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Trans care for 1997 Chevrolet 3500

Diesel w/auto trans , 19,000 miles . What should watch /do to/for the transmition … Does it deteriorate over time ?? Any special fluid ??

Is this really a 21 year old truck with 19,000 miles? Or is it 190,000 miles?

I’m imagining an automatic transmission, so quite possibly a 4L-80E

If so, Dexron 3 is the correct fluid

used as a squad truck by local Fire dept W/ a covered utility body on it . I’m wondering what kind of wear and tear takes place while just sitting ??
---- Mustangman wrote:

Sitting doing what? Being parked? Or idling? And again, does it have 19,000 miles or 190,000 miles?

Even with 19,000 miles, it may have 5000 hours idling. It may have 10,000 hours. 100,000 road miles is about 3500 hours, just for reference.

Whether it has a lot of idling time or not, I’d give the same advice. Just do a transmission service. Drop the pan, change the fluid and filter. There’s really not much else you can do.

I’d imagine seals in the transmission could’ve dried out over that 20 some odd years sitting. But no more or less than the rest of the seals and rubber parts on the rest of the truck.

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Thanks for that inspirational message . The truck has been used by a volunteer fire dept in a small fire district , I don’t think it has ever gone very far . Thanks
---- Scrapyard_John wrote:

It’s a real 19,000 , I never thought about it with that type of reference , being a fire dept squad truck it may have many idling hrs on it .thank you
---- Mustangman wrote:

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Automatic transmissions require really high fluid pressure passages to develop enough force to change the gears, so it is critical the seals remain in good form. Transmission fluid contains seal-conditioning chemicals for this, so the post above suggesting to do a simple transmission service is good advice. The seal conditioning chemicals will then be new. Avoid a transmission flush procedure unless it includes dropping and cleaning the pan and replacing the filter.

Didn’t mean to sound…non inspiring. I just meant that there’s not much you can do proactively to an auto trans other than new fluid and a filter. You could change the filter and then exchange all of the fluid (rather than the 5-6 quarts you’ll be changing with a pan drop), if you wanted to go all out.

As far as the seals comment, George stated it more eloquently when he said the conditioners in the new fluid will help with the seals drying out.

Thank you for your input , when I take possession I’m planning to bring it up slowly to everyday use , no short rides and no - out of town rides till I build confidence in myself and the truck .
---- Scrapyard_John wrote:

Thank you !!
---- GeorgeSanJose wrote:

With all the idling the transmission is probably pretty well lubricated, because when the engine is running the fluid must have been circulating some, keeping things warm and slippery. If the truck had occasional servicing, like an annual oil change and look-over, it’s probably in good shape. The volunteer fire department where I used to live kept up with that sort of thing.

Unknown how much it idled. If it wasn’t at a fire, it probably just sat.

From a former wildland firefighter.