I have never owned a diesel pickup but stumbled into a neighbor farmer selling his '97 F250 SD with 5 speed and 166K miles so I bought it.. It's very nice and has some rust underneath towards the back end. It's always been in a heated shop. The body is exc with only a little rust over one rear wheel well and a little bit of a cab corner. It's still shiny, original paint. So far I've put some brake lines on, batteries, belts, rear brakes and drums, oil change and fuel filter. I'm prepping to change coolant, back flush and add a coolant filter. Also change fluid in axles and trans..

My questions regard conflicting or difficult to find info on axle ID, correct gear oil weight, tire pressure, etc. For example, my differential is a code C5 but I can't find any info who made it so I can order the correct gasket. Tag photo shows 4L10 10 2 7010. Also S 132 N


I gather this is a LS 4.10 and I know to add 8 oz of friction modifier. But what weight gear oil? The owner's manual says 80W90 but on-line says a wider viscosity like 75W130 or some number like that.What should I use for my mostly summer driving? What axle is it so I can order correct gasket? I think it's 10.25" 12 bolt but the axle could be one of several choices. Does anyone know?

On the trans, it's a code C but there are two choices of 5 speed transmissions but no info on the internet on how to tell which one. How do I know what I have? It feels like a close ratio.
On tire pressure, I have 285-75 x 16 tires. The internet, for non-towing says 60psi, the book says 80psi and a local shop said 50psi. I'm only going to tow limited amounts over the summer and know how to inflate for that. What is normal tire pressure?
On the front axle, what kind does the tag show? I can't find what weight oil is correct and what axle is so I cn order parts when needed. There seem to be lots of choices and I can't find a good ID site for the tag that deciphers it.

Any info on any of the above would be much appreciated. I've searched and many of you guys will easily know these answers. I've searched for hours and still draw a blank. There just doesn't seem to be anything 1997 specific and I don't know which other years to lump it in with. This is a nice truck that will suit my occasional needs and I plan to take the best care of it that I can. Excuse the large photo but I don't know how to shrink it.

EDIT--Also, do you think it's OK to lightly pressure wash some of the engine and surrounding areas? Lightly means maybe 1000psi and quick in and out? I would do on a hot day and start it ASAP when done to dry things out.

Thank you in advance.

 

Sterling rear end, I use regular gear oil with friction mod at the store

Tire pressure is a guess. Get some chalk and do some chalk tests for tire wear. Then adjust for towing as needed.
https://www.intercotire.com/using_ch...20the%20ground.

Brake cleaner, Gunk engine cleaner, ATF and diesel and a garden hose to clean engine

 

The 97 F250s HDs, which you have, left the factory with a Sterling 10.25 rear axle, and a Dana 50 Twin Traction Beam front on the 4X4 trucks. 80 W90 gear lube is fine in both the front and rear axles. Ford used RTV when assembling the covers on the axles, so no gasket needed. 50-60 lbs. in the tires will give you a better ride if no loads are being hauled, more pressure is needed when more weight is added to the truck.

 

Very helpful. Thank you.
I'm going to change then rear axle fluid and would like to use the newer style gasket that doesn't need RTV. Is that OK?

 

Thanks for that link. It was very helpful and I'm getting up to speed on what I think is a wonderful classic truck with a bulletproof 7.3.

 

I have never used a gasket, just rtv. That said, I'm sure they have come up with a good gasket in the 27 years since these trucks were made. I think you are safe to use one.

 

'97 will have the S5-47 from ZF unless someone swapped in an earlier S5-42.

Any pics? Sounds nice

 

I have a couple pics. How do I post smaller pics rather than the giant one I did the first time?

 

Don't mind the size of pics, easier to look while on phone

 

Is there a way to post thumbnail photos that get larger when you click on them?

Here's in the barn before I picked it up. It wouldn't start and had been sitting two years. I know the man, who is now having trouble getting around, so I bought it sort-of sight unseen. He is an honorable and honest man and takes good care of his equipment. It worked out fine. I'm doing mechanical and delayed maintenance things now and will will get the underside cleaned and sprayed with oil in August.

Have to clean rugs, clean things up and clean wheels and little things. Bulbs, etc and keep it stock and honest. I need to tow tractors a few times a year and a few auction things. Maybe a few thousand miles and then it's back in the barn. Rinse and repeat.

 

Nice truck, a true survivor of the rust belt!

 

Great color, same color as my 95.

 

That's one of the best colors for this body style. We lucked out.

 

get a SD Alum finned Diff cover for the rear from dorman for 60 bucks
Some others have drain plugs in them but i like to look at the gears

 

For rear axle gear oil, I don't have any 80W90 in my shop so I have to go buy a pail. However, I do a whole pail of synthetic 75-140 and enough synthetic 75W90. I'm going to add 8 oz of friction modifier to the rear axle.

Can I use the synthetic 75-140 or synthetic 75W90 that I have or should I go buy some conventional 80W90?
Any help appreciated. I'm new with Fords like this and searching is very complicated with lots of thread drift.