pan gasket did not leak, and it comes off with the gasket intact...just bolt it back on to specs...do not overtighten the bolts.

This flushing method is easier on the trans than the commercial methods, since it uses the regular working of the trans to do it. Keep things very clean...no lint from a rag even.

I also use Lubegard trans additive which can help with sticking valves and governors that synth ATF might not help...you need to buy the right kind for a Honda though.

Redirecting...

Also sell a flushing additive....

I do a total flush about every 15K miles with Mobil synth ATF after cleaning the pan. And add more Lubegard.

Another method is to drain the trans pan at each motor oil change and refill, replacing about 1/2 of it. This would be done after the flushing process was done.

Some trans have bands/clutches that can be adjusted, but if it works reasonably OK...I'd say, just flush it and don't mess.

* no guarantees....this process may or may not work as expected....all transmissions are different....so are the people working on them....

thanks.
i may be too lazy for all that. what if i just get a regualar trans flush every 3k miles with my oil change 2 or 3 times? lol.

The cooler line flush can be done by 1 person, although a second person helps. I put an empty milk jug where I could see the top, ran the cooler line extension to it, hopped into the drivers seat, and cranked the car until the jug was full. The size container to use depends on your transmission's capacity. Some Honda transmissions take about 5-6 quarts of ATF while my Buick takes 14. So 4 quarts low wasn't too big a deal for me.

For your car I'd pump out the pan several times over the next few thousand miles, assuming you have a dipstick to check ATF level with. This will get the gum and varnish out and new fluid in.

You mean a drain and fill? If you have someone do it...it will git pricey pretty quick and it may not improve the condition of the transmission at all. In most cases, you need to head off what ever crud is built up in the older transmission and git that taken care of as soon as possible. It would be like only draining 1 quart of yer motor oil out and filling it with a quart of new oil and expecting it to last another 3000 miles... :(

Best thing to do is just do it the right way the first time. :D

The easy way would be to just drain and refill...replacing about 1/2 the fluid say 2Xs per year. But you should drop the pan...clean it and replace the filter. All the grit and metal particles will be in the pan...and some trans have actual filters instead of screens. You'd need a Haynes manual to do it right.

Might also stick a neo magnet on the bottom of the pan to help catch some steel?

When I did my Nissan...I'm fairly sure it was the original oil in it...it was brownish instead of red. If you tested it vs new ATF between thumb and forefinger...you could tell it had less lubricity....no slicky...slicky.

When I put the new engine in my wife's car, I pulled the trans pan and cleaned out as much of the old fluid (drained torque converter) as I could at the same time. Inside the pan, was a magnet, which had a very interesting rippled pattern of nearly fluid particles of ferrous metals. Very thin layer, maybe a 1x1" square, but very definitely noticeable. I cleaned it off, shined up the pan, cleaned the gasket, installed the new filter, and refilled the trans with close to the spec through the fill plug (no dipstick), then ran it to warm it up and did the check through the fluid inspection hole on the side of the tranny... took another 2qts past "spec" fill to actually get it full to where it was supposed to be.