100K Mile Sealed Fluid AT'?

[VeryNoisyPoet]

Definitely consider changing the fluid before 100k. Up to a certain point it will work fine, but beyond that the fluid will no longer protect the transmission and the accumulated material suspended in it will begin to cause accelerated wear. When exactly that happens depends on transmission design, usage patterns, and the fluid itself. The factory fill on my mom's car was fried at 86k miles; shift flares and sloppy shifts when hot - fluid very dark brown with burnt smell along with high insolubles and wear metals in the UOA. My car had a partial change at least once in its life before I started doing maintenance on it miles but by 160k the fluid was fried and causing harsh shifting. Some vehicles will go 200k or more on original fluid- but when they do go bad, by then they are usually done for because of accumulated damage.

Clean fresh fluid is always better than dirty, sheared, and oxidized fluid. A few hours to do a drain and fill and maybe $40 worth of fluid could save thousands in transmission replacement in the future.

 

[Whimsey]

Originally Posted by VeryNoisyPoet


Clean fresh fluid is always better than dirty, sheared, and oxidized fluid. A few hours to do a drain and fill and maybe $40 worth of fluid could save thousands in transmission replacement in the future.


Agree, with the 6F35 in our Explorer I spend $20 for 4 quarts of Ford Mercon LV and and can do a drain and fill in less than 30 minutes taking my time. It's a lot cheaper than a replacement transmission if you intend on keeping the vehicle a long time.

Whimsey

 

[bunnspecial]

At least on the transmission that was in my Lincoln LS, I talked to the engineer who designed the thing advocated flushes every 30K miles despite it being a "lifetime" fill.

He insisted on flushes being preferable to drain and fill because on that ATF specifically and most ATFs in general, "draining" at most gets 50% of the fluid and usually a lot less. Flushing replaces ALL the fluid.

Despite a lot of folks being "afraid" of flushes, at least on that car(and presumably any other vehicle/transmission equipped with one) you would "tap" into the transmission at the cooler lines, and during the flushing process the transmission saw EXACTLY the same pressures as when it was in operation. The only real difference was that fluid that would normally go into the cooler was instead drained off and replaced by fresh fluid. This particular engineer in fact advocated flushes for all ATFs, and said that the only time a drain and fill was desireable was as part of a more in-depth transmission service that involved actually taking components of the transmission apart.

With that in mind, my ATFs get flushes. I stuck to his 30K interval on the LS transmission, although I stretch out newer units longer.

 

[ChrisD46]

*Looks like I can't use ramps to get underneath to check ATF level indicator right after draining ? If so , I would have to drain the ATF out cold then refill using the EXACT amount of cold ATF ?
Originally Posted by mclasser
My Elantra has the same transmission. I always prefer a dipstick but a D&F using the check/fill bolts doesn't seem too difficult on this unit.

 

[dubber09]

- Make sure fresh ATF is at same temp as one in the transmission.
- drain and refill with same volume, disconnect ATF cooler line with red paint mark to make the process faster
- attach clear hose to the tube you disconnected hose from and put it in a bucket, start car and drain about 1L of ATF into bucket, turn engine off, top up with same volume, repeat until draining ATF is close in color to fresh ATF
I'd suggest you have 1.5X as much fresh ATF as transmission's full volume before you start the process which means you need 3 gal of fresh ATF.
If you measure volumes taken out and going in carefully, you don't need to check level via side level hole.
Add about 30ml more than taken out.

 

[StevieC]

But this assumes that it had the right amount in it in the beginning and it could have been slightly under or over filled at the factory. It's the best if you don't have access to technical info for your vehicle on how to properly check it with the temperature/fill procedures.

 

[wdn]

I have the Gen 1 Tundra and that is the nice thing a real dipstick and a real filler tube. There is a sticker on it that says don't have to change it. I just had mine done with the newer T-IV fluid that is full synthetic. They exchange it through the transmission cooler so it might be a BG style transmission machine. I do like being able to look at fluid color and level on the dipstick and give it the sniff test though.

 

[KrisZ]

Originally Posted by StevieC
But this assumes that it had the right amount in it in the beginning and it could have been slightly under or over filled at the factory. It's the best if you don't have access to technical info for your vehicle on how to properly check it with the temperature/fill procedures.


While I can understand why a factory would underfill the transmissions, to save money, which I still highly doubt given that they promote lifetime fills, I have yet to hear any compelling evidence why a factory would overfill on such an expensive fluid. They have some of the most precise equipment available and given the production volume it would cost them a lot of money to overfill transmissions. In the industry that pinches pennies, I find it very unlikely.

Also, in case of VW where people claimed their transmissions were factory overfilled because the cheap plastic tool indicated so, many found VW revised the tool because it was underfilling the transmissions.

 

[StevieC]

I think it might be the person on the assembly line that might do so out of error or not caring.

 

[KrisZ]

Originally Posted by StevieC
I think it might be the person on the assembly line that might do so out of error or not caring.


I can tell you haven't been around a process that has been 6 sigma optimized. If a person is involved, all they have to do is insert the nozzle into the fill port and squeeze the trigger. The machine will measure the amount needed and stop. Sort of like torquing fasteners, you will not find a manual torque wrench on the assembly line. They have torquing equipment that only requires the operator to point and shoot.

The human factor is usually involved with processes that machines are not good at, like setting the final gaps between panels, routing wiring harnesses or hoses. Stuff like that, but not something as mundane and easily controlled by a machine as measuring fluid volume.

 

[dubber09]

Replacing with same volume will give you same volume, so if you don't change ATF and transmission is undefilled - it's still underfilled.
I do agree that checking level is the proper and best course action thou.

 

[KrisZ]

Originally Posted by dubber09
Replacing with same volume will give you same volume, so if you don't change ATF and transmission is undefilled - it's still underfilled.
I do agree that checking level is the proper and best course action thou.


The level checking procedure has an acceptable percentage of error, do you know what that percentage is? People stating that a transmission was underfilled or overfilled do it when compared to the fluid they drained vs what they had to put in by following the measurement procedure forgetting that the measurement process itself has a certain error factor. And as was the case with VW, the tool used was too short.

I'm not saying that one should not use the measuring procedure, but I would also not condemn the factory of an error because there is a discrepancy because the cause of the discrepancy may be the measuring procedure.

 

[wdn]

I agree with you. You need a dipstick to read the actual level and a filler tube to top it off as needed. With the flush and fill machine it relies on the calibration of the machine and human error by the operator. That error could be cumulative if you take it to the same place every 30,000 miles. They really need to exchange the fluid and then top it off as needed. Cars without a dipstick/filler tube have lost something. Even if you do a drain and refill yourself at home with an evacuator pump you still need to check.

Originally Posted by dubber09
Replacing with same volume will give you same volume, so if you don't change ATF and transmission is undefilled - it's still underfilled.
I do agree that checking level is the proper and best course action thou.

 

[StevieC]

I wouldn't sleep at night not checking it properly. Especially in expensive modern transmissions that can be fussy on absolute correct level.

 

[JeffKeryk]

The "sealed" transmission stuff just doesn't make sense to me. And 100K? Every time I service my old Tundra, friend's CVT, Acura, etc. it smooths out the transmission.
I will have Lexus service our GS350 with their WS; I will do it again with Idemitsu in a couple of months.

As far as "put back what you took out", that's a very good starting point.
It probably works, but learn to use the proper technique.