500 Hour Service Interval Guide for a John Deere 85G Excavator – Part 6
Written by Luis Montes Updated On November 15, 2024

Previously, we changed the cabin air filter.
In this post, you’ll learn how to replace the final drive oil on a John Deere 85G Excavator.
We also have a video version on the Fortis HD YouTube channel. Check it out.
Need to save time? The following table shows every filter you need for the complete 500-hour service interval:
| Item | OEM | Part Number | |||
|---|---|---|---|---|---|
| Aftermarket equivalent | |||||
| Baldwin | Donaldson | Wix | Blumaq | ||
| Hydraulic Return Oil Filter | 4450002 | PT9443 | N/A | N/A | N/A |
| Hydraulic Breather Filter | 4437838 | PA5316 | N/A | N/A | N/A |
| Engine Oil Filter | MIU800650 | B161-S | P502051 | 51568 | N/A |
| Fuel Filter | MIU805005 | BF9910 | P553995 | N/A | N/A |
| Water Separator Filter | MIU802421 | N/A | N/A | N/A | N/A |
| Water Fuel Separator Housing + Plastic Bowl | MIA885254 | N/A | N/A | N/A | N/A |
| Pilot System Oil Filter | 4630525 | N/A | N/A | N/A | N/A |
| Primary Engine Air Filter | FYD00001541 | N/A | N/A | N/A | N/A |
| Secondary Engine Air Filter | FYD00001327 | N/A | N/A | N/A | N/A |
| Cab Fresh Air Filter | 4S00640R | N/A | N/A | N/A | N/A |
| Cab Recirculating Air Filter | FYA00011003 | N/A | N/A | N/A | N/A |

Table of Contents
Drain the Final Drive Oil

Start by parking your machine so the plugs of the final drive are in the following positions:
- Up plug – 12 o’clock.
- Level plug – 3 o’clock.
- Drain plug – 6 o’clock.
Get a plastic container to collect the used oil.
On this particular model — John Deere 85G — each final drive takes 1.2 liters of 85W-140 oil.
First, remove the top plug to release pressure within the final drive, allowing the old oil to flow smoothly and quickly out of the system. Use a ratchet with an Allen/Hex key (refer to the operator manual for the correct key size).
Remove the level plug. Oil should come out when removing the level plug. If not, there might be a problem with the housing or the seals.
Lastly, take out the drain plug. Old gear oil looks dark and has a particular smell — burnt or sulfurous.
We recommend sampling your gear oil at the time of service. Refer to the operator manual or the description in the YouTube link of this post for more information.
Add the New Gear Oil

Once it stops draining, reinstall the drain plug.
Start filling from the top plug using 85W-140 oil until it drips out of the level plug.The oil level should stay just below the level plug.
Give the final drive a good clean to check for leaks.
Next Post
In the final post of this series, we’ll flip over the cutting edge on the John Deere 85G Excavator.


