Chaffee Transmission Questions

[rob love]

This might be a source: http://www.fatsco.net/hydramatic.html

[Malcolm Towrie]

Originally Posted by rob love

This might be a source: http://www.fatsco.net/hydramatic.html

From my searches, the heavy duty cooler in the Chaffee, M5, and M135 tranny was unique to military applications and wasn't used in civilian cars or trucks, so Hydramatic parts suppliers like autotran and fatsco don't have cooler parts.

Malcolm

[rob love]

Fatsco tailor some of their kits directly toward the military trucks......wouldn't hurt to ask them. Then again, the military hydromatic is such a small segment of the market, it is hardly worth any companies time to have the parts custom made.

[BCA]

I am not sure if the G200 and G749 seals and gasket and retainers are the same. I don't have the full G200 Ord9 book to compare with G749 book.

[Malcolm Towrie]

Brian, this website below lists some specs for the 5342366 part shown in the G749 manuals. The cross sectional shape (u-cup) and the dimensions shown exactly match the ones I removed from the Chaffee,so I'm pretty confident these are the same part.

Do you have any?

Also part # 5342367?

Malcolm

https://www.wbparts.com/rfq/5330-00-534-2366.html

[Malcolm Towrie]

As a followup, I have ordered the cooler from Brian Asbury;. He also has seal and gasket sets for the G749 Hydramatic which include the cooler seals(and probably other gaskets and seals I need, because there are some significant differences between the civvy trannies and the military one) so I have ordered one of those. I think I'm good to go now.

Thanks for everyone's help, especially Brian.

Malcolm

[Malcolm Towrie]

To anyone with a Chaffee tank who finds this thread, the NOS G749 Hydramatic seal and gasket kit is useful because it has the round gaskets and v-cup seals necessary to seal the cooler in the pan (but see below). However, the pan and side cover gaskets don't fit. And the clutch apply piston rubber seals are the old style that need the brass expander so they still seal when they get hard and brittle after a few years. Modern Hydramatic kits have piston seals that don't require the expander.

The v cup seals for the cooler have the number AN6225-25 on them which is still available. Buy the 90 durometer ones in Buna N (nitrile).

The round gaskets can be made with 1/16" material.

Pressure test the cooler compartment to a few psi with air. The cover on mine was warped and leaked until I used RTV on the gasket. Dribble water into the two interspace drains and look for air bubbles.

Dribble water into the interspace drains and apply a couple of psi with a rubber -tipped blow gun to confirm the v-cups seal.
Beats finding the leaks when it's all installed in the tank.

Malcolm