What is the transmission dipstick length?

TWEBB101

MEMBER
1984 CHEVROLET TRUCK
7.4L
V8
2WD
AUTOMATIC
169,900 MILES

I'm trying to determine the correct length of dipstick I need for my transmission fluid level. The engine is a 454 and the transmission is a THM400 3-speed. The stick I have now is 32" long, not including the handle. I tried to look online but got varying answers with varying lengths. Can you help confirm the correct one?

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

I believe the filler tube is approximately 25" in length. The dipstick would be a few inches longer.

Since GM no longer produces this part, you can get an aftermarket. Even if the filler tube is a bit shorter or longer, the manufacturer has compensated for that in the dipstick. Since we can't be sure about what you have, I would recommend replacing the tube and dipstick together.

I know Mr Gasket makes one for this truck. Here is the part number: 9765A 9765

Check that out and let me know if it helps.

Take care,

Joe

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Wednesday, November 9th, 2022 AT 5:59 PM

TWEBB101

MEMBER
178 POSTS

Thanks! Can you also tell me the amount of fluid needed for a transmission fluid change?

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Thursday, November 10th, 2022 AT 12:31 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Interestingly, the manual doesn't have the specifications for a service. I know it holds 11 quarts of it is totally dry, but that isn't the case when you drain it.

Here is what I suggest. Start by placing approximately four quarts to start. Once you add the fluid, follow the directions I attached below. Also, it doesn't mention it, but I would shift it through the gears before checking the level.

Let me know if this helps.

Take care,

Joe

See pic below.

Image (Click to make bigger)