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Mystery part in 3406B oil pan

Almach · 2026-07-11 08:35

I don't know what this is. AI said it could be a piston cooling jet and a slave piston for the Jake brake. from what I'm seeing it is not either but I need to put the oil pan back up and want to make sure. I dont have a jake on this truck.

Replies21
  1. #1Tyler d4c2026-07-11 09:10

    Kinda looks like the rod our of the fuel/air control that hooks in to the fork in the governor housing

  2. #2Tyler d4c2026-07-11 09:11

    Thats it

  3. #3DDoug2026-07-11 09:52

    I thought it looked much like the Turboencabulator......

  4. #4Almach2026-07-11 11:08

    you are a bad ass! I will pull it i guess. i wonder if someone did a repair and dropped it. I really appreciate that!

  5. #5FWD2026-07-14 20:02

    I was changing oil in a truck I had with a Big Cam 4 Cummins. After the oil drained I stuck my finger in the drain hole and pulled a small piece of steel that was half round and had a 5/8" hex part for a wrench. Why I stuck my finger there, I will never know. I filled it with oil and the next day I would be hauling near the Cummins dealer, so I stopped there and service mgr got one of the mechanics to look at it. It was something for the jake brake, the guy knew right away what it was. FWD

  6. #6Almach2026-07-14 20:39

    I guess if you drop something all you can do is hope for the best.

  7. #7Truck Shop2026-07-14 21:44

    Unless it's a Cummins 855. While installing anything on top end especially jake housings, a case of butterfingers or a hangover dropping a 1/2" nut and only hoping it made it all the way to the pan can prove disastrous. If caught up in cam followers and engine started it's about a 90% chance the block, cam & follower will become scrap iron. It's a drop the pan and find at all cost.

  8. #8Almach2026-07-14 21:48

    Agreed but the last guy didnt.

  9. #9Truck Shop2026-07-14 22:03

    And he was a fool.

  10. #10FWD2026-07-15 16:13

    I don't know what it was, but it wasn't a nut, but it had a hex for a wrench but it was broken. I used it another day before they could work on it, but the mechanic said don't use the jake brake. I ran the truck several more years and about 250,000 miles without a problem. It was an NTC-400 Big Cam 4 which would be an 855 I believe. FWD

  11. #11Truck Shop2026-07-15 16:24

    Don't know of any parts that use a hex wrench other than a some solenoids on later model IV jakes.

  12. #12chidog2026-08-05 00:55

    There is kinda no excuse to drop anything in an engine. If you don't know how to prevent that from happening you have no business working on one. A bolt in the wrong place in the oil pan can stop the oil pump on a D342.

  13. #13Coaldust2026-08-05 03:22

    You could glue a big magnet onto the pan to hold it until the next bearing roll- in.

  14. #14Truck Shop2026-08-05 07:42

    And there's no excuse for running a caution light that's really stale but people do it--crap happens. Dropping things happens, gravity.

  15. #15HarleyHappy2026-08-05 13:04

    I’m trying to remember but I was doing an engine on a stand, think it was a Kubota. I had the head on and torqued and think I had the injectors in and was doing something and I forget what it was but something flew up in the air and landed in one of the glow plug holes. I was trying sticky tape, forceps, surgical grippers, everything I could think of and I was literally losing my crap. Wife came out to the shop, after hearing me yelling and swearing. She asked, I explained, she says, why don’t you flip the motor over. I of course explained why that wouldn’t work and I would have to order another head gasket. Soon as she left, I flipped it over, blew some air up in the glow plug hole and out came the piece. Now I remember what it was, it was a knurled cap nut for the #4 glow plug.

  16. #16Welder Dave2026-08-05 16:25

    My friend who's a mechanic changed the glow plugs in my Kubota. One was bad. I got new NGK(OEM) glow plugs from Napa that came with regular nuts. He said the nuts are way better than the Kubota knurled nuts. Easier to loosen if they're stuck.

  17. #17Truck Shop2026-08-05 22:45

    Friend working in a foreign car shop was replacing cylinder head on a Fiat 128. The air cleaner on those is held in by 8mm nuts on 4 studs {Weber}. Anywho he fumbled a nut the bumped the throttle linkage causing nut to fall into cylinder, tried all sorts through plug holes no luck. Off came the head, reinstalled fired it up--ran good for about 5 minutes then seized and bent valves. All holes in head gasket on a 128 line up except one--the oil feed rifle, roasted cam also.

  18. #18Tyler d4c2026-08-05 22:50

    Dropped a screw in the intake of my drz400 was a got excuse to install more compression. Lost my share of tools and parts off belt lines in to piles of stone or coal Thing is gravity never fails

  19. #19Truck Shop2026-08-05 22:54

    Even the Great Wallendas feared gravity.

  20. #20chidog2026-08-06 17:22

    I know of a shop working on a W-8 VW engine, stupid of them(VW) to have dowel pins on the intake manifold that can drop into a port. Split the piston, cracked the cylinder wall, no way to prevent that other than retaining those pins better.

  21. #21DDoug2026-08-06 18:14

    "well.....it looked good on the screen".....