CHECK YOUR DIFFS...

shadow gray 2020 hd · April 16, 2023

1 hour ago, 64BAwagon said:

The lower ball joints are tricky. There is almost no clearance and a locking coupler is definitely not going to fit. I have found that turning the wheels in the opposite direction from the one your greasing (turn right for left side and vice versa) will give you a better view of the fitting. I doubt that they are stuck, its more likely an issue with aligning the fitting with the coupler.

Sadly its common for oil change places to skip these due to the difficulty. Unless you get under it and check youre never going to see it until its too late and you have to replace a ball joint prematurely.

We had an older Colorado at work that required removal of the front wheels to grease, straight up bad engineering.

Thanks for the response. I changed couplers again and I ended up taking the wheels off and had my wife pump the grease gun while I held the coupler as tight as I could. That worked.

1 hour ago, Pryme said:

Also make sure you have a flexible hose attachment. Mine is like 18” and got everything.

Yep, have flexible hoses on the two main guns I use for my equipment and tractors. My pistol grip has a lock on coupler, and it just wouldn't fit.

Fwiw, I have three dealer service sheets from different services where it says they lubed chassis components, bottom right of below attached pic. Would assume that should include the front end, but I will be asking when I am at the dealer again for sure.

64BAwagon · April 16, 2023

I noted in that video that one of the upper ball joints had a failed fitting on it. When he released the coupler some of the grease came back out of it. This indicates a failed check ball and that fitting should be replaced. These are metric on our trucks.

Also note that he fills the joints a little too full in my opinion. The boot should swell a little but not to the extent that his did. You run the risk of ripping the boot or unseating and then allowing moisture and debris a way to get in. Sometimes more isnt better. As a general rule two pumps should be plenty unless its bone dry.

Other than reminding them to grease the front end next time I dont see much value in bringing it up, theyre just going to lie and deny anyways.

rdonarski · April 18, 2023

When I 1st saw this, I figured it had to be a fluke. Had some spare time the other day, so I decided to check it just for the heck of it. Ended up the rear was a full quart low and the front was 8oz. Hard to believe they can be doing this. I never checked differentials before unless there was an obvious leak.

Pryme · April 19, 2023

3 hours ago, rdonarski said:

When I 1st saw this, I figured it had to be a fluke. Had some spare time the other day, so I decided to check it just for the heck of it. Ended up the rear was a full quart low and the front was 8oz. Hard to believe they can be doing this. I never checked differentials before unless there was an obvious leak.

Yeah it’s completely unacceptable. Such a elementary thing to mess up. Makes me wonder what else might pop up.

how far down from the edge in the front was it to equal 8oz? Did you add til it dripped out?

my front was like 1/4” from the top and looked so fresh and new I kept that as is.

rdonarski · April 19, 2023

I didn’t fill either till they ran out. A little bit below the edge. The 8oz was probably about 3/4” down.

Jettech1 · May 3, 2023

I finally got a chance to check mine today. I squeezed a full qt in the rear diff and it's still not up to the fill hole. I'm going to check it again tomorrow afternoon and see exactly how far below the oil fill it is. This is stupid and uncalled for.

77xbody · May 4, 2023

2 hours ago, Jettech1 said:

I finally got a chance to check mine today. I squeezed a full qt in the rear diff and it's still not up to the fill hole. I'm going to check it again tomorrow afternoon and see exactly how far below the oil fill it is. This is stupid and uncalled for.

Had to use a full quart in the back diff and it put me about a half inch below the fill hole.I can't believe they think it's acceptable

Jettech1 · May 4, 2023

8 minutes ago, 77xbody said:

Had to use a full quart in the back diff and it put me about a half inch below the fill hole.I can't believe they think it's acceptable

This is total BS. I need to check my front diff tomorrow. God only knows how low that one is.

Jettech1 · May 4, 2023

Here's something else I've been wondering and hoping @newdude or another person that knows the answer can chime in. Because I live in Atlanta and it rarely goes below freezing during the winter and is basically hot as hell for many months, would it be a recommended choice to install 75-140 synthetic LS gear oil in the rear diff? I'm just wondering if it would mess with the LS portion of the rear diff if I did or would it work fine for the climate I live in?

Edit: do these rear diffs use clutch packs for the LS or the conical version?

Edited May 4, 2023 by Jettech1

the8rotor · May 4, 2023

This... this whole issue is beyond disappointing. I'll be checking mine this week

Jettech1 · May 4, 2023

16 minutes ago, the8rotor said:

This... this whole issue is beyond disappointing. I'll be checking mine this week

It is for sure. And there's one thing I haven't mentioned that I noticed a few days ago when going 80mph on I-85 north that has me totally pissed now. I started to notice a slight driveline whine at those speeds. My truck is so quiet I notice everything. I've never noticed it before because my typical driving is around town at slow speeds, but I'll be damned if I didn't notice it. That totally pissed me off. And finding out today that I was able to put an entire quart of rear diff fluid in without it even running out the fill hole has got my blood pressure boiling. I hate noises especially driveline noises. That extra quart had better quiet that rear diff down. This issue should never have even been an issue. I'm a little pissed as you can tell. Breathe Dale....breathe....lol....this is stuff that gets my blood boiling because it's so stupid.

the8rotor · May 4, 2023

12 minutes ago, Jettech1 said:

It is for sure. And there's one thing I haven't mentioned that I noticed a few days ago when going 80mph on I-85 north that has me totally pissed now. I started to notice a slight driveline whine at those speeds. My truck is so quiet I notice everything. I've never noticed it before because my typical driving is around town at slow speeds, but I'll be damned if I didn't notice it. That totally pissed me off. And finding out today that I was able to put an entire quart of rear diff fluid in without it even running out the fill hole has got my blood pressure boiling. I hate noises especially driveline noises. That extra quart had better quiet that rear diff down. This issue should never have even been an issue. I'm a little pissed as you can tell. Breathe Dale....breathe....lol....this is stuff that gets my blood boiling because it's so stupid.

Totally understand your frustration. Beyond unacceptable and I'd be boiling if I were you as well. Such an easily avoidable problem.

Really makes me wonder what the percentage of hd trucks on the road are low?

Jettech1 · May 4, 2023

5 minutes ago, the8rotor said:

Totally understand your frustration. Beyond unacceptable and I'd be boiling if I were you as well. Such an easily avoidable problem.

Really makes me wonder what the percentage of hd trucks on the road are low?

Great question. From what I'm reading most of them!! I have 8400 miles on my truck now and that extra oil had better solve that noise at high speeds. Tomorrow is a recheck of the rear diff and a new check on my front. I hope the front one is all good and that extra quart brought me up to at least a half inch of the fill hole on the rear. We will see.

My gloves got wet with oil and the rag I had wasn't doing much for me at the time so I slammed the bolt back into the cover plate and called it a day. I will not stick my bare finger in hypoid oil, getting that stench off your fingers can take days.....lol....and hopefully no one takes it from there ok? Let's keep this PG rated and family friendly all....lol....get some aircraft fuel on your hands or clothes. Burn them....lol....well not your fingers...lol...

Edited May 4, 2023 by Jettech1

Grumpy Bear · May 4, 2023

2 hours ago, Jettech1 said:

Here's something else I've been wondering and hoping @newdude or another person that knows the answer can chime in. Because I live in Atlanta and it rarely goes below freezing during the winter and is basically hot as hell for many months, would it be a recommended choice to install 75-140 synthetic LS gear oil in the rear diff? I'm just wondering if it would mess with the LS portion of the rear diff if I did or would it work fine for the climate I live in?

Edit: do these rear diffs use clutch packs for the LS or the conical version?

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.

Edited May 4, 2023 by Grumpy Bear

Jettech1 · May 4, 2023

5 minutes 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.

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?