fluid change

[oltrsty]

i am going to change the fluid in my 1984 gmc sierra classic 2500. It has a th 400 transmission. How many quarts of fluid do I need for this job?

 

[Grit dog]

Short answer is it depends how you’re doing it. Based on the overly simple question, may want to look into it and what you’re trying to accomplish with the fluid change.

 

[Finkaire]

More or less 4 quarts. My pan was distorted so I replaced it, fairly inexpensive.
Also a good time to add a drain plug, no way out of making a mess!

 

[Edelbrock]

Google:

AI Overview

Changing transmission fluid generally doesn't damage the transmission, but it can exacerbate existing issues or cause problems if done improperly or on a vehicle with high mileage and a poor service history. Replacing old fluid can loosen accumulated debris, potentially leading to short-term performance issues or even failure in some cases.


Here's a more detailed explanation:

• When it can be problematic:
  • High mileage vehicles with no service history: If the fluid has never been changed and is severely degraded, changing it can release debris that clogs filters or valve bodies, causing transmission issues.
  • When it's generally safe:
    • • Regularly changed fluid: If the fluid is changed at the recommended intervals, it's unlikely to cause problems.
        

 

[Turbo4whl]

When you remove the trans pan and filter, you only change about half the fluid. The converter and shift pistons hold the rest.

MOST IMPORTANT, use the correct trans fluid. The parts house may want to sell Dex-Merc. How can one fluid be good for 3 GM and 4 Ford types? It can't. Your trans needs Dexron III. Dexron VI is the replacement now, for Dexron III.

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[Turbo4whl]

Google:

AI Overview

Changing transmission fluid generally doesn't damage the transmission, but it can exacerbate existing issues or cause problems if done improperly or on a vehicle with high mileage and a poor service history. Replacing old fluid can loosen accumulated debris, potentially leading to short-term performance issues or even failure in some cases.


Here's a more detailed explanation:

• When it can be problematic:
  • High mileage vehicles with no service history: If the fluid has never been changed and is severely degraded, changing it can release debris that clogs filters or valve bodies, causing transmission issues.
  • When it's generally safe:
    • • Regularly changed fluid: If the fluid is changed at the recommended intervals, it's unlikely to cause problems.

Yes, this is what happens when you mix in the wrong transmission fluid.