changed my transmission fluid today

[peppster66]

Wow, that was long overdue.did it myself in the driveway, changed the filter and used mopar plus tranny fluid,I was really surprised by the small amount of sludge in the pan, also there was a tiny amount of metal shavings stuck to the magnet in the bottom of the pan.it was a fair amount of work, but will be well worth it in the long run., after refilling the fluid, I let it warm up a bit and slowly shift through all the gears. Checked the fluid level one more time, then took it out for a test drive, I knew it would be better, but I was really amazed at how much smoother it shifted, and how much quieter it seemed to shift. I would highly reccomend to change your tranny fluid if you havent done it in a while, I really think it will help the transmission last much longer,,,,, take care,,,,.Josef,,,,,

[mkguitar]

suggest that anyone doing this consider a swap to a pan with a drain plug- most US vehicles do not have a drain plug.
speed shops will carry pans by Milodon or others- some may have increased capacity and a longer mount for the filter/pickup.
( for like $100- they are cheap)

a cheap easy drain and fill can be done by the owner siphoning out the old stuff though the dipstick tube ( many jiffy places do this)- this is incomplete but will refresh the fluid.

even so, a large volume of old fluid remains in the torque converter and teh cooler lines..so even for Peppster he has replaced maybe 2/3 of the fluid.

certainly better than nothing- good for the seals and O rings and will help clean out varnished oil

Mike

[peppster66]

Mike, you are right on that one, it would have been much cleaner and easier of a job if there was a drain plug on the pan, I thought of adding one while I had the pan off, but my welding skills aren't that good yet, there are some screw on kits you can buy on amzon, or at auto supply shops,but I was too afraid of leaks. I always found it strange that they never had the plug installed as original equiptment.some people call it a design flaw, if I do it again , I will plan to add a plug to my pan,,,,,,

[booster]

Originally Posted by peppster66

Mike, you are right on that one, it would have been much cleaner and easier of a job if there was a drain plug on the pan, I thought of adding one while I had the pan off, but my welding skills aren't that good yet, there are some screw on kits you can buy on amzon, or at auto supply shops,but I was too afraid of leaks. I always found it strange that they never had the plug installed as original equiptment.some people call it a design flaw, if I do it again , I will plan to add a plug to my pan,,,,,,

I usually get the purchased bolt in drains because they are easy to find, but when I install them, I leave out any gasket and silver braze it in. It works well that way as you can tighten down the nut to hole it in place well, and the silver braze will insure it never comes out or leaks. Welding can distort the pan a bunch, and if you want leak free, you really need to use the Tig, which most folks don't have. I have done dozens of pans for folks.

[markopolo]

My GMC has the drain plug on the pan. It takes a Torx T-55 bit.

I get around 4.75 qts to drain out of the 4L80-E trans through the drain. It takes 7.6 qts if you drop the pan. A complete overhaul takes around 13.5 qts according to the shop book. I drained it 3 times in one month and figure it might have been 75% new fluid in there then. Just a guess though.

The hardest part is getting the fluid level right. I find it very hard to see on the stick (my vision is good).

Instructions for checking trans fluid level in my van:

1. Start the engine and operate the vehicle for 15 minutes or until the transmission fluid reaches an operating temperature of 82-93°C (180-200°F).
2. Park the vehicle on a level surface.
3. With your foot on the brake, move the shift lever through each gear range. Pause for about three seconds in each range, ending in Park.
4. Apply the parking brake and let the engine idle for three minutes.
5. Remove the transmission fluid level indicator. Wipe the indicator clean. Insert the indicator. Give the indicator a full twist in order to close.
6. Wait three seconds and remove the indicator.
7. Read both sides of the indicator. The proper fluid level should be in the middle of the X-hatch.

[booster]

The infamous fluid level check in the Chevy van. We had quite a discussion about that a while ago with some interesting methods of making it easier to do, including overnight sitting IIRC. I don't remember what thread it was in though.

[peteco]

Marko,

Search the web for instructions on where to remove a transmission line from the radiator cooler and let the transmission pump the old fluid out. That way you get a full flush.

I start by draining from the pan, and removing the pan to change filter and clean the pan. Then reinstall the pan and add the amount lost during the pan drain and drop.

Then disconnect the appropriate fluid line, attach a hose to pump into a marked gallon jug, and start the engine. Pump out about a quart or 2 into the jug and stop the engine. Be careful because it pumps out pretty quick. Then add new fluid for the 1-2 quarts pumped out. Repeat process until fluid being pumped out is new fluid. This is actually easier than getting under and removing the plug several times, and gives a much more complete flush.

[markopolo]

Thanks for the tip - I'll check it out.

[booster]

The whole tranny fluid change thing has a lot of variations in how, and how often, it is done. The old standard has always been drop the pan, change as much fluid as you can, the filter every time, and be done. Some of the older stuff actually had torque converter drain plugs in them too, but haven't seen one in quite a while. Now, at a lot of places, the method of choice is the full fluid change, "feed and bleed" setup. This changes all the fluid, but not the filter. There are variations of both ways like Peteco's or the drain in the pan no filter change.

I took an auto transmission rebuild/service class about 25+ years ago at the local votech, and there were some very interesting discussions about all the methods, particularly the full flush machines. The instructor was really good and knowledgeable. He regularly was invited to all the manufacturer training sessions, so was up on it all.

The takeaways from the class and discussions were not what I expected them to be.

* He liked the flushing machines under the right conditions. The recommendation was to never use the flushing machine on a transmission that had very dirty fluid in it, which was exactly what the shops were pushing it for at the time. All the clean fluid into a very dirty transmission would put too much detergent into the system, risking dislodgement of debris that would destroy the transmission. If you had a transmission with a screen filter (they are up out of the fluid at the valve body area in most cases), and changed the fluid often so it wasn't flithy, he thought the full flush was very good. Along the same lines, if you do the pump out with the transmission itself, you have to be certain that it always has enough fluid to not suck air, as the cavitation can also shock loose debris. Clean transmissions don't have much issue though unless the run too dry.

* He was fine with the drop the pan method as long as you are careful about dirt getting into things, which apparently is/was a lot more common than I realized as I tend to be very careful about it. The other warning was to never use silicone sealer on the pan, as any ooze out will not cure in the fluid and gum up the valving. His recommendation was to always change the filter if it was the fabric in the pan, and that the high mounted screen rarely if ever needed changing. It was interesting that he would not recommend ever this much fluid change for a high mileage 125K+ trans that looked very dirty for the previous reasons.

* He was OK with a drain in the pan to get easier changes. If you have one with a fabric in the pan filter he thought every 3-4th fluid change would be OK for the filter, as long as the fluid changes were fairly short (20K is what he liked, double that if totally flushed). No need to remove the pan on the screen filter units. Of course harsh use would modify the intervals.

As it all worked out, I think he had called most of it spot on. As the flush machines got to be more common, there were a bunch of articles and studies done about them causing failures, and recommending less severe means for the dirty and high mileage applications.

There is also one other thing that the flush machines, and regular style changes also, can get into, and that is what transmission fluid is used to replace the old. Back in the day, you used TypeF or Dexron for most everything, and they were pretty compatible with just stick/slip characteristic differences. Folks used to mix them all the time at the dragstrip (and on the street) to modify the shift quality. Now nearly every manufacturer has their own very specific fluid. It all started for the most part, when Chrysler went to ATF4 (? I think) to stop the failure issues they were having in the minivans. The new fluids seem to be very carefully matched to transmission design, very thin for economy, and mostly synthetic now.

The uneasiness comes in that many shops use universal fluid in all the vehicles, unless you specifically insist they don't (and then some still use the universal I have heard). Hondas seem to be very susceptible to not liking non Honda fluid for some reason, but I think these days it is worth the extra cost to go with the manufacture spec fluid for all vehicles. It doesn't have to be their brand, just meet the spec, like Valvoline Dexron VI does for GM. Valvoline one size fits all isn't specific.

This all gets very controversial, and sometimes downright ugly, when you throw the in the high end, aftermarket, synthetics, like Amsoil, Royal Purple, Redline, etc. As far as I know, none of them have the specific manufacturer spec ratings, so really are universal fluids. When you look up the data, they will say some careful wording like "designed to be used in vehicles that use the following specifications" not that they meet the specifications or have been tested to the spec. I have no data on how good or bad they would be in any specific transmission, but I find it highly unlikely they could have the right viscosity, viscosity index, detergent, and stick/slip to match all of the transmissions they say to use them in. Your opinion may differ. I am not anti aftermarket stuff, or Amsoil or other brands, as I use almost all the brands in different areas. Just not in auto transmissions.

I have only the small sample anecdotal personal experience in actual results, so I didn't list them above, and have no idea if they are indicative of anything useful or not.

* Brother in law lost the trans in his Taurus at about 10K miles after switching it to Amsoil with a complete flush from a flushing machine. It had about 100K on.

* DW's 2009 Honda CRV was built right at the time Honda was switching to synthetic on their specific trans fluid, and the supply of fluid had been delayed somehow, per the dealer. Add to that it was a first off for the model year, so it was built in Japan while Ohio was in model change and to prove out changes. We were surprised as it shifted harsher than we expected and asked at the dealer what was up with that compared to past Hondas. They felt that the transmissions had been recalibrated to the new fluid, but the fluid wasn't yet available when some of the vehicles were built (I doubt he came up with this without help from Honda, as it was immediate when I asked). Once the new fluid became available, I changed the fluid several times in a couple days (it has a drain plug) to remove as much out as possible, and shifting went right what we expected it to be.

I will be changing the fluid in our Chevy about every 20k, and from what I have seen, it stays very clean to that point, with just a light fade of the red color. The Chevy still uses the pad filter, so I will probably do that every 3rd time. It is great that ours has the reusable pan gasket on it, so no sealers and stuff to deal with.

Last hint-if you are draining with a plug or pan off. If you let it sit overnight, you can usually get more fluid out as the pump and maybe converter do leak back for a long time. Every trans different in how much more you get. If you do it with the pan off, be sure you are in a very clean area, or temporarily put the pan back on with a couple of the bolts.

[peteco]

Originally Posted by booster

I will be changing the fluid in our Chevy about every 20k, and from what I have seen, it stays very clean to that point, with just a light fade of the red color. The Chevy still uses the pad filter, so I will probably do that every 3rd time. It is great that ours has the reusable pan gasket on it, so no sealers and stuff to deal with.

Just curious, why every 20k? I change at 50k but maybe 20k is better due to the heavy load on vehicle.

Do you just do a drain and fill, or a full exchange which can take about 15 qts to get clean fluid being pumped out?

[booster]

I do just the drain plug thing, and get in the range of 1/2 the fluid if it sits a while. It is the same effect on average to go at 20K compared to 40K for a full flush, so we aren't that much different. I will say that the Chevy seems to be pretty easy on the fluid compared to some of the cars we have had, so it is probably more often the really needed, but in the big picture, fluid is cheap and trannies are expensive, as they say. I also don't know which method would be best for the transmission. If the fluid isn't visibly dirty at that point, it would probably be more do to additive depletion or viscosity shear down and who knows. I do think if I ever saw the fluid over 220/230 degrees on a trip, I would change it when I got home.

I do know that I hate those Chevy transmission line clips ever since I added the tranny cooler. One disappeared like a rocket when I was taking them off. $8 at the dealer for tiny hunk of wire

[peteco]

Originally Posted by booster

I do know that I hate those Chevy transmission line clips ever since I added the tranny cooler. One disappeared like a rocket when I was taking them off. $8 at the dealer for tiny hunk of wire

When I removed mine I saw the potential for that so I got a couple of spares at Advance Auto just in case it happens.

[Bruceper]

Don't forget the filter, which cannot be changed without removing the pan.