What is the Best Gear Oil for a G360 Transmission. I put some 85W-140 in temporarily and I have seen numerous other oils used and so many different opinions. the 85W-140 makes it more difficult to shift in cold weather until it warms up. I know they recommend 5W-30 from Chrysler. I have a way to pump it in but it's only good if you have only that type oil in there. It's an old style Gear oil with the hose and wind up lever. I have some 75w-90 Amsoil which I had in it prior to working on it. I also know they recommend an extra quart because of the input shaft bearing which would make it hold about 4 and a half quarts. just like someone who knows a little more about it. I have seen a lot of different opinions, even 15W-40 Oils. Thanks for any help.

 

I believe the factory lubricant was 5W30 motor oil.
If you want to get fancy you can use Synthetic, and if you want to pour money down a hole you can use one of the fancier synthetics like Royal Purple or similar. Regular gear oil is probably much too heavy if the manufacturer says to use a lightweight motor oil.