Yes it is. All Mobil1 oil is synthetic

 

Clearly it is much easier to shift with 5W30 in there. That was obvious. The Chrysler service manual says 80w or 90w lube goes in there. So what is the exact effect of the lighter oil. It makes me think that the lighter oil gets pushed out of the way faster, hence more metal to metal contact with less oil. On the other hand lighter oil would get back in there faster to protect at higher speeds perhaps. What is the thinking on this?

 

I've never seen any info from Chrysler saying that the Getrag should be filled with gear lube. They recommend 5W-30 motor oil, or ATF if shifting is difficult in cold weather.

 

The reason for the 5/30 is due to bearing preload. Anything heavier and the bearings will not be adequately lubricated. The overfill is because of a design fault. The front input shaft bearings fail after 100,000 miles because of inadequate cooling. The factory level takes care of lubrication but does not cool the bearings adequately especially when working hard. The other design fault in the tranny is that the bearings are a little too small and can not take high torque lugging at low engine rpms. Try not to make it work real hard below 1500 rpms. You may notice a rattle sound below this speed. Put 5/30 in, add an extra two quarts and keep the rev's up before big power and the getrag will last forever. I just fill it till it comes out of the top bolt of the side cover and then add some more. I use an old suction unit like they used to use in garages in the 50's. It takes a while but it is reliable and does not waste any oil.

 

My last three trucks were all Getrags...
Overfilling them wont cause a problem with seals, etc, and your tranny will run better and longer!


to overfill mine, rather than fabricate anything. I removed the dust boot, removed the shift assy,( one snap ring and two side bolts) and poured it in there, works fine.....
If you search this forum under "getrag sight tube" there are a couple good threads about the different ways guys have rigged sight tubes, dipsticks and such to monitor the fluid level.

The Getrag doesnt have a fluid pump, it lubes via the gears being just slightly into the oil resivior and throwing the oil .. overfilling prevents the gear from not being in the fluid while on angles/slopes and allows for better lubrication. It alos runs cooler over-filled

I dont remember who it was, but one member even rigged a 12v pump and installed a spray head through the upper PTO cover bolt to circulate the oil..

 

Great insights, OldandRusty. Just what I was looking for. Sounds like you've turned quite a few numbers on the odometer. It's good to hear ya. Thanks.

 

Several have already done just that.

Search through the forums and you will find several accounts of this, along with pictures.

 

"The worst killer of manual transmissions we see on Dodge Turbo-Diesel trucks is a small, often overlooked, $10 part that is not even part of the transmission. The pilot bearing or bushing is pressed into the flywheel. It’s function is to support the forward end of the transmission input shaft, keep the clutch disc centered on the flywheel, and allow the input shaft and flywheel to rotate independently of each other when the clutch is disengaged. Dodge used a thin bronze pilot bushing on 1989-1993 trucks and a small, needle type pilot bearing from 1994 on.
Most lubrication related failures are totally preventable. Common causes include using the wrong oil, operating with insufficient lubricant, or going too long between oil changes. If you have a first generation truck with the Getrag G360, your transmission has inherent lubrication problems that can be partially alleviated by both overfilling the transmission with an extra quart of oil, and using only synthetic lubricant of the viscosity recommended in your owners manual." -from a knowledgeable source. Sounds about right for the above discussion.

 

http://quad4x4.com/Causes%20of%20Man...20Failures.htm

above is a helpful link

 

As BearKiller said there is a lot of different ideas how to over fill it.

Mine is the basic simple idea.
https://www.dieseltruckresource.com/...3&ppuser=40988
This is the PTO cover and the pointer is pointing to the bolt that i used for the dip stick.

https://www.dieseltruckresource.com/...1&ppuser=40988
This is the dip stock that i made out of a old coat hanger and were i store it when not in use.

Ok them pic's above are real small and hard to see..........here is some better ones



pointer (icicle) shows the top PTO Cover bolt that was used


This is were i attach my dip stick when not in use



And this is what my coat hanger/Dip Stick look like

Flash

 

I'm really learning something and enjoying all the ideas. Thanks Flash, and everyone else. I'm loving the resources here at DTR!!

 

Okay so can anyone decide on how much to overfill the getrag? One quart? Two?

 

1 quart extra is plenty.

 

How hot is this oil getting?

If you were towing or playing hard then why not install a remote engine oil cooler under the frame much like the optional heavy duty coolers on our automatics and then circulate it through a spin on filter using a 12-volt lube pump, you could circulate it from the bottom drain plug and return it to the fill hole or if it were me I would weld 2 pipe bungs to the top and bottom of the PTO cover and install a baffle.

I built a similar type system for my Mustang I raced back in the 70's.
The racecars had them for both the transmission as well as the differential lube oil.
Jim