Gear oil for trans and rearends

[Rawze]

(12-10-2016 )Brock Wrote:  Odd. I was told by Eaton that under no circumstances could you use a 75/90 gear lube or anything of that nature. They say there are galleries that are not wide enough to support the thicker oil and you will run components dry causing premature wear.

I wanted to know because I was considering doing it.

For an Autoshift? - I have no idea if that is true or not but not likely, for a regular 10, 13, 0r 18? - I own a 10-speed eaton ...

COMPLETE AND UTTER HORSE-shi#t!

Take a few truck Trannies apart and find me those passages, then make that same statement.

Another complete horse-shi#t statement I hear over and over is "you can't run down roads with them in neutral" --- MORE COMPLETE AND UTTER HORSE-shi#t!

There is one thing you CANNOT AND SHOULD NOT do with them, and WILL cause harm to the synchronizer though while in neutral. Fliping the High/Low Low/High while in neural, even at speeds as low as 30 mph is bad for them. it makes it spin up out of control,.. and I have seen a lot of drivers that I do test drives with do this as a bad habit. You can hear its subtle high-speed whine when they do this.

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I spent some time with someone who has re-built them for many many years early this past year that literally knows every knook and cranny and weakness in them. He has seen every abuse that has been thrown at them. I took a hard look as he explained with my own skeptical eye too. I know a lot about gearboxes myself in general. We discussed exactly those things, and looked at in high detail. This is because my own truck has more than a million on it and NOT A SINGLE DRIVE TRAIN COMPONENT, NOT EVEN THE CLUTCH has any high amounts of wear in them yet. --- My tranny and drive train has only been in top gear 14% of that million miles according to my long term data on my qualcom, and it has to be pretty close to that. -- That thing is in neutral unless it slows down below 55, and it gets shifted in and out of gear about 300 times a day because neutral is our preferred gear at all times.

Every vehicle I have ever owned, I have driven this way. You get 2x more engine live, 2x more drive train life, etc. and that is also why I also hate automatics.

[386lover]

(12-11-2016 )Rawze Wrote:  

(12-10-2016 )Brock Wrote:  Odd. I was told by Eaton that under no circumstances could you use a 75/90 gear lube or anything of that nature. They say there are galleries that are not wide enough to support the thicker oil and you will run components dry causing premature wear.

I wanted to know because I was considering doing it.

COMPLETE AND UTTER HORSE-shi#t!

Take a few truck Trannies apart and find me those passages, then make that same statement.

Another complete horse-shi#t statement I hear over and over is "you can't run down roads with them in neutral" --- MORE COMPLETE AND UTTER HORSE-shi#t!

There is one thing you CANNOT AND SHOULD NOT do with them, and WILL cause harm to the synchronizer though while in neutral. Fliping the High/Low Low/High while in neural, even at speeds as low as 30 mph is bad for them. it makes it spin up out of control,.. and I have seen a lot of drivers that I do test drives with do this as a bad habit. You can hear its subtle high-speed whine when they do this.

=====


I spent some time with someone who has re-built them for many many years early this past year that literally knows every knook and cranny and weakness in them. He has seen every abuse that has been thrown at them. I took a hard look as he explained with my own skeptical eye too. I know a lot about gearboxes myself in general. We discussed exactly those things, and looked at in high detail. This is because my own truck has more than a million on it and NOT A SINGLE DRIVE TRAIN COMPONENT, NOT EVEN THE CLUTCH has any high amounts of wear in them yet. --- My tranny and drive train has only been in top gear 14% of that million miles according to my long term data on my qualcom, and it has to be pretty close to that. -- That thing is in neutral unless it slows down below 55, and it gets shifted in and out of gear about 300 times a day because neutral is our preferred gear at all times.

Every vehicle I have ever owned, I have driven this way. You get 2x more engine live, 2x more drive train life, etc. and that is also why I also hate automatics.

Could you explain what you mean by "in neutral"? Are you saying that if you are not actively accelerating, that you take it out of gear? Or am I misunderstanding you?

[snailexpress]

Out of gear.

[Johnboy]

Take this for what it's worth most of this is second hand info.
The gear oil issue was out of curiosity on my part the reason I asked is I personally know a few people from down in the sticks of Kentucky that run 80-90 in everything trans and rears one, it's cheaper two,it last longer three, it lubes better my personal opinion.
Now think about this eaton told me the sulfur content is to high and eats the brass or something to that effect in 80 -90.
Personally I think they came up with this b.s. because nobody would buy synthetic oil because of the price.
Food for thought one of the fellows from ky got 1.7 mill on the original rearends before he changed them due to a worn barring and he wanted a different gear.
Maybe someone on the forum can answer this what's the difference between a drive axel or a trans from the days of 80-90 and the ones today I bet some of the parts interchange.
More food for thought I can show you a freightliner that's in the shop now for the third rearend in a year and it's 2 or 3 years old.

[Rawze]

(02-04-2017 )386lover Wrote:  Could you explain what you mean by "in neutral"? Are you saying that if you are not actively accelerating, that you take it out of gear? Or am I misunderstanding you?

Absolutely.

Truck has 1.03 mil on it. I finally replaced my clutch, input shaft, ipt. shaft bearing, rear motor mounts, rear main seal, had the flywheel turned, replaced the mid-shaft bearing, and replaced all the u-joints on the front drive shaft. This is the first time everything has been apart.

My old clutch still had half its life left on the pads. About 25% of the end of one of the springs had failed and snapped off. It was rolling around in there, and that is why the clutch started acting up. It made it difficult to get into gear at times randomly. - At a million miles, I simply replaced everything relevant to having it apart out of safety concerns.


- While the tranny was out I had the top plate removed and the insides looked at very closely. They tried their damnedest to find some excess wear in it from running it out of gear its whole life. -- There was less wear in that tranny than any he had ever seen with only 1/4 the miles on it. In fact, he said there was less wear than a fresh re-man tranny on the inside. He went out of his way to find some wear and effects from me driving it in neutral its whole life. -- Even the play from the gears to the shafts were checked. -- Like new still.

BTW: I run Shell 75/90 synthetic in my tranny (and rears). He said every tranny they have had apart where someone runs 75/90 in them, they always have less wear than people who use only 50-wt oils.

Input shaft after million miles+ ..
   

Forks, still no wear after million miles in mostly neutral ..
   

We have 10-speed tranny and we shift between 9th and 10th gear about 200-300 times a day, and keep it in neutral unless we have to make power to get back up to speed. We do this every day and have since truck was brand new. It is because we drive 55-57 and coast absolutely as much as possible to save fuel.

Here is the actual results ...

Close-up of 10th gear after million miles (the smaller gear in the middle) ..
   

Close-up of 9th gear after 1 million miles (the smaller gear in the middle) ..
   

Here is an overview of the rest...
   


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That is what the results are. You can see a tiny bit of wear from use, but nothing that would indicate anything harmful at all.

[Johnboy]

You most certainly can run them in neutral for short distance, as long as they are in high range, and the engine is running turning the pump inside the transmission.
In a towing situation this is no different than going down the road.
That in neutral damage happens when the oil is not being pumped It frys the back section of the transmission. If that statment were true wouldn't it mess up all of the cars you see towed behind an rv. And yes I know they are modified to do so with transmission lines from the rv itself to flow the fluid. I understand what you are doing rawze by going to neutral that takes some skill and good timing to do so.

[Rawze]

(02-05-2017 )Johnboy Wrote:  You most certainly can run them in neutral for short distance, as long as they are in high range, and the engine is running turning the pump inside the transmission.
In a towing situation this is no different than going down the road.
That in neutral damage happens when the oil is not being pumped It frys the back section of the transmission. If that statment were true wouldn't it mess up all of the cars you see towed behind an rv. And yes I know they are modified to do so with transmission lines from the rv itself to flow the fluid. I understand what you are doing rawze by going to neutral that takes some skill and good timing to do so.

We run neutral more than any other gear, and I have done this on all my vehicles. It is not unusual when we are heavy to go 30+ miles at a time in neutral before putting it back into gear. We know all the places where this can be done across the country, and we drive like this not even realizing it we are so used to driving this way. it is just normal for us.

[Rawze]

Just to let everyone know, it is a good idea to replac e rear engine mounts when tranny is out. it is a LOT easier to replace them that way. Here were mine after 1 million miles. The rubber on them was just starting to tear and crack. i suppose if we had driven the truck harder, they would have been much worse. Also the bottom bushings that hold them to the frame were worn down pretty badly.


   

[Magard]

What's your brake wear like taking it out of gear. I could see driving 57 in a 70 speed limit you probably just let it roll and let wind hold you back. Driving 57 in a 55 looking over your shoulder all the time, I would just be on the brakes a lot I would think. How does that work out in the slower speed limit areas?