BillMcGee

Decided to have my 92 D250 repainted. On a visit to check progress, I noted this fan unit--had no idea what it was. Have since learned it is an aux transmission cooler. I have never serviced this unit. Would appreciate advice.

Jim Lane

Here is everything you need to know about the cooler.
https://www.dieseltruckresource.com/...cooler-264993/

I just replaced all of the hose a few years ago just because.
It requires special high temperature oil resistant hose,
I used Hayden 1/2" TOC hose.
My truck took over 20 feet of hose.
There is also a low temperature bypass inside the frame rail.
Jim

BillMcGee

Jim, Thanks much. Do you know if there is any scheduled service for this unit? No problems noticed. Transmission working fine. Don't often pull heavy load--boat and 3-horse trailer periodically. All flat driving with no major hills. Appreciate any advice you can offer. Bill McGee