Chevrolet Suburban 3500 Questions

[Bigburb3500]

Unfortunately news everyone… although the dipstick might work on the 6L90, it does not fit behind the 6.0 on the K2 body… I have been fighting and negotiation for well over an hr and I cannot seem to get enough room to get it in place. I had to remove plug 8 to get it that far but it just won’t go…. Maybe from the bottom? But would need a lift at that point and I unfortunately do not have that equipment.

 

[Geotrash]

Unfortunately news everyone… although the dipstick might work on the 6L90, it does not fit behind the 6.0 on the K2 body… I have been fighting and negotiation for well over an hr and I cannot seem to get enough room to get it in place. I had to remove plug 8 to get it that far but it just won’t go…. Maybe from the bottom? But would need a lift at that point and I unfortunately do not have that equipment.

Well, shit.

I wonder if the dipstick tube from a K2 with a 6L80 might do the trick?

Edit: nvm - none of them had one.

Edit again: The 2015 with the 6L80 did! https://www.rockauto.com/en/moreinfo.php?pk=6355269&cc=3307626&pt=49580&jsn=807

 

[Bigburb3500]

Well, shit.

I wonder if the dipstick tube from a K2 with a 6L80 might do the trick?

Edit: nvm - none of them had one.

Edit again: The 2015 with the 6L80 did! https://www.rockauto.com/en/moreinfo.php?pk=6355269&cc=3307626&pt=49580&jsn=807

Likely will fit and be able to be attached but will not be the correct depth/length?

 

[Geotrash]

Likely will fit and be able to be attached but will not be the correct depth/length?

Hard to say. I think the 6L80 is the same dimensionally to that point. I think it's the housing to the rear of the dipstick that's longer. I may give it a try.

 

[Geotrash]

Do any of y'all know off hand if the 3500HD uses the same A/C condenser setup as the 1500's? I'm asking because they've been problematic and I want to be prepared with the equipment I need should I have to replace it at some point.

 

[1TONSUB]

Unfortunately news everyone… although the dipstick might work on the 6L90, it does not fit behind the 6.0 on the K2 body… I have been fighting and negotiation for well over an hr and I cannot seem to get enough room to get it in place. I had to remove plug 8 to get it that far but it just won’t go…. Maybe from the bottom? But would need a lift at that point and I unfortunately do not have that equipment.

Sorry man that sucks. Appreciate you being the front runner and guinea pig so to speak. I wonder if that's why the aftermarket (like my link above) ones use flex tube.

 

[Geotrash]

Regarding A/C, the plot thickens:

Yup, you read that right. The Suburban 3500 HD uses R-134a, when all of the other Suburbans of this vintage use the curiously flammable R-1234yf.

 

[1TONSUB]

Regarding A/C, the plot thickens:

View attachment 458804

Yup, you read that right. The Suburban 3500 HD uses R-134a, when all of the other Suburbans of this vintage use the curiously flammable R-1234yf.

So that means we are less likely to have failures? Sorry not aware of this issue yet. I thought I heard there are some known issue with the fitting by condenser leaking.

 

[89Suburban]

Regarding A/C, the plot thickens:

View attachment 458804

Yup, you read that right. The Suburban 3500 HD uses R-134a, when all of the other Suburbans of this vintage use the curiously flammable R-1234yf.

Well look at you fancy pants lol.

 

[Geotrash]

So that means we are less likely to have failures?

That's what I'm trying to figure. If it uses the same condenser design as the 1500 'burbs, then I reckon at some point in the next 30K miles I'm liable to be getting a blast of the devil's flatus because it's going to happen when we're in the middle of a 3,000 mile camping trip in July with a schedule to keep. Did I mention that one of the reasons my wife divorced her first husband is that he was so cheap he squeaked when he walked, which meant she once spent a whole summer commuting in the jungle heat of Virginia with broken A/C in her car? I gotta get to the bottom of this, gents - my marriage may well depend on it.

Sorry not aware of this issue yet. I thought I heard there are some known issue with the fitting by condenser leaking.

Yeah. Found this image in an old thread of the infamous spot. I s'pose GM's lucky that with the flammable refrigerant none of them turned into Roman candles. Anyway, I'll shove my schnoz in there later this afternoon and see if mine looks anything like this one.

 

[Bigburb3500]

Sorry man that sucks. Appreciate you being the front runner and guinea pig so to speak. I wonder if that's why the aftermarket (like my link above) ones use flex tube.

Could be? The issue is the 6.0 is just a LITTLE too big around the backside. Who ever thought that would be an issue?

Now I have to figure out what to do with the dipstick and tube… well, guess it will be in the back corner of the garage till my child is cleaning out the house in 60yrs

 

[Geotrash]

Pulled the camper out to Elkton, VA for the weekend and dropped it off at our camping spot, then Saturday morning had to drive back to Richmond for our daughter's volleyball tournament. Then out to Luray for our good friends' grand opening on their new wedding venue Saturday afternoon. Then back to Elkton to spend the night, and finally pulled the camper back home on Sunday afternoon. About 8 hours behind the wheel, all in.

Pulling the camper, we took route 33 crossing the Skyline Drive, as we often do. Outside temp was was 87º for the climb on the outbound leg, and the transmission topped out around 190 while the engine coolant temp gauge never moved. Last time I pulled the camper with our 2012 Yukon XL Denali over that route in similar temps, I saw 235 on the transmission and 230 or so on the coolant, so the Suburban 3500 runs significantly cooler when towing.

The other good news is I finally got some unloaded highway miles on with the new wheels and tires and registered 17.9 on average from Charlottesville, to Richmond, driving at 70 mph on I-64. It was a calm wind day so that effect should be negligible. But I got 17.7 on the way back out to Charlottesville, probably owing to the fact that it's slightly uphill westbound vs eastbound as the route climbs up toward the Piedmont of the Blue Ridge.

The bummer was that my wife started to get tired of the rough ride of the 3500 on our way home Sunday, so I may need to look into Suburban 2500 springs and torsion bars soon.

Unloaded mpg after 50 miles on the highway at 70 mph:

 

[Bigburb3500]

Pulled the camper out to Elkton, VA for the weekend and dropped it off at our camping spot, then Saturday morning had to drive back to Richmond for our daughter's volleyball tournament. Then out to Luray for our good friends' grand opening on their new wedding venue Saturday afternoon. Then back to Elkton to spend the night, and finally pulled the camper back home on Sunday afternoon. About 8 hours behind the wheel, all in.

Pulling the camper, we took route 33 crossing the Skyline Drive, as we often do. Outside temp was was 87º for the climb on the outbound leg, and the transmission topped out around 190 while the engine coolant temp gauge never moved. Last time I pulled the camper with our 2012 Yukon XL Denali over that route in similar temps, I saw 235 on the transmission and 230 or so on the coolant, so the Suburban 3500 runs significantly cooler when towing.

The other good news is I finally got some unloaded highway miles on with the new wheels and tires and registered 17.9 on average from Charlottesville, to Richmond, driving at 70 mph on I-64. It was a calm wind day so that effect should be negligible. But I got 17.7 on the way back out to Charlottesville, probably owing to the fact that it's slightly uphill westbound vs eastbound as the route climbs up toward the Piedmont of the Blue Ridge.

The bummer was that my wife started to get tired of the rough ride of the 3500 on our way hoe Sunday, so I may need to look into Suburban 2500 springs and torsion bars soon.

Unloaded mpg after 50 miles on the highway at 70 mph:
View attachment 459317
View attachment 459319
View attachment 459322
View attachment 459320
View attachment 459324

Wow! That awesome! I usually see around 15… maybe 16 if I’m lucky. My trans temp is hovering around 170ish during normal driving but since replacing the fluid and driving 100 miles at 80mph with ambient temp 85° it stabilizes at 165°

 

[Geotrash]

Wow! That awesome! I usually see around 15… maybe 16 if I’m lucky. My trans temp is hovering around 170ish during normal driving but since replacing the fluid and driving 100 miles at 80mph with ambient temp 85° it stabilizes at 165°

That’s about what I see for transmission temperature as well, when I’m not towing. Perfect.

 

[TripleFJeff]

On a road trip in my '08 2500 from Philadelphia area to Seattle, WA (then back). Caught a pair of armored 3500's in the wild. Just off I90 in Blue Earth, MN. My white 2500 with the photobomb on the left...

 

[Marky Dissod]

On a road trip in my '08 2500 from Philadelphia area to Seattle, WA (then back). Caught a pair of armored 3500s in the wild just off I90 in Blue Earth, MN.
My white 2500 with the photobomb on the left...View attachment 459360View attachment 459361

By now I'm sure it's been noticed that the GMT900-1500 mirror housings are being used by the GMTK2YC 3500.

 

[Geotrash]

By now I'm sure it's been noticed that the GMT900-1500 mirror housings are being used by the GMTK2YC 3500.

Yes. And the factory pax side mirror glass is flat instead of convex, so I had to buy a replacement glass from Amazon to correct that issue. But the good news is the snap on tow mirrors from my 2012 Yukon XL fit perfectly.

 

[Geotrash]

We are currently on a camping trip extending over 2000 miles around the great lakes, and it’s becoming increasingly apparent that I’m going to need to make some suspension changes. I’ve read that the leaf springs and torsion bars for the 2500 suburbans will fit these and provide a better ride. The main problem I am trying to solve is stiffness and chucking over rough pavement and concrete on the interstates when towing. Yes, I know it’s a heavy duty truck, but I’m sure some headway could be made. Anyone know of anyone else with a 3500 who has tried this upgrade?

 

[TripleFJeff]

We are currently on a camping trip extending over 2000 miles around the great lakes, and it’s becoming increasingly apparent that I’m going to need to make some suspension changes. I’ve read that the leaf springs and torsion bars for the 2500 suburbans will fit these and provide a better ride. The main problem I am trying to solve is stiffness and chucking over rough pavement and concrete on the interstates when towing. Yes, I know it’s a heavy duty truck, but I’m sure some headway could be made. Anyone know of anyone else with a 3500 who has tried this upgrade?

What tires, and do you have stock shocks on it? Bilsteins made a world of difference on my 2500, as did going from the OE Bridgestone Duravis to Michelin Defender LTXs. When those where done I went to the newer LTX2 and they are even better.

 

[Geotrash]

What tires, and do you have stock shocks on it? Bilsteins made a world of difference on my 2500, as did going from the OE Bridgestone Duravis to Michelin Defender LTXs. When those were done I went to the newer LTX2 and they are even better.

That’s good to know, thank you. Tires are Michelin Agilis CrossClimate set to 50 front and 60 rear. Stock shocks. I’ll try the Bilstein’s next.