Chevrolet Suburban 3500 Questions

[Bigburb3500]

Another thought came to mind - and again I got this from the Duraburb video ( you might want to go search that out): If I remember correctly Duraburb said that the Suburban 3500 had the "new" style 8 lug circle of 180mm or whatever it is. The "old" lug circle was like 8x 6.5" or something like that. That *might* mean that the upper A-arms are indeed different than anything else because they're adapting from the holdover 2500 frame - to the spindles that work with hubs for the 8x180mm bolt circle or something like that. I don't know - I'm just guessing. But - again - that might not mean that the upper A-arms are actually any different than say A-arms from the earlier 2500 Suburban/Yukon/Sierra/Silverado - it could just be that the ball joint is different than the "old" ball joint - so the A-arm is the same - but the ball joint is different. Again - don't know - I'm just guessing.

What you probably need to do is take some measurements or match up your upper A-arms - with an A-arm from an older truck - and see if they're the same. I might have my old one's still hanging around somewhere - I'd have to go look. You might also be able to get some measurements from a place like Cognito - to see if they'd match up. Sometimes places like that are willing to work with you - just because it gives them info they can apply towards their product line.

So I have watched Duraburbs videos… a few too many times lol.

I will likely reach out to Cognito, but several places I have talked to already have admitted they have not had testing on the 3500 which keeps them from offering any sort of “guarantee” which is a little frustrating because if something doesn’t fit/work I’m stuck with an expensive paper weight.

 

[calsdad]

So I have watched Duraburbs videos… a few too many times lol.

I will likely reach out to Cognito, but several places I have talked to already have admitted they have not had testing on the 3500 which keeps them from offering any sort of “guarantee” which is a little frustrating because if something doesn’t fit/work I’m stuck with an expensive paper weight.

If I get a chance - I'll look around and see if I saved the old control arms off my Yukon when I changed them over to the Cognito upper arms. Sometimes I save stuff like that just in case I think I might need them later for a rebuild , sometimes I toss the stuff out because I've got too much junk hanging around already. I really don't remember if I saved them.

 

[Bigburb3500]

If I get a chance - I'll look around and see if I saved the old control arms off my Yukon when I changed them over to the Cognito upper arms. Sometimes I save stuff like that just in case I think I might need them later for a rebuild , sometimes I toss the stuff out because I've got too much junk hanging around already. I really don't remember if I saved them.

I get told I’m not allowed to keep spare parts after two years if I do not touch them… that’s why I move stuff each year… then can’t find it on yr 3 when I need it.

 

[Geotrash]

Alright, so to all of you watching this thread, I’m CONTEMPLATING doing a small lift and a few other things. One item that I think I should do with the lift is add new upper control arms. The issue here is these appear to be that the Suburban 3500 has specific control arms… I find that nearly impossible to believe given how GM loves parts sharing. Can someone help me cross reference this and see if there is an aftermarket control arm that would work?

https://g.oempartsonline.com/oem-parts/gm-front-upper-control-arm-23324185

A tip I learned from a private conversation with another Suburban 3500 owner is that the leaf springs and front torsion bars from the older Suburban 2500's (e.g. GMT900 version) will fit the K2xx Suburban 3500's and offer a slightly more compliant ride. I'm not going to do that because I'm happy with the ride in mine, and because I really only use it fully loaded with people and gear while towing a camper. But it's an option to consider with yours being a daily driver.

 

[Geotrash]

Nice new video on the armored versions of these trucks, including the latest iteration, from Jay Leno's Garage:

 

[Geotrash]

For future readers of this thread (hopefully some more 3500 owners will come along, too!), the factory tire size is 265/70r17. But 275/65r18 fits great. They're a half inch bigger in both diameter and width, but they fit fine with no rubbing. The factory wheel offset is +44, which matches the factory offset for most newer GM pickups with the 8x180 bolt pattern. Lots of good deals out there on OEM 18" wheels in different styles. I've only had them on for a few days, but the ride is unchanged with the 18" tires, as far as I can tell.

 

[Bigburb3500]

A tip I learned from a private conversation with another Suburban 3500 owner is that the leaf springs and front torsion bars from the older Suburban 2500's (e.g. GMT900 version) will fit the K2xx Suburban 3500's and offer a slightly more compliant ride. I'm not going to do that because I'm happy with the ride in mine, and because I really only use it fully loaded with people and gear while towing a camper. But it's an option to consider with yours being a daily driver.

I will pass on this as well as the ride is more than compliant for me as well.

 

[calsdad]

My 2010 2500 Yukon XL has had a banging noise in the front for a while. I can't track it down. I thought that it might be something to do with the front swaybar - so a couple of months ago I just took the swaybar off to see if the noise would go away. Figured I could drive it for a while and see what happened.

Well the truck has a much nicer ride - without that front swaybar. The roads around here suck - especially this winter because we've had a lot of freeze-thaw cycles. I haven't noticed any real downside to the swaybar not being there either. The truck seems to handle just fine. Really has me thinking that if the truck really needs the roll stiffness - that instead of the swaybar I'll just add some slightly stiffer torsion bars.

 

[Bigburb3500]

My 2010 2500 Yukon XL has had a banging noise in the front for a while. I can't track it down. I thought that it might be something to do with the front swaybar - so a couple of months ago I just took the swaybar off to see if the noise would go away. Figured I could drive it for a while and see what happened.

Well the truck has a much nicer ride - without that front swaybar. The roads around here suck - especially this winter because we've had a lot of freeze-thaw cycles. I haven't noticed any real downside to the swaybar not being there either. The truck seems to handle just fine. Really has me thinking that if the truck really needs the roll stiffness - that instead of the swaybar I'll just add some slightly stiffer torsion bars.

If you are not doing much highway driving I may agree with you, but if you are on the highway at all I would probably recommend putting it back on. These are all big trucks and going 60+ and IF you had to do any sort of evasive maneuver the away bar is what keeps the truck controllable.

 

[calsdad]

If you are not doing much highway driving I may agree with you, but if you are on the highway at all I would probably recommend putting it back on. These are all big trucks and going 60+ and IF you had to do any sort of evasive maneuver the away bar is what keeps the truck controllable.

Well actually it's roll stiffness that keeps the truck controllable. And you can do roll stiffness other ways as well. I used to do a bunch of autocross when I was younger and there's always a debate in suspension tuning about whether you go with sway bars - or with increased spring stiffness. Each has their own drawbacks and advantages. After driving the truck this way - and I have driven it on the highway - and it seems fine .. I wonder if it might be better to maybe add some more roll stiffness into it with stiffer torsion bars and maybe the addition of some of those Timken load things. (forget what they're called). For the time being it's an interesting experiment.

 

[Geotrash]

Well actually it's roll stiffness that keeps the truck controllable. And you can do roll stiffness other ways as well. I used to do a bunch of autocross when I was younger and there's always a debate in suspension tuning about whether you go with sway bars - or with increased spring stiffness. Each has their own drawbacks and advantages. After driving the truck this way - and I have driven it on the highway - and it seems fine .. I wonder if it might be better to maybe add some more roll stiffness into it with stiffer torsion bars and maybe the addition of some of those Timken load things. (forget what they're called). For the time being it's an interesting experiment.

You could always try the torsion bars and leaf springs from the Suburban 3500.

One truism I’ve found over the years is that manufacturers are never going to waste money on parts that an engineer could reasonably argue they don’t need. If GM could’ve achieved the ride and handling goals they were targeting with simply stiffening the springs, they would have. My bet is that they know something about the handling of these in certain circumstances, that we don’t, that caused them to spend the additional money to add the sway bar.

 

[Geotrash]

For those not following my build thread, I learned from another 3500 owner what the correct hitch is for these if you want to go to a Class V:

Xtra Duty Class 5 Hitch, 2" Receiver, Select Escalade, Suburban, Tahoe, Yukon

Hauling heavy-duty equipment to that next big job? Towing your yacht out to the lake for another weekend on the water? Bringing some livestock home to the farm from the county auction? Whatever towing hurdle you need to overcome, make it look easy with CURT. CURT Xtra Duty class 5 trailer...

www.curtmfg.com

Picked up one from a local guy on FB today. He had a Suburban 3500 but sold it a couple of years ago. $100, delivered to the Wawa close to my house this afternoon. Heckuva deal.

It’s a bolt in replacement for the factory Class IV hitch but as you can see, it lacks the holes for the electrical socket and the spare tire hoist.

 

[Slatinaa]

Hello All, recently purchased 16 Suburban 3500 LS. It was a homeland security vehicle. Wire under radio dash is cut. Everything works as it should except the USBs below radio and in the jump seat.

Does anyone have a photo of what this is to look like or know what this goes to?

I have searched this forum and the web but can not find dash and consul or jump seat wiring diagram.

Please help. Thank you all.

 

[Bigburb3500]

Welcome! To one small little obscure corner of the internet where we now have a whopping 3 members part of the 3500 owners group! I will be able to check this later this evening and post a picture. Where under the dash is this?

Hello All, recently purchased 16 Suburban 3500 LS. It was a homeland security vehicle. Wire under radio dash is cut. Everything works as it should except the USBs below radio and in the jump seat.

Does anyone have a photo of what this is to look like or know what this goes to?

I have searched this forum and the web but can not find dash and consul or jump seat wiring diagram.

Please help. Thank you all.

 

[Geotrash]

Hello All, recently purchased 16 Suburban 3500 LS. It was a homeland security vehicle. Wire under radio dash is cut. Everything works as it should except the USBs below radio and in the jump seat.

Does anyone have a photo of what this is to look like or know what this goes to?

I have searched this forum and the web but can not find dash and consul or jump seat wiring diagram.

Please help. Thank you all.

Welcome to the family! Looks awesome! I have an alldatadiy subscription for mine (highly recommended) and there are complete wiring diagrams there. I don't have any photos of that area in mine because I haven't removed those pieces. Might also want to check the GM up-fitters manual.

Anyway, here's the schematic for the 2018 Suburban 3500.

 

[Slatinaa]

Hello All, recently purchased 16 Suburban 3500 LS. It was a homeland security vehicle. Wire under radio dash is cut. Everything works as it should except the USBs below radio and in the jump seat.

Does anyone have a photo of what this is to look like or know what this goes to?

I have searched this forum and the web but can not find dash and consul or jump seat wiring diagram.

Please help. Thank you all.

Welcome! To one small little obscure corner of the internet where we now have a whopping 3 members part of the 3500 owners group! I will be able to check this later this evening and post a picture. Where under the dash is this?

Hello Bigburb3500, appreciate your help with this. Thanks for the welcome.

Its located right under the center left. Under the drivers temp control knob close to floor.
See attached photo with red arrow.

 

[Bigburb3500]

Ok, I might not be able to check tonight as I have a full center console, and I may have to open a panel to see this area.

 

[Slatinaa]

Welcome to the family! Looks awesome! I have an alldatadiy subscription for mine (highly recommended) and there are complete wiring diagrams there. I don't have any photos of that area in mine because I haven't removed those pieces. Might also want to check the GM up-fitters manual.

Anyway, here's the schematic for the 2018 Suburban 3500.

View attachment 452718

Thank you

Welcome to the family! Looks awesome! I have an alldatadiy subscription for mine (highly recommended) and there are complete wiring diagrams there. I don't have any photos of that area in mine because I haven't removed those pieces. Might also want to check the GM up-fitters manual.

Anyway, here's the schematic for the 2018 Suburban 3500.

View attachment 452718

Thank you Geotrash!
The Jump Seats wiring that I have needs to go to under the center console where the wires are cut. Need to figure out wiring from my Jump seat plug/connector to the cut wire that probably had a plug/connector.

Attached photos of cut wires below center console and jump seat harness that probably needs to go to front where wires are cut.

 

[Geotrash]

Thank you

Thank you Geotrash!
The Jump Seats wiring that I have needs to go to under the center console where the wires are cut. Need to figure out wiring from my Jump seat plug/connector to the cut wire that probably had a plug/connector.

Attached photos of cut wires below center console and jump seat harness that probably needs to go to front where wires are cut.

Next step will be to unwind some of that electrical tape and sheathing around the cut wires so you can get a good look at the wire colors. Compare those to the schematic I posted and you can probably start piecing things back together.

 

[Geotrash]

Also, note that this looks like a mini usb connector. My guess is it originally went to the USB outlet at the back of the center console.