I just picked up a Cat D7e, serial 48A1697 and I am looking for what oil type I can use for the engine. The manual I found calls out SAE 30, is modern split weight better? It starts and runs great, only a few leaks. Also, since the transmission looks pretty good should I change it or leave it alone and just change the filter? The transmission oil is leaking into the right hand final drive but not very quickly.
TIA

modern multi grades are almost always superior. yes change all the oils and the filters. then you know its been done. its cheap insurance and check the filters and drain bungs for filings etc magnetic drain bungs are a good idea to show is there metal wear in something.

i would use delo gold 15w40 in the engine.
get in touch with your chosen oil company's tech advice line and get a recommended oils list for your machine. there is nothing really special about cat's own range of oils there made by one of the major oil companies and slap cat's label on their product.

somewhere i read that Mobil made all of Caterpillar oils

How many drain plugs do you have NCH?
my book says 5 but I can find only 3: the bevel gear plug toward the back of the machine, and the steering clutch plugs. I can't find the torque converter housing plug (center toward the front) or the oil cooler plug.
I can't find the oil cooler. i know that on machines with electric starters its on the left just above the starter. but mine is a pony starter.

I don't know, I haven't spent much time under the machine yet. I just got it delivered last week and haven't had the time.

It's really quite pleasant under all that beautiful iron, especially nice and cool on a hot summer day.

How do I identify which hydraulic system I have between the 171 and 181 system?

Early D7E options are below. 171 is for tilt with cable blade.
Craig
 

 

So I have the 181 with a separate tank? I have a large floor mounted lever on the right for the blade raise/lower and small lever on the left under the transmission control for tilt. There is a small tank on the floor on the right side too. But the radiator screen looks to have the 173 tank under it,

would I use the same oil in the transmission or use tractor transmission oil?