Chevrolet Suburban 3500 Questions

[Geotrash]

I’m interested to see what your thoughts are when you swap back into your 1/2 ton SUV. I know you saw it’s night and day but curious how big of a difference going backwards is and if you “forgot” how much more you worked the truck.

I've pulled the camper with our 2012 Yukon XL Denali a few times in the last year since buying the 3500. Often it's just taking it to/from the storage yard, but I also used it for a camping trip in January when we were expecting snow and thought we might encounter some road salt. The 1500 pulls the camper just fine with that 6.2, but the 3.42 gears mean I spend most of my time in 4th on the highway and occasionally 5th, whereas the 3500 likes to stay in 6th and occasionally downshift to 5th. Basically, the 3500 can hold 6th significantly longer than the 1500 can hold 5th on the same stretches of highway, thanks to its 4.10 gears.

The rear suspension on the 1500 also has to work much harder. The softer spring rate means that it relies on the factory air bags on the shocks to take up the squat, whereas the 3500 doesn't squat. The ride in the 1500 while towing is cushier but the trailer sway is more pronounced as well, with the 3500 being considerably steadier due to its suspension stiffness and additional weight. And with the Bilstein 4600 shocks now, the 3500's ride when towing has gotten much closer to the enjoyableness of the 1500's ride.

 

[Bigburb3500]

I've pulled the camper with our 2012 Yukon XL Denali a few times in the last year since buying the 3500. Often it's just taking it to/from the storage yard, but I also used it for a camping trip in January when we were expecting snow and thought we might encounter some road salt. The 1500 pulls the camper just fine with that 6.2, but the 3.42 gears mean I spend most of my time in 4th on the highway and occasionally 5th, whereas the 3500 likes to stay in 6th and occasionally downshift to 5th. Basically, the 3500 can hold 6th significantly longer than the 1500 can hold 5th on the same stretches of highway, thanks to its 4.10 gears.

The rear suspension on the 1500 also has to work much harder. The softer spring rate means that it relies on the factory air bags on the shocks to take up the squat, whereas the 3500 doesn't squat. The ride in the 1500 while towing is cushier but the trailer sway is more pronounced as well, with the 3500 being considerably steadier due to its suspension stiffness and additional weight. And with the Bilstein 4600 shocks now, the 3500's ride when towing has gotten much closer to the enjoyableness of the 1500's ride.

No one can say that 1) There are no towing reviews of a 3500 and 2) That the 1-ton community here is non-participatory

Btw have you put one the new heavier duty receiver yet?

 

[Geotrash]

No one can say that 1) There are no towing reviews of a 3500 and 2) That the 1-ton community here is non-participatory

Btw have you put one the new heavier duty receiver yet?

No, but I see that the guys over at Duramax Specialties have designed a frame brace for the factory hitch to address the frame bending/hitch droop problem that some of their Duramax-converted 3/4 ton Suburbans have encountered when towing heavy with the factory hitch. I have a Curt class V hitch for the GMT800 2500 suburban but it would require modifying the plastic bumper fascia and spare tire hoist to install it on the 2018 3500.

So, I think I’ll wait for the Duramax Specialties guys to put their brace in production and go that route. It’s a bolt-on solution, too.

 

[Bigburb3500]

No, but I see that the guys over at Duramax Specialties have designed a frame brace for the factory hitch to address the frame bending/hitch droop problem that some of their Duramax-converted 3/4 ton Suburbans have encountered when towing heavy with the factory hitch. I have a Curt class V hitch for the GMT800 2500 suburban but it would require modifying the plastic bumper fascia and spare tire hoist to install it on the 2018 3500.

So, I think I’ll wait for the Duramax Specialties guys to put their brace in production and go that route. It’s a bolt-on solution, too.

Send me that link and I might be signing up for that as well! We are looking at a 12-15k lb boat purchase in the near future - we will NOT be towing much but rather have a trailer to haul out for maintenance.

 

[Geotrash]

Send me that link and I might be signing up for that as well! We are looking at a 12-15k lb boat purchase in the near future - we will NOT be towing much but rather have a trailer to haul out for maintenance.

Here you go: https://www.facebook.com/share/p/14PRDNQXwvm/

Sounds like a sweet boat! Send pics when the time comes!

 

[Bigburb3500]

Here you go: https://www.facebook.com/share/p/14PRDNQXwvm/

Sounds like a sweet boat! Send pics when the time comes!

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Ohh that’s beefy… I would order one.

Will do! I got caught almost pulling the trigger the other day lol

 

[Geotrash]

I’m in need of a front hitch for the 3500 burb and the folks on the interwebz with GMT900 2500’s who know things, say this is the one to get. So I’m going to try it and let you know. Airstreams aren’t known for exterior storage so I need a place to haul the Predator 3500 when we boondock. It will double for bike hauling when needed too.

https://www.etrailer.com/Front-Receiver-Hitch/Draw~Tite/DT57MR.html?hhyear=2018&hhmake=Chevrolet&hhmodel=Suburban

 

[Bigburb3500]

I’m in need of a front hitch for the 3500 burb and the folks on the interwebz with GMT900 2500’s who know things, say this is the one to get. So I’m going to try it and let you know. Airstreams aren’t known for exterior storage so I need a place to haul the Predator 3500 when we boondock. It will double for bike hauling when needed too.

https://www.etrailer.com/Front-Receiver-Hitch/Draw~Tite/DT57MR.html?hhyear=2018&hhmake=Chevrolet&hhmodel=Suburban

I’m curious if it will work because I thought the frame was pretty similar to the 3/4 tons Sub so I would have initially shopped for a 2013 Suburban 2500 front hitch?

 

[Geotrash]

I’m curious if it will work because I thought the frame was pretty similar to the 3/4 tons Sub so I would have initially shopped for a 2013 Suburban 2500 front hitch?

Yup. The guy I found out about it from installed it on a 2013 Suburban 2500 and says it works.

 

[Bigburb3500]

Here you go: https://www.facebook.com/share/p/14PRDNQXwvm/

Sounds like a sweet boat! Send pics when the time comes!

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Have you seen any updates on this yet? I was on his post the other day and saw he needs 50 orders or so… saw you on there too so if you want you can tell him you have a confirmed second order from a non-FB user

 

[Bigburb3500]

Update on transmission: I bought a bi-directional scanner, unfortunately it does not do graphing but I have fairly confidently ruled out TC issues. Lockup is fine and does not show anything unusual in the pressures. I’m starting to believe the clutches/clutch plate is worn cause the surging under heavy acceleration as the engine is overpowering the clutch packs.

**Im multiple steps below an At Home Garage Mechanic but that’s my guess at this point. It would also explain (I think) the really rough 1-2 and 2-1 shifts as the clutches are suddenly “grabbing” the gear instead of smooth engagement.

 

[Geotrash]

Have you seen any updates on this yet? I was on his post the other day and saw he needs 50 orders or so… saw you on there too so if you want you can tell him you have a confirmed second order from a non-FB user

Nothing yet, but I’ll check in there and mention it.

 

[Bigburb3500]

Update on transmission: I bought a bi-directional scanner, unfortunately it does not do graphing but I have fairly confidently ruled out TC issues. Lockup is fine and does not show anything unusual in the pressures. I’m starting to believe the clutches/clutch plate is worn cause the surging under heavy acceleration as the engine is overpowering the clutch packs.

**Im multiple steps below an At Home Garage Mechanic but that’s my guess at this point. It would also explain (I think) the really rough 1-2 and 2-1 shifts as the clutches are suddenly “grabbing” the gear instead of smooth engagement.

Ok… need some impartial and biased opinions:
I’ve been calling around and asking for general quotes to bring my truck in and get the trans rebuilt. I’m getting pretty solid $3500-6k quotes without my truck being in person, som the range makes sense.

The piece I would like opinions on are:
1) Is the 6L80/90 really that “bad” of a trans? I have never heard anything overly negative but one place that took the time and really talk “shop” with me did not have overly positive things to say about it and seemed to prefer the 4L80 and the Allison transmissions. I’ve had the 4L80 and I still blew two of those in the same truck so I’m not a giant fan of them and really do like the 6L90. Is it worth rebuilding or should I look at Powertrainswapsolutions and put a 10L90 in? **Dont tell me to just spend money because you want to see the Frankenstein monster truck LOL
2) What do yall think of the pricing? I am not summoning our resident expert, I want our contributors to weigh in on this because I think we abuse our resident expert a bit too much. He can reply IF he happens to stubble upon the thread here.

 

[Geotrash]

Ok… need some impartial and biased opinions:
I’ve been calling around and asking for general quotes to bring my truck in and get the trans rebuilt. I’m getting pretty solid $3500-6k quotes without my truck being in person, som the range makes sense.

The piece I would like opinions on are:
1) Is the 6L80/90 really that “bad” of a trans? I have never heard anything overly negative but one place that took the time and really talk “shop” with me did not have overly positive things to say about it and seemed to prefer the 4L80 and the Allison transmissions. I’ve had the 4L80 and I still blew two of those in the same truck so I’m not a giant fan of them and really do like the 6L90. Is it worth rebuilding or should I look at Powertrainswapsolutions and put a 10L90 in? **Dont tell me to just spend money because you want to see the Frankenstein monster truck LOL
2) What do yall think of the pricing? I am not summoning our resident expert, I want our contributors to weigh in on this because I think we abuse our resident expert a bit too much. He can reply IF he happens to stubble upon the thread here.

Are you sure that the surging is actually slipping? On mine, I get RPM fluctuations when towing up a long, steep hill as the TC goes in and out of lock, but the gear selection is still the same. This is true on both of my Yukons with 6L80's as well.

Personally, I think the 6L80 and 90 transmissions are excellent. Any durability problems seem to stem primarily from the programming and AFM activation causing excessive TC slippage.

On the pricing, I've been quoted $3500-$5000 from a local shop to have the 6L80 in my '07 rebuilt proactively because 1/ The truck has 250K on it and I can't tell for sure if it's ever been touched. 2/ I'd like to have the innards updated to the latest versions. 3/ I dislike breaking down and we still use that rig for a lot of roadtrips when we're not pulling a camper.

 

[Bigburb3500]

Are you sure that the surging is actually slipping? On mine, I get RPM fluctuations when towing up a long, steep hill as the TC goes in and out of lock, but the gear selection is still the same. This is true on both of my Yukons with 6L80's as well.

Personally, I think the 6L80 and 90 transmissions are excellent. Any durability problems seem to stem primarily from the programming and AFM activation causing excessive TC slippage.

On the pricing, I've been quoted $3500-$5000 from a local shop to have the 6L80 in my '07 rebuilt proactively because 1/ The truck has 250K on it and I can't tell for sure if it's ever been touched. 2/ I'd like to have the innards updated to the latest versions. 3/ I dislike breaking down and we still use that rig for a lot of roadtrips when we're not pulling a camper.

Ok so pricing seems generally in line I’m fine with that.

I am not seeing small RMP changes. I’m experiencing rough 1-2 and 2-1 shifts and under WOT there is very strange slippage at the 5-6500 RMP range where is almost feels like wheel spin then TC reducing power, then turning power on again. Except it’s not TC and I can only say it’s clutch slippage and then “grabbing” then slipping again…

 

[Geotrash]

Ok so pricing seems generally in line I’m fine with that.

I am not seeing small RMP changes. I’m experiencing rough 1-2 and 2-1 shifts and under WOT there is very strange slippage at the 5-6500 RMP range where is almost feels like wheel spin then TC reducing power, then turning power on again. Except it’s not TC and I can only say it’s clutch slippage and then “grabbing” then slipping again…

That motor is producing a lot of power in that RPM range. I wouldn’t be surprised if it was truly tire slippage with those 4:10 gears. But the rough shifts, I can’t explain. Mine is butter smooth.

 

[Bigburb3500]

That motor is producing a lot of power in that RPM range. I wouldn’t be surprised if it was truly tire slippage with those 4:10 gears. But the rough shifts, I can’t explain. Mine is butter smooth.

Not at all rolling 20MPH… maybe when the supercharger gets installed LOL.

Don’t rub it in that you got a cream puff lol. We are still operating super well. Temps don’t exceed 185° but like you said, I don’t like breakdowns… trying to prevent amid-trip interruption.

 

[Geotrash]

Not at all rolling 20MPH… maybe when the supercharger gets installed LOL.

Don’t rub it in that you got a cream puff lol. We are still operating super well. Temps don’t exceed 185° but like you said, I don’t like breakdowns… trying to prevent amid-trip interruption.

Don’t feel bad - I paid creampuff money for it too!

I’ll be interested to hear what you find out.

 

[Bigburb3500]

So I’m getting to a point where I might have my trans looked at for some of the shifting abnormalities I’ve experienced. I called a shop and owner laughed when I told him the trans I have and he said he had 15-20 6L90s in for rebuild/service. He was super leery when I told him it was tuned as he said he doesn’t recommend it at all. First time I’ve ever heard this, anyone else?

 

[Geotrash]

So I’m getting to a point where I might have my trans looked at for some of the shifting abnormalities I’ve experienced. I called a shop and owner laughed when I told him the trans I have and he said he had 15-20 6L90s in for rebuild/service. He was super leery when I told him it was tuned as he said he doesn’t recommend it at all. First time I’ve ever heard this, anyone else?

Yes, but only from tuners who don’t know the 6L80/90 as well as Justin does at blackbear. I’m at 251,000 right now on what I believe is the original 6L80 in my 2007. I’m not 100% sure, but I have no record of it being rebuilt in the Carfax, or in any of the other records that came with the car.