CHECK YOUR DIFFS...

diyer2 · May 4

You have a choice in life, to trust or not to trust. I trust nothing/ no one unless it's done by me.

Assembly line assembly leaves lots of chances for mistakes and no manufacturer has quality control you can count on because it costs money.

rdonarski · May 4

Speaking of trust. Some years ago I was on a trip to remote Maine. In the middle of nowhere, my wife ran over something with our Honda Accord and blew a tire. Put the spare on and found it extremely low on air pressure. Had a very hard time finding a place where I could add air. Now I check it once a year. It has never been low since. I'm leaving on a cross country trip next week and thinking about that I decided I should check the spare in my CRV. `Turns out it only had 20lb instead of 60. Bought both of these vehicles new. Wondering if Honda is sending them out low from the factory.

Grumpy Bear · May 4

7 hours ago, Jettech1 said:

So what you're telling me is that it does use clutch packs for LS. That's cool. I'm very familiar with that type of LS. So knowing the conditions I live in, and I respect your advice as always, would you use a 75-140 in my climate? And yes the GM synthetic is kind of low. I read an article one time that said Exxon/Mobil makes the lubricants for GM. Is that still true?

The G-80 is a Clutch Locker and not a clutched LS. It doesn't use springs to apply but a cam that puts enough clamp on the clutch to LOCK it. There is no slip-based torque bias. Because it locks the clutches don't wear out like the old LS units did that by designed slip in 40K miles. As the film will show it cannot lock up when the truck is over 20 mph.

GM spec on oil is a GL5 which has LS friction additives in it. They use the same fluid in the G-80 and Open differentials and older LS's. Point is the viscosity has nothing to do with clutch friction. Viscosity is the fluids 'internal friction". You can increase the viscosity without hindering clutch function.

A more viscous fluid MAY quite down a worn gear set. But it won't repair a damaged gear set or pitted bearing races. Nor will it keep if from failing if damaged. You are the boots on the ground and only you know what you're working with.

I put 75W140 in the wife's AWD rear diff in her Terrain when it got a bit noisy. Box has 200K on it. Been in there two northern Illinois winters without issue. Quite as a mouse. But it never ran out of or low on oil. Just got like me, old. Now having said that IF the 75W110 would have been available the day I did the fill I would have used that.

Pryme · May 4

8 hours ago, Grumpy Bear said:

If the question is will just a change of viscosity kill the clutchs.....no. Many gear oils will shear down one grade within a few thousand miles. Find the GM synthetic on this chart and weep. Red Line makes a 75/110 if it's a bit loose. They also make a 75/140 and an 80/140. AMSOIL also makes a 75/110.

Happy I drained the factory fill(which was low like they all seem to be) after a nice break in period and switched to severe gear. Not saying I can actually feel or notice any difference but from everything I’ve researched, it is a superior fluid.

the8rotor · May 4

Appreciate y'alls input and experience on this. Speaking of trust, been 20 years since I trusted a car/truck forum . I appreciate links/references/publications to back up information like I see on here.

My half ton Chebies all ran Amsoil severe gear and worked great. I'll be checking and swapping my 24 here soon. Well, checking will be today .

@newdude can you possibly confirm the 2024 gassers have the same fill levels on the front and rear diff as the 20-23s? I'm assuming they are - but this is GM we are talking about

64BAwagon · May 4

GM doesnt fill the diffs, they come as a complete assembly from American axle.

Pryme · May 4

4 hours ago, 64BAwagon said:

GM doesnt fill the diffs, they come as a complete assembly from American axle.

We all need to call American axle and go Karen on them. Or would it be Ken?

the8rotor · May 4

2 hours ago, Pryme said:

We all need to call American axle and go Karen on them. Or would it be Ken?

Depends on how you identify

Jettech1 · May 5

3 hours ago, the8rotor said:

Depends on how you identify

Have I mentioned lately that for 0 dollars a day you too can help Budweiser find their true identity?

Jettech1 · May 5

12 hours ago, the8rotor said:

Appreciate y'alls input and experience on this. Speaking of trust, been 20 years since I trusted a car/truck forum . I appreciate links/references/publications to back up information like I see on here.

My half ton Chebies all ran Amsoil severe gear and worked great. I'll be checking and swapping my 24 here soon. Well, checking will be today .

@newdude can you possibly confirm the 2024 gassers have the same fill levels on the front and rear diff as the 20-23s? I'm assuming they are - but this is GM we are talking about

This is why I love this site. There are people like grumpy, newdude, pryme, etc etc that know way more than I do about these trucks that are fortunately willing to share their knowledge about them when you have a question. That recent post of grumpy's for example, I have not taken the time to educate myself on the G80 rear diff. He provided me with a ton of information and a video to help me learn it!!! How much better can life get? The knowledge and the willingness of people to help others is here on this site and I LOVE IT!!!

the8rotor · May 5

3 minutes ago, Jettech1 said:

This is why I love this site. There are people like grumpy, newdude, pryme, etc etc that know way more than I do about these trucks that are fortunately willing to share their knowledge about them when you have a question. That recent post of grumpy's for example, I have not taken the time to educate myself on the G80 rear diff. He provided me with a ton of information and a video to help me learn it!!! How much better can life get? The knowledge and the willingness of people to help others is here on this site and I LOVE IT!!!

Great stuff. Happy to be here and joining the fun and knowledge!

Jettech1 · May 5

1 minute ago, the8rotor said:

Great stuff. Happy to be here and joining the fun and knowledge!

Damn glad to have you here!!

64BAwagon · May 5

I am sensing a building sentiment towards a group hug ? Dont go gettin soft here guys

the8rotor · May 5

Update on my 2024 - front diff is within a tenth of an inch to bottom of fill hole. All good. Rear? 3/4" from bottom of the fill hole and no drain bolt .

Assuming my rear has the same specs as the 20-23s, I'm a little low on the rear. Ugh. At least y'all alerted me to catch this before I really got after it towing.

the8rotor · May 5

@newdude really sorry to keep bugging you, my dealer is of no help.

Can you confirm rear fill specs are the same on my 2024 as a 2023, as well as fluid being 75w90 for the rear? Manual says "see dealer" and my dealer is not helping.