Transmission Oil Unchangeable Over 100K Miles?

[hunter_he]

Hi everyone,

I found my car did not shift quite smooth in low speed so that I decided to change the transmission oil. Mine is a 1999 LS400 with 138k miles.

Today I called the Lexus dealership and asked whether I can change transmission oil there. However, the person there told me that normally the car can change transmission oil for 100k miles but there was a risk of destroying transmission when the car was with such a high mileage. Therefore she did not want suggest me change the transmission oil. I just get confused that what potential damage to the transmission when changing oil.Also, what else I can do to make the transmission smoother under low speed.

By the way, between 03'-04' GX470 and 04'-05' Land Cruiser, which one is better to consider?

Thanks.

[landar]

Has the transmission fluid ever been changed on this car?

[hunter_he]

It was changed at 114k miles.

[pachanga]

Mt .02 cents worth as to changing the transmission fluid. I purchased a 1994 LS400 this past June with a questionable history - no records, etc. for a very good low price. It had a 135K miles on it and basically needed a lot of TLC. Best part was the interior was in excellent shape. In the month after the purchase - I changed the engine oil and filter and I followed a procedure here on LOC forum to change the transmission fluid and filter. I dropped the pan, changed the filter and reinstalled the pan. I then located the return line from the transmission cooler going back to the transmission. I purchased from the local Lexus dealer parts depart. a case of the Type 4 transmission fluid for a cost of $80. I ran the hose that was attached to the transmission line to a five gallon bucket .. my wife would crank the car - I then monitored how much transmission fluid came out - when three quarts were pumped out - Turned engine off, and then put 3 quarts of new transmission fluid in. We did this cycle until the fluid coming out turned from a brownish color to the nice pinkish red color of the new fluid. that was approximately 10 quarts. Just to make sure - I let another quart come out and then re-attached the transmission line to the return line to the transmission. At that point, I only had to add one quart more transmission fluid for the mid-mark on the transmission dipstick to be reached. Checked all connections, pan bolts and called it it "done". Now - I like to think I could tell a difference in the drivability of the car.. well... not really. It shifted fine before I changed the fluid - however I feel better knowing that there is fresh transmission fluid in the transmission. And 5000 miles alter - no issues, no problems, engine and transmission are operating smoothly and very nicely. It went so well - we changed the transmission fluid in my wife's 1998 LS400 (178K miles) the same way. No problems have risen with changing the transmission filter and fluid in the 2000 miles she has driven it. Cost was approximately $120 bucks for each car - fluid, filter, gasket.

And I also got samples (a quart at a time) as the fluid came out of the line to put in glass jars to set aside for a week to let any metals, brass, steel, dirt, etc settle to the bottom to see if there were large amount of metal or other sunstances in the fluid. The 1994 had some dark particles - maybe steel but .. not much at all .. and the 1998 LS400 was very clean... just a darker color there.

[landar]

The big question is whether the fluid was completely changed at 114k or whether it was just the quick, two quart change. You could do the complete change that Freddie mentions above. In any case, I would start by pulling the dipstick and seeing what color the fluid is. If it is darker brown then you will probably immediately benefit from a fluid change. But it the tranny fluid truly was completely changed at 114k then I do not think you will benefit. That was only 24k miles ago.

Your dealer is being a bit overly dramatic, IMO. Sure, if the fluid had never been changed, a flush *could* loosen some built-up crud in there and clog the inner parts. I think it well worth that small risk to change it if it is old You will have to check to be sure. It will not hurt anything to completely change the fluid with fresh other than hurting your wallet.

[Exhaustgases]

Both engine oil and automatic transmission fluid have certain additives that deplete over time. A person could use that same theory with engine oil as the person at the dealership used for the transmission. A slow change of the trans fluid should not hurt a thing. As it is helping to reintroduce those additives that are degraded. Rather than a full attempted flush like described above, just do the normal drop the pan at first then just drain on the next engine oil change. Depending on how often engine oil is changed just do the same for the trans. What is it about 2 quarts or so.

[billydpowell]

I agree with Egas (Both engine oil and automatic transmission fluid have certain additives that deplete over time.) and also agree with the way (2qt) with oil change method of change....

[RA40]

As egas and Billy stated. The DIY 2 qt incremental drain is a common means to gradually exchange the old fluid out and with very good success rates. In worst cases, dropping the pan and cleaning the shift solenoids. If the car is still shifting the fluid exchange usually takes care of it. The fresh fluid has detergents that clean so if the fluid is more on the blackish side, the 2 quarts gradually introduces itself. A full fluid exchange is fine on trannies that have received regular fluid changes as the accumulation of particulates and residues are far lower than a neglected tranny.

For DIY, Type IV from the Toyota dealer is sub $5 but may be as high as $7. Also get the metal crush washer, these are single use only and cost about $1 but I've seen them as high as $3.50.

What comes out goes back in so measure carefully. The tranny performs nicer with the fluid at proper levels. To much or to little can have shifting issues but are easily remedied.