Motor noise vs fan noise vs overdrive question

[SebasSF]

Ok, so it looks like I have one of the following based on oil pan shape: TH375C, TH400, TH475, 3L80, 3L80HD. My carb has one cable plus cruise, and a throttle position sensor, and a cable speedometer. I guess there is a label on the side, but it's blocked so I can't see it. I found a screw to adjust the idle speed...much better now!

[SebasSF]

I'm guessing 3L80HD...

[Andrew T]

Thanks for clearing that up, I always wondered why they never put a Lock up in the 475.

[SebasSF]

So I changed out my fan clutch today and went for a test drive...what a difference! Nice and quiet in all 3 gears. The job was a bit of a pain as the fan is encased in a shroud and you can only reach it through the doghouse. I removed the air filter, took out the four nuts holding the clutch to the motor with a wrench, then used a socket to take the fan bolts out. Slid the clutch out and reverse process. Hard on knees and back working over the motor. The old clutch was leaking fluid and clearly shot. Next purchase...Gear Vendors I think.

Thanks to everyone for the great information and advice... I'm really learning a lot!

[Andrew T]

For not much more than the cost of the gear vendors you can change to the 4 speed transmisison with the lock up torque convertor. This will cut 400 RPM more out of your engine speed at 65 MPH and you get a new transmission at the same time. I am not sure if one of the new 6 speeds would fit but that would be slick if it did.

Just something to consider.

Andrew T

[SebasSF]

I could replace the trans, bit it's fairly new. I also like the idea of a gear lower then 3rd but higher than 2nd for hose long highway hills. I did some crawling around yesterday, and found this Yellow info tag says Turbo Hydramatic FK 0131A, serial number 90 FKA 12348. I'm still not certain what I have...!