oil and trans fluid

[kenny]

I have an 08 town and country with 106000 miles runs great and doesn’t use oil. i use high mileage 5 w 20 recomended. should I or should not use 1 quart of lucas? I’ve also heard you should never change fluid in an automatic transmission that it would clean it out to much. I dont know the past service on this van. can someone explain this for me? thanks by the way the oil i use is pennzoil

Topic

[Justin]

My rule of thumb is if the trans fluid hasn’t been serviced, depending on the condition of the fluid, smell etc…. Like say on a 100k plus vehicle usually you end up introducing contaminates or “knocking something loose” which can possibly cause problems down the road.

If you are going to drop the pan and replace the filter, I would probably say go ahead. Is it giving you any issues at the moment? Pennzoil is a quality oil and wouldn’t have any problems running it. I run castrol myself but mobil 1, pennzoil and castrol are all great oils.

[Douglas Haynes]

I tend to stay away from any kind of oil additive, but there are people who swear by them.

On the trans service thing there are lots of people who believe that if you change the fluid on a VERY old trans that has never had a fluid change you removes to much old clutch material from the system and the new fluid cleans everything to much and there can be bot leak and performance issues. The owner of the transmission shop I worked at years ago believed this to be true and would advise against fluid changes on high mileage vehicles that had never been serviced and did not have burnt fluid. He did, however, recommend regular fluid and filter changes in general.

Personally I am unsure about this logic but the guy I worked for was very good and a very honest shop and I have pretty much gone by his word. Unless I know the service history I do not change the fluid on an automatic unless the fluid is burned or insanely dirty.

[Andrew Phillips]

Save your money and skip the Lucas. Use the saved money to get the correct trans fluid. Your van needs ATF+4 or you will have trans problems down the line. I’ve never had a problem replacing old trans fluid in high mileage vehicles. I can understand the reasoning behind it, and it makes sense, but I’ve never actually observed that problem, not to say it can’t happen.

[Mike]

The advice about old transmission fluid makes a certain kind of sense, and well-meaning mechanics have passed the same info to me a time or two.

Personally, I tend to believe that it’s an old wive’s tale that gets handed down as gospel from grizzled mechanics to apprentices, and is probably a relic from the early days of automatic transmissions when fluids weren’t quite as magical as they are now.

[Justin]

Working in the field, I have done fluid exchanges with flush machines and changed filters when applicable or was sold with it also. And many being close to 100 or over with no issues at all also. So it just depends on the trans condition aswell. Sometimes a vehicle that has a prexisting issue cannot be fixed, and performing a flush or exchange heightens the issue.

For instance we had a 2009 Kia sorrento we had come back a week later after performing a service and it ended up getting a trans. Who knows if it was having issues before we serviced it lol. But I will say this, we do perform trans services on the regular at the gm dealer I work for with milage all over the board. Just some more info for thought.

I service my manual trans on my mustang every 15k regularly because I beat the snot out of it. My 2000 power stroke is going on 205k with no service work because I’m afraid of breaking something loose. I just hope and pray when the trans lets go I am close to home and not on the road with it.

[Author]

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