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Old 08-22-2023, 01:18 PM   #1
howzzzit
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Replacing TH350 bullet and driven gear question

If I drain the transmission pan first will I still get a gush of fluid when removing the bullet or is it just waiting for me in the housing?
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Old 08-22-2023, 02:18 PM   #2
geezer#99
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Re: Replacing TH350 bullet and driven gear question

I’ve swapped them out without draining anything.
No gushers.
If you’re unsure just lift the back of the truck or park downhill.
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Old 08-22-2023, 05:34 PM   #3
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Re: Replacing TH350 bullet and driven gear question

Start the truck and run it of 30 seconds before pulling the bullet. The running transmission fluid level is at the pan gasket line when the motor is running.
This will refill the converter if there has been any drain-back while setting.
Geezer#99 has given good advice. No need to drain the pan. May want to confirm the transmission isn't overfilled, using the level gauge before pulling the bullet.
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Old 08-22-2023, 06:24 PM   #4
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Re: Replacing TH350 bullet and driven gear question

Here's a glitch. The speedo cable will go back and forth about 1/8 inch each way, but won't unscrew. Ideas? Tried small channel lock . How about I take the bullet lock off and pry the bullet out with the slot and then try to unscrew cable? Sounds like a plan?

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Old 08-22-2023, 07:24 PM   #5
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Re: Replacing TH350 bullet and driven gear question

Quote:
Originally Posted by howzzzit View Post
Here's a glitch. The speedo cable will go back and forth about 1/8 inch each way, but won't unscrew. Ideas? Tried small channel lock . How about I take the bullet lock off and pry the bullet out with the slot and then try to unscrew cable? Sounds like a plan?
Then you'll need two pair of pliers unless the cable is loose and can use a soft jawed vice to hold the bullet? Sounds like a new cable may be necessary? "What Geezer Said"
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Old 08-22-2023, 07:42 PM   #6
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Re: Replacing TH350 bullet and driven gear question

If the "bullet" isn't turning, just use pliers to remove the speedo cable nut. It's bound to have corrosion and/or dirt in the threads.
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Old 08-22-2023, 07:55 PM   #7
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Re: Replacing TH350 bullet and driven gear question

Thanks. Pried off everything and was able to break loose the cable. Now the new natural driven gear is 19 teeth. The old gear counts 18 teeth. According everything I've read 18 teeth should be a dark brown color. Looks to me like the old one is just a discolored natural. Wouldn't think a brown would bleach out.
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Old 08-22-2023, 08:32 PM   #8
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Re: Replacing TH350 bullet and driven gear question

Are you replacing the bullet?
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Old 08-22-2023, 09:22 PM   #9
howzzzit
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Re: Replacing TH350 bullet and driven gear question

Yes as it was leaking. Trans gear is orange which should be 8 tooth. They show kits on the internet with a 8 tooth and 19 tooth driven gear. This transmission was rebuilt many years ago and probably has 25 miles on it. It's either the original driven gear or something laying around they just plugged in. The driven gear shaft is worn and doesn't click when inserting into the new bullet so that equals a leak. It's the color and tooth count that has me baffled.

Last edited by howzzzit; 08-22-2023 at 09:30 PM.
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Old 08-22-2023, 09:52 PM   #10
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Re: Replacing TH350 bullet and driven gear question

Don’t forget the inner o-ring for the new bullet.
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Old 08-22-2023, 09:57 PM   #11
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Re: Replacing TH350 bullet and driven gear question

It's there. That's what the click is I assume.
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Old 08-23-2023, 12:46 AM   #12
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Re: Replacing TH350 bullet and driven gear question

Here is a picture of the speedometer parts.
I have rebuild 100.s of these and never had to replace a bullet.
Replace the "O'" ring and a seal and your good to go.
The number one cause of oil leaks in this setup is warn shafts on the plastic gears. The steel shell never wears enough to replace. I believe you are on the right track to stop this adapter from leaking.
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