I've been meaning to ask this question for some time, but I've had so many other little projects going on I forgot.

But anyways, a couple of months ago I was in the city, and for convenience sake, I stopped in at a transmission "specialist" shop to see about having my trany (C6) serviced. I was thinking having it drained and have filters and whatever consists of a full service done, as I don't think this has ever been done for this trany, and the guy there told me he didn't recommend that as it isn't a good idea to "stir things up" in an older transmission.

Isn't that the idea though? Stir things up, get it out, and start fresh? Has anyone here ever heard of something like that? Seems kinda "off" to me...

Ideas?

 

I have heard that before, but I would ignore that advice. They claim the new oil will cut loose deposits in the tranny and clog things up.

But I have serviced trannies with a lot of miles on them, and I knew I was the first one in there because of the little "plug" rolling around in the pan. These trannies always shifted better with the new oil in them and never gave me any problems.

 

Yea, that's exactly what he said. That seems to be a "word of wisdom" from these guys then, if you've heard the same.

That begs the question then, where does this idea come from? If it was from just one homer at one shop, then ok, but you've heard that also.

I plan to go ahead with a service of my trany, just because it sounds like a good idea. What would a back yard service consist of?

 

I've heard this for years, the theory being that if you get rid of the debris in the fluid that is providing friction in the clutches they start to slip. I've always thought that if that were the case then the trans was about ready to let go anyway. I consider it a an old wives tail.

 

That recommendation isn't limited to only trans either. I've heard people use it with just about anything that involves changing fluid... differentials, radiators, etc. I would ignore it.

 

It's based on the new wine in an old skin proverb. I've seen it go both ways. I've seen people change the fluid in an old transmission with no problems whatsoever, and I've seen the transmission suddenly develop slipping issues. Any way you look at it, if you don't drain the torque converter too, you are going to be mixing old fluid with new fluid. I would think that all old or all new would be best, but that's just my opinion.

 

It would be rather hard to clog up the filter in a C6. It's just a screen, to keep out the bigger stuff.
Newer transmissions can have issues after being flushed, as the flushing stirs up the chunks that have settled at the bottom of the pan safely out of the way. The C6 rarely needs more than dropping the pan and cleaning it out good, filter replaced, and convertor drained before putting it back together, followed by refilling with fluid. They usually work much better after having this done.
Only time I have ever seen a C6 that died after having been serviced, was one that had been neglected far too long and was already having issues. The service was done in hope of reviving it.
If it works good, chances are a service will only extend it's life, rather than shorten it.

 

Wait, are you having the trans rebuilt or just doing a filter service? If you're having the trans rebuilt it'll have fresh fluid. If you're just doing a filter service, save the effort of taking it somewhere and do it yourself. It takes around 30 min. to do and is easy.

To do it at home:

You may have enough room under your truck to not have to lift it up. The best tip I can give is to take the bolts off so that the pan tips down. So basically loosen (not remove, not almost out, just loosen) all the bolts on the pan. Then take off the first two rows of bolts closet to the engine and the last row closet the axle. Now go down the line and back off the bolts but in varying heights to allow the pan to tip. You may need to take a flat blade and carefully pry the lip of the pan to get it to tip after loosing the bolts up more. Let it drain till no more fluid is running out the pan. Now take the rest of the bolts out. I usually take the center bolts off last and when I do, I hold the pan up against the transmission. CAREFULLY pull the pan down and watch out for more transmission fluid (wear something you can stand to have ruined while doing this).

Drain the remaining fluid out of the drain pan. Take some brake clean and spray out the pan and wipe it clean. There may be a magnet in the bottom of the pan, pull it off and clean it, and return it back to the pan where you found it.

Crawl back under the truck to take the old filter out. If I'm remembering correctly, the C6 filter bolts in and there's a filter to vb gasket . When you take it off, just be warned that more fluid will shower down. Make sure the gasket area is clean and install the new filter. Don't ram the bolts on, the tq spec is probably around 45 or so INCH lbs.

Hopefully, the kit you get came with a rubber pan gasket (check before buying). Line the new gasket up on the pan. Take two bolts and put them through the pan and gasket (this makes it easier to hold the gasket in place). Install the pan. Tq specs are 8-12 ft. lbs for the pan bolts, so don't hammer on them.

Pull the dipstick out and pour 3-4 quarts of fluid in. Start the truck up and run it through the gears, P R N D 2 1 and then 1 2 D N R P. Probably a good time to peek under the truck to see if you have any leaks. Let the truck run for a few minutes and check the fluid level, add as needed. Take it for a quick spin around the block and then recheck the fluid level. Just remember to check your transmission fluid with the engine running and warmed up.


As for your other question, I was always taught that transmission flushes weren't good and that was from my tech school teachers. I think the biggest offender of this thought is the "power flush" type machines that force the fluid through the trans (running or not) vs. something like a T-Tech that uses the front pump of the trans to circulate the new fluid through. Personally, I'd just do the filter service and drain and fill. Then keep up with your trans services! Too many people neglect their transmission till they start having problems.

 

Just a fluid and filter service. I've done the simple service on Chevy transmissions before, but because I care about THIS truck, I was thinking I would do it right. So if I do like you outlined above, would you drain the torque converter also? I'm assuming there is a drain plug accessible behind the inspection plate? I guess I need to put the transmission in neutral in order to turn the converter around to get the plug on the bottom?

How much fluid would I need to get beforehand if I drain the converter? Are all transmission fluids created equal? Will it rain tomorrow? I guess that about covers all my questions....

 

I'll be honest with you, just leave it alone. If your converter does have a drain plug, the likelihood that it'll leak after draining it is pretty damn good.

 

No need to put the trans in nuetral, just turn the engine until one of the drain plugs is visible (there's usually 2 @ 180* seperation).
Draining the convertor and pan both usually requires 10-14 Qts of fluid to fully refill the trans. 2wd usually takes a couple qts less than a 4wd, as the pan is usually deeper on the 4wd.
As for the type of fluid, not 100% sure. Earlier ford auto's used type F, while some of the 80's and newer called for Dexron II. Both are getting harder to find. There should be fluid spec number or type stamped into the trans dipstick.

 

Your tranny in these years took Dexron II. If you want to do a complete job, I would turn the engine as mentioned and drain the converter. Turning the engine till you see the plug is the hardest part. As was said, you will need around 13 quarts when you drain the converter. The drain in the converter is a neat idea that isn't found on many vehicles. It lets you drain ALL of the fluid.

 

Theres a way you can flush it all out without messing around with the converter plug.


After doing your pan, fill it back up and find your trans. feed line going to the radiator or cooler. To find the feed line, disconnect both lines, start engine for a second, witch ever lines quirts out fluid is your feed line.

- Put a pretty big bucket under the vehicle and aim the feed line in the bucket.
- Prepare at least 10 OPEN quarts of ATF at your reach
- Put a good funnel on the dipstick tube
- Shoot abit of compressed air through the buttom of the rad or trans. cooler to send whatever crap and old left over fluid back to the tranny
- Start up the engine, and start pouring new fluid in, and don't stop. As much fluid will be comming out as you are putting in.
- When the trans. fluid comming out of the trans. and into the bucket is as nice and red as the new one your putting in, stop the engine.
- Reconnect the lines to the radiator or cooler, (make sure both are on)
- Restart engine and check level, add as needed.
- Go for a good drive, when you get back, re-check level, add if needed and your done.




It's best to be 2 people to do this job, one sitting in the drivers seat waiting for your command to start or shut down the engine.

 

I honestly think that advice comes from people who wait 160k to do anything to their trans and when it starts acting funny then they wanna change the filter and fluid

Would you wait till your engine knocked to change the oil?

I flush fluid the same way was above. On cars with no filter I fill it while pumping it out lol.

 

That's how i've been doing it on my motorhome for a couple years now. I flush it every end of season.

That's how I flushed it on my '89 F150 when I got it 6 months ago. When I took the pan off, it had that little plug in it still. I kepted it.

Did only have 57k miles on the truck when I got it.