Chassis lube - Chevy Express

markopolo · 03-18-2007, 12:04 AM

I went to a drive through oil change franchise today and asked that they lube the chassis.

Their computer said there were 12 lube points on my Chevy Express.

Anyone know if that's right?

In addition to the oil change I had the oil in the differential changed - they always up-sell me on something.

bobojay · 03-18-2007, 08:08 AM

Marco, you want to know about Chevy/GM, just ask me. I'm a GM geek, (besides working for them for 34 years). I'll do the best I can to answer the question.

The grease job zerk fitting number is about right. It should say or show the spots in your owners manual. You should be able to do this very easy maintenance item. Just takes a grease gun and some cheap rags.

The differential: Is yours a posi-trac? Does it have the G-80 option code. If it does, it's a posi. The diff fluid should have been changed initially at 5000mi. Then unless you tow regularly, at 75,000mi. It should have a good synthetic 75w-90 weight gear lube installed with either a G-80 or standard diff. Towing alot, it should be changed at 50,000mi intervals. Check your lube shop invoice to see what they used.

The trans. I wouldn't worry about until 50-60,000mi. unless you tow alot. You have a 4L80-E trans. The heaviest duty Hydramatic GM makes. There's one heavier duty, light duty truck trans. in GM's stable and it's the Allison 1000 5 & 6 spd. auto. It's used in GM's light & medium duty pickups with the 8.1 gas and the Duramax 6.6 diesel engines.
There's a new Hydramatic 6 spd. auto in a few current GM light dutys, but I won't get into it because it'll confuse you more.

Hope this helps a bit..........

markopolo · 03-18-2007, 04:07 PM

Thanks for the info

They used Esso Gear Oil LS 80W-90 GL-5 for the differential.

You're right about what's in the manual:

SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 12378261, in Canada 10953455) or equivalent meeting GM Specification 9986115.

Would you change it out or leave it if it was your van?

I'm going to try to get an appointment at a GM dealer next week to have them check the transmission seals. The oil change place said it was leaking. (I also noticed oil on the ground where I park it)

I don't know if it is posi-trac. How can I find out? Where would I see the G-80 option code.

I do know that it came with "Locking differential & external transmission cooler".

bobojay · 03-18-2007, 05:44 PM

Check your passenger side front door rear edge. You should see a sticker with the codes. There will be many codes. They are almost all 3 digit codes in letters and numbers. They will be in alphabetical order.
G80 is the code for locking differential. If it doesn't have the G80 code it doesn't have the locker.
I thought all RT Chevys had the external trans. cooler and locker. At least since 2003.

If it was me, I'd make sure what they put in was synthetic. If not, go get your money back for that service since they didn't put the "required" fluid in, and I'd get it out of there before the next trip for sure.
Personally, I don't go near quick lube places or Wal Mart lubes. I've heard too many horror stories!
If I can help any more don't hesitate to ask.........

bobojay · 03-18-2007, 05:47 PM

My bad......I'm using the terms positrac and locking diff. GM's correct term is locking differential.
You've got G80 if you've got locking differential.

bobojay · 03-19-2007, 06:06 AM

Marco, one place where RT does a better job than PW in my opinion is the basic van from GM.

PW doesn't buy theirs with rear window defog, Locking diff, 4:10 gear or external trans cooler. I wish ours had all of the above. I feel that it's just that extra few things that makes the van more appropriate for heavier duty use.

PW orders theirs with the 3:73 axle. Fewer rpm's at highway speed, about 500 less at 60mph, maybe a slight bit better fuel mileage at the sacrifice of less low speed acceleration and more downshifting, (gear hunting), of the transmission at medium and highway speeds when encountering a slight hill. This last item just drives me crazy sometimes on highway trips. Up, Down, up, down the transmission goes in uneven terrain driving.

markopolo · 03-19-2007, 02:21 PM

I think the locking diff., 4:10 gear & external trans cooler became standard on Roadtreks in 2005.

It was optional on the 2004 model year.

I figured the 4:10 was mainly for towing and thought the 3:73 would save $$$ on fuel. I never thought about it downshifting more.

bobojay · 03-19-2007, 04:37 PM

Quote:

Originally Posted by markopolo

I think the locking diff., 4:10 gear & external trans cooler became standard on Roadtreks in 2005.

It was optional on the 2004 model year.

I figured the 4:10 was mainly for towing and thought the 3:73 would save $$$ on fuel. I never thought about it downshifting more.

Oh yeah! The Chevy pickup we had as a tow vehicle for our 5th wheel was the same way, especially when towing. They even had a software upgrade on that particular truck, both 8.1 gas and Duramax diesel to help cut down on that situation.

I made the mistake of ordering it with 3:73 vs 4:10. Now 4:10 is not going to eliminate the situation, but it sure will help cut down on it. Besides giving you better off line acceleration.

markopolo · 03-21-2007, 12:08 AM

I called the lube place re: the differential oil and they said to bring it back and they'll change it. - thanks for pointing that out bobojay.

I'm going to a Chevy dealer this week to get the transmission seals checked.

bobojay · 03-21-2007, 03:59 AM

Good. Like to help fellow GM owners...........

markopolo · 03-22-2007, 07:20 PM

GM dealer is changing the differential oil today.

Franchise lube shop has agreed to pay for it and they are giving me a coupon for a free synthetic oil change for the motor to use at a later date.

They were really good about it. Mistakes happen. I think it's really great that they are willing to do what it takes to make this right.

bobojay · 03-23-2007, 07:02 AM

Good deal. What was your trans leak?

I've used synthetic oil, (Amsoil), in my entire vehicle(s) since 1989. Can't say enough about them and their products.
I change my oil twice a year. Once in the spring, and once in the fall. Usually about March 1st and Sept. 1st or so. I wouldn't do this if I was using regular motor oil. Never have had a problem on any of my engines. The highest mileage one was at 143,000 when we traded it, ('92 Chevrolet Lumina).

markopolo · 03-23-2007, 01:53 PM

The GM dealer is replacing a transmission seal under warranty. I never had to add transmission fluid but it did stain the drive way where it is parked. It should be fixed today. They had to order the seal.

Barman · 03-29-2007, 02:21 AM

On our 2006 190 Versatile the locking rear differential and 4:10 rear gears were still optional, and we ordered them. We very rarely ever have a transmission shift even in the mountains. I put the cruise on 65 MPH and it goes up and down the hills with ease. It is so rare to feel it shift, that when it is so steep that it does shift my wife and I look at each other in surprise. Even with the 4:10 gears we average 14 to 16 MPG and occasionally get 17 to 19 MPG. We also are using the Amsoil synthetics, and have for many years. We just sold a car with almost 300,000 miles on it, and it consumed no oil between the 25,000 mile oil change intervals. It really is a product that will protect our sizeable investments in our class Bs.

bobojay · 03-29-2007, 03:08 AM

That's good news to hear about your history with Amsoil. I swear by it after using it for so many years & miles.
Being an Amsoil dealer, it kinda makes me feel like I'm being backed up by real life statistics.

It's going in our new B as soon as it passes 3000mi.....

Barman · 03-29-2007, 01:28 PM

Ours got all the Amsoil treatment at about 3500 miles. The rear differential got it even sooner. Happy travelin!

bobojay · 03-30-2007, 06:26 AM

GM's new recommendation on their HD pickups is to wait till 5000mi to change the rear gear lube. I'll do that before I'll change it, give it a good flush out, then put 75w-90 severe gear in it.

Ron J. Moore · 04-28-2007, 01:38 AM

Mark & Bob, you should enjoy this input - my first oil change was at a Jiffy Lube (physical problems prevent me doing now) and they said I had 6!! Thinking this strange, I found a GM Website where you provide them your VIN, year, etc and they will answer your question(s). They came back with a "da, they didn't know because they could be different at each place they are assembled or something to that effect. While in FL this winter my "Change Oil" light came on - went into a J/L and they put on the paper that this vehicle has "sealed or permanent fittings." I have since found out, and you guys confirm - there are 12!!! The Owner's Manual doesn't show any schematic of where they are, but I am about to find out for myself shortly. Just thought I'd brighten up our days. Ron

Ron & Dot Moore
05/04 RT 190P
FMCA 360521

markopolo · 04-28-2007, 03:07 AM

You bring up a good point. So many vehicles have sealed bearings. The fast lube places are convenient but they really rely on their computers. We have to make sure to tell them what we need.

Bob helped me out when he pointed out my van should have a synthetic 75w-90. I was very surprised that the fast lube place didn't put the right stuff in.

I wonder if they wipe the zerk fitting first?

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