Name of this tranmission part?

[emil77]

Hi guys,

My truck is leaking tramission fluid from this part, what is it called so I can have it replaced?

[charx2]

Ihad the exact thing happen on mine. That box is a gear reducer I think and it's for your speedometer, it reduces or speeds up your gear to makes it read the correct mph. Your problem is what is called the "bullet" or gear housing or something like that. It's actually under that reducer box. I really can't remember the name of it at the moment but someone should be able to name it or when I think of it I'll repost. Hope that helps. What I did was just replace the entire "bullet" and it fixed the leak. I'm assuming you have a th350 right?
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[charx2]

http://compare.ebay.com/like/2306002...=263602_325002 this is what you need. You can get it from your local trans shops.
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[Daddy Brim]

Before I bought that part I would replace the O-Ring and see if that helps.

[charx2]

My problem is I had a hard time finding the o-ring and there are actually 2 of them on it. One is inside of the bullet which I don't think you can replace so I just got the whole thing for like $11 bucks I think and haven't had a problem since.
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[67Slider]

I bought a new o-ring from a loacal hardware store for .30 and it fixed my leak. Jack up the back as high as you can before you pull it, and you will only lose about 1/2 quart or less tranny fluid. Take the 'sleeve' down to the hardware store and they should have a box of o-rings to pick from. My th350 doesnt have the inside oring and I don't have any leaks.

[emil77]

Originally Posted by charx2

Ihad the exact thing happen on mine. That box is a gear reducer I think and it's for your speedometer, it reduces or speeds up your gear to makes it read the correct mph. Your problem is what is called the "bullet" or gear housing or something like that. It's actually under that reducer box. I really can't remember the name of it at the moment but someone should be able to name it or when I think of it I'll repost. Hope that helps. What I did was just replace the entire "bullet" and it fixed the leak. I'm assuming you have a th350 right?
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Hi, so the "bulllet" you showed a link for, it sits inside that box on top of that nut? How about that stuff under the nut that looks like it's been compressed? Can't I just replace that whole transmission piece? I think I have a th350, how do I know for sure?

[67Slider]

The bullet is the piece that is inside the transmission tail housing. Loosen th 7/16 bolt and the metal tab will move out of the way. Then you can remove the sleeve or 'bullet'. There will be another gear that slides out the other end of the sleeve. That is your driven gear for your speedo. The sleeve will have an o-ring that probably needs replaced. If the o-ring doesn't fix it you can buy a whole new sleeve for 10-15 bucks. You can tell what type of tranny you have by the shape of the pan. Do a search on transmission ID and you should be able to match it up pretty quick.
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[emil77]

Thanks for the info, I checked the transmission, it is a THM 350.

[charx2]

Yeah, just take off that reducer box and you will see what we are talking about, it's a fairly simple fix. Like has been said, it could be a .10 cent o-ring or you may need a new bullet. I opted for the bullet because it's only like 10-15 bucks and I knew i would never need to mess with it again.
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[emil77]

Originally Posted by charx2

Yeah, just take off that reducer box and you will see what we are talking about, it's a fairly simple fix. Like has been said, it could be a .10 cent o-ring or you may need a new bullet. I opted for the bullet because it's only like 10-15 bucks and I knew i would never need to mess with it again.
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Thank you for the quick reply!

[emil77]

Update: Talked to my mechanic today, he said he already replaced the o-ring on that "bullet" part. So do you guys think the o-ring could be bad or can I just replace that whole housing?

[emil77]

Btt.

[67Slider]

Just go with new one then.
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[emil77]

Does anybody know the name of the housing on top that has those phillip screws?

[emil77]

Btt.

[mr48chev]

Originally Posted by emil77

Does anybody know the name of the housing on top that has those phillip screws?

The box that attaches to the "bullet" and has the speedo cable attached to it is a speedometer correction/calibration box.

They are used in the heavy truck industry to calibrate the speedometers of semi trucks and the 4x4 guys use them to recalibrate the speedometers when they change tire size without pulling the transfer case off the transmission and changing the drive gears.

They have little gears inside like a set of quick change gears and you run the truck down the road and figure how much the speedometer/odometer is off and go back and make a gear change in the box to get the speedometer corrected. When I worked at Ryder truck rental in Waco, tx it was something that they checked/ did on every new truck that came in or on trucks that got a tire size change.

The first thing I would do is figure out exactly where the fluid is leaking. Wipe it off and maybe flush it off with brake cleaner and then take a short run down the road and check for leaks. as soon as you see fluid starting to seep out you can tell exactly where it is leaking and go from there.

On that particular box I think that you could go to a big truck parts house or dealer's parts counter and find pieces for it.

[emil77]

Great info, thank you.

[emil77]

Update:

So we changed the "bullet," the leak slowed down alot. But still it drips fluid a little bit, it's from the 2 areas I circled on the pictures. It's like two little pins or something that hold that "box" together, the leak comes from those pins. What's the name of that whole box looking thing, can I just change the whole box? Should I change the whole box or just live with it? The leak has slowed down alot now, it just drips a small amount.

[Fldawg]

The name of the part is a speedometer adapter made by stewart warner, it's hard to find them anymore but you can get the gears and the little gasket that goes between it maybe that will stop your leak,

[ol'blu72]

From what I understand there is not supposed to be fluid in the "box". Any fluid that leaks past the seals into the box will leak out.

[emil77]

Brad, let me understand you correctly. There is no tranny fluid in that box, correct? So if the tranny fluid is "appearing" to leak from there, it means somewhere else tranny fluid is leaking then falling onto the box?

[charx2]

Yes, no fluid in that box. If its leaking try to find the leak. Take off the box and clean it up. Then check evey so often to see where it's leaking from.
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[emil77]

Thanks for the help.

[emil77]

Update: The bullet was changed, oil pan and valve cover gaskets changed also. Since Thursday not a single drop of oil under the truck!