normal maint. need suggestions

[dean o]

planning to change trans fluid and diff fluid.truck has 256,000 miles. i do not have owners manuel for capacities or fluid types. any suggestions or tips would be helpful. also do you recommend gasket or rtv or both for insp. cover replacement. my truck is 2000 7.3 f250 ext. cab 2wd with 6-speed manuel and 3.73 ltd. slip. thanks for your help.

[klhansen]

The ZF-6 tranny takes 6 qts of ATF. I'd recommend a good synthetic like Mobil 1 Syn ATF. The drain plug can be tough to get out. It's an o-ring sealed plug and uses a 3/8 square recess. But don't try using an extension bar, as they tend to deform at the ball that retains the socket. I've ruined two of them (they were cheapos though). If you have a 3/8 breaker bar put that in an give it a tap with a mallet to loosen the plug. Be careful when you pull the plug loose as that ATF comes flying out pretty fast.

I believe the rear axle takes almost 4 qts of 75-140 gear oil. (If you have your owner's manual, the specs are in there, If not, check here: http://www.thedieselstop.com/faq/949...er%20Guide.pdf ). Since you have a limited slip rear axle, be sure to get some friction modifier or use a lube that has it already in it (some of the specialty brands like Royal Purple do).

If you get everything cleaned up well (brakeclean on the cover and gasket surfaces) just use a good RTV like Ultra Black. Let it set up overnight before putting the lube in and you'll be good.

Welcome to TheDieselStop

[RT]

You can get a copy of your owner's manual here - https://www.fleet.ford.com/maintenan...ls/default.asp

I personally like to use a gasket for the differential - it didn't come that way, and most of the guys use RTV, but I have never once had a leak using the gasket. Its FEL-PRO Part # RDS55394. Use synthetic 75W140 in the rear axle - 6.9 pints. If you pull out the speed sensor on the top of the pumpkin, its easier to fill it through there.

The tranny uses Mercon ATF. A lot of the guys use Mobil 1 in there. 5.8 quarts.

[01f25073]

Here is a tip for all who read this concerning fluid changes: When in question, capture all fluid removed from what you are servicing in an isolated container and measure the amount that came out. Then, only put that amount back in initially and after that adjust to the proper amount. I have found in my truck that the manual always states more fluid capacity than what I remove. My manual states my transmission holds 17.7 quarts but I only got 15 quarts out when I serviced it. Therefore, I added 15 quarts and the level on the dipstick has been exact ever since. The great thing about differentials and transfer cases (on 4X4's) is that they have a fill hole so that there is no question as to the proper amount of fluid. Hope this helps you!

[RT]

Good advice - I forget some things I take for granted. I don't measure like you did, but I never blindly add to the amount listed in the manual. I know some residual is always around. I just use the manual's capacity as a guide for how much to have on hand - like he said - always get close and then start checking to get it to the right level.