Info needed: Transfer case vent

[Jordan Baker]

There were two different vents used.

Please see attached GM Service Information Bulletin B29, Item 64 from December 12,1942

The early one was simply a pipe with a cap on it held on by a cotter pin "Fig2". The second version was the air cleaner type "Fig2".

These were introduced into production starting at serial number 1844332070.

[Barry Churcher]

Excellent job Grant.
Barry

[Paul Edwards]

GRANT! BRILLIANT!

Took the opportunity to photograph my own tranny today, it appears to be the early version (pipe/cap/cotter pin fig2) type, the vent exits vertically, hence why the air cleaner type had been butchered to fit under the cross rail. The air cleaner one would appear to exit at 45 degree slant.

Am I reading this bulletin correct, ie: the air cleaner type superseded the simple pipe/cap/cotter pin fig 2 type?

If so and all I need is the simple version then I recall there's one of these vents on the Jeep tranny, I wonder whether this wound fit?

Cheers,


Paul

[rob love]

I sounds like the air cleaner type was a product improvement, and that is was to be retrofitted onto the earlier transfer cases to replace the simple tube and cap. But in all seriousness, for the miles any of us will put onto our vehicles, nor the dirt we will subject them to, the nipple and cap would likely be fine.

If you are talking about the little nipple and cap on the jeep transfer cases, they are normally spring loaded onto a little check valve which will build up pressure to about 3 or 4 psi before reliving the pressure. They are usually 1/8 npt thread so would be pretty small for this application. However, with some bushings, it would work fine. The same nipple was used on the M35 deuce (and a thousand other vehicles) for that large transfer case for the last 60 years.

Edited to add: I had to look up the early Jeep transfer case breather and just saw that some indeed are a nipple with small cap retained b a cotter pin. But some sources are showing the pressurized cap which is more what I am used to. Someone with a WW2 Jeep will have to confirm if the nipple and cap type is 1/8 NPT.

[Jordan Baker]

The Jeep uses a similar vent on the transfer case. It looks like one of those would work just fine.

https://forums.g503.com/viewtopic.ph...82ecd34c49e6ee

[Paul Edwards]

Thanks Rob, Jordan,

I think for the miles I'll be doing the simple early version will suffice.

The Jeep version may be small but I'll check out the Jimmy or Dodge version that may be better suited.

Cheers,


paul

[Paul Edwards]

Guys,

Would the thread be NPT or BSP?

I'm assuming 1/2BSP 14 threads/Inch 21mm-18.5mm tapering.

Cheers,

Paul