What is the transmission dipstick length?

Tiny
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?
Wednesday, November 9th, 2022 AT 12:13 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 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
Tiny
TWEBB101
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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
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 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.
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Thursday, November 10th, 2022 AT 7:37 PM

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