Automatic Transmission Fluid Change

[LJ11194]

So, I’ve heard more than a few times that if a transmission has gone with the fluid unchanged for a longer than average period, changing it can actually cause it to go out. Does this have a basis in truth, or is it just a rare coincidence? I’m sure I could’ve googled this, but I’d rather hear a definitive answer from the people here who have verifiable experience over what I’d undoubtedly find: Some guy on YahooAnswers who was in his friends car while the transmission went out or some such nonsense.

Topic

[EricTheCarGuy]

I actually made a video addressing this. I talk about it about about the 7min mark.

[LJ11194]

I’d seen that video but I must’ve forgotten what you said. After how many miles would you say it’s better to leave it be than risk damaging it by changing the fluid?

[EricTheCarGuy]

Can’t say really, it’s a hit or miss proposition once you go well past the recommended service interval.

[dreamer2355]

Its going to be a roll of a dice when it comes to servicing a high mileage trans with no service history.

[Alex]

I changed it on my del sol at 167k. It is running a lot better now, then again I do not really beat on my car too much.

[LJ11194]

My/my dad’s truck has had the fluid changed regularly for most of its’ life, but for the last year I do not know if it’s been changed at all, and that is a year of being driven 5-600 miles per week or more. I’ll see if I can find a record of the last change, but if it’s been 50,000 miles as it may have been, should I let it be?

[jim]

hi eric
only recently came across your site and think what you are doing here is simply great just a word on your trans overhaul i use to work at plant trans overhauls which are about 4 times bigger but the same construction and i remember you saying that the old trans discs you removed did not look in to bad a shape the best way to check a worn disc is put all the discs and plate from one pack and measure the overall thickness and then compare this to a new pack

[dreamer2355]

[quote=”LJ11194″ post=35219]My/my dad’s truck has had the fluid changed regularly for most of its’ life, but for the last year I do not know if it’s been changed at all, and that is a year of being driven 5-600 miles per week or more. I’ll see if I can find a record of the last change, but if it’s been 50,000 miles as it may have been, should I let it be?[/quote]

50k miles is usually at the right time for a trans fluid exchange. It should state in your owners manual on what mileage intervals to service your transmission 🙂

[LJ11194]

Well back in better economic times, this truck enjoyed being over-maintained. We’re talking a full fluid flush every 10,000 miles, with an oil change every 3,000. I credit its 255,000 miles to that. I’ll check the manual, thanks for all the help.

[EricTheCarGuy]

[quote=”jimbo” post=35266]hi eric
only recently came across your site and think what you are doing here is simply great just a word on your trans overhaul i use to work at plant trans overhauls which are about 4 times bigger but the same construction and i remember you saying that the old trans discs you removed did not look in to bad a shape the best way to check a worn disc is put all the discs and plate from one pack and measure the overall thickness and then compare this to a new pack[/quote]

Yea I’m aware of that but for the most part you can actually see a burned up clutch disc. There’s been a lot that’s happened since that video however as I’ve done a proper rebuild on it and found that it was actually the 3rd gear clutches that were damaged. I think it’s due to the upper plate being too thin. I’ll find out for sure the next time I’m in there. Thanks for your input.

[EricTheCarGuy]

Based on your description I’d change the fluid, I don’t think 50K is all that much, just last night I changed a Toyota trucks transmission fluid that hadn’t been changed in 150K. I think with your past service history you’ll be fine.

[LJ11194]

Thanks alot.

[Author]

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