Chevrolet Suburban 3500 Questions

[Geotrash]

Add another Suburban 3500 owner to the forum. Will be nice to be in company with some other enthusiasts. Will start thread with details of my build.

Welcome, Kevin! We’ve chatted on FB a few times.

 

[Bigburb3500]

Add another Suburban 3500 owner to the forum. Will be nice to be in company with some other enthusiasts. Will start thread with details of my build.

Welcome aboard! Can’t wait to see the build thread and already love the push bar!

 

[1TONSUB]

Thanks guys. Nice to have a couple other resources for these. I am thinking my next mod will be the black bear tune mostly for transmission preservation. I believe I read you were happy with results?

I do not like that I can feel the torque converter lock and un locking all the time and can see how that will lead to future wear. I know there is some power to be had running higher octane fuel but I am not interested in that. I am satisfied at this point with 87.

 

[Bigburb3500]

Thanks guys. Nice to have a couple other resources for these. I am thinking my next mod will be the black bear tune mostly for transmission preservation. I believe I read you were happy with results?

I do not like that I can feel the torque converter lock and un locking all the time and can see how that will lead to future wear. I know there is some power to be had running higher octane fuel but I am not interested in that. I am satisfied at this point with 87.

Yes, both Geo and I have the BBP tune and we have both engine and trans tunes. It is really a great product and wakes the truck up a lot! The shifts are much more purposeful and drives more confidently.
I run 87 with no issue.

I will notate that I have not seen any mpg improvement. It is nearly identical from before the tune.

 

[Bigburb3500]

Also, speaking of transmissions, I will be doing a transmission fluid and filter change this week. Starting tonight and already have the truck up on blocks to more easily get under the truck.

 

[Geotrash]

Thanks guys. Nice to have a couple other resources for these. I am thinking my next mod will be the black bear tune mostly for transmission preservation. I believe I read you were happy with results?

I do not like that I can feel the torque converter lock and un locking all the time and can see how that will lead to future wear. I know there is some power to be had running higher octane fuel but I am not interested in that. I am satisfied at this point with 87.

Yes, I have a Blackbear tune on both of my Yukon XL Denali's and on the Suburban 3500. It makes the shifts quicker (less clutch slipping), and tightens up the converter locking. You can also ask for their recommendations on changing which gears the TC locks up in for towing duty. When I submitted my order I told them how I use the truck (mainly for towing), and that I still wanted to be able to use 87 octane when needed. Justin sent back 2 tunes - one for 87 and one for 91. He suggested that 89 octane would provide an optimal balance between power and fuel efficiency on the 87 tune, so that's the one I installed.

Since the Denali's need premium - especially when towing - regardless of the tune, I'll likely save money on fuel towing the same camper with the 3500. Mileage is about the same though I haven't run any hand calculations yet. We have a 3,000 mile trip coming up at the end of June so I'll know more after that trip.

 

[89Suburban]

I do not like that I can feel the torque converter lock and un locking all the time and can see how that will lead to future wear.

I hate this as well. Drives me nuts how the factory tune wants this transmission to lug like that. I am itching to get a tune done.

 

[1TONSUB]

Also, speaking of transmissions, I will be doing a transmission fluid and filter change this week. Starting tonight and already have the truck up on blocks to more easily get under the truck.

Would love to hear how that goes. Did you install a dip stick? Adapter to fill from pan or dip stick? Fluid choice? Pan drop clears exhaust? Thanks. I would like do this as well.

 

[1TONSUB]

Yes, I have a Blackbear tune on both of my Yukon XL Denali's and on the Suburban 3500. It makes the shifts quicker (less clutch slipping), and tightens up the converter locking. You can also ask for their recommendations on changing which gears the TC locks up in for towing duty. When I submitted my order I told them how I use the truck (mainly for towing), and that I still wanted to be able to use 87 octane when needed. Justin sent back 2 tunes - one for 87 and one for 91. He suggested that 89 octane would provide an optimal balance between power and fuel efficiency on the 87 tune, so that's the one I installed.

Since the Denali's need premium - especially when towing - regardless of the tune, I'll likely save money on fuel towing the same camper with the 3500. Mileage is about the same though I haven't run any hand calculations yet. We have a 3,000 mile trip coming up at the end of June so I'll know more after that trip.

Thanks for info. Sorry to confirm you run 89 fuel on the 87 tune? Do you keep the programmer installed or just flash the tune then remove the autocal. Curious if you enjoy the other data available from the autocal when driving...

 

[TripleFJeff]

Add another Suburban 3500 owner to the forum. Will be nice to be in company with some other enthusiasts. Will start thread with details of my build.

Curious where yours came from. I’ve been watching what is available around the country and didn’t see that one, unless the wheels and other stuff went on after you got it.

 

[1TONSUB]

Curious where yours came from. I’ve been watching what is available around the country and didn’t see that one, unless the wheels and other stuff went on after you got it.

Bought from dealer in Lock Haven Pennsylvania in March 2021. Saw it listed and drove out to see within days. Looked for couple years before I found one. It was stock I added stuff.

 

[TripleFJeff]

Bought from dealer in Lock Haven Pennsylvania in March 2021. Saw it listed and drove out to see within days. Looked for couple years before I found one. It was stock I added stuff.

Ah, thought you had just gotten it. Saw it’s a LT. Nice find.

 

[Geotrash]

Thanks for info. Sorry to confirm you run 89 fuel on the 87 tune?

Yes, that's right.

Do you keep the programmer installed or just flash the tune then remove the autocal. Curious if you enjoy the other data available from the autocal when driving...

It's just a flash process and then you're done with the tool. It only has a simple LCD screen with menus, but no live data display. I have HP Tuners with a laptop for logging live data while I drive, if I need to for some reason.

 

[Bigburb3500]

Thanks for info. Sorry to confirm you run 89 fuel on the 87 tune? Do you keep the programmer installed or just flash the tune then remove the autocal. Curious if you enjoy the other data available from the autocal when driving...

I run 87 octane and pretty sure they set up the tune for the low octane. This truck is a rocket compared to my previous daily driver lol.

I just flashed and removed the AutoCal. No need to review the data as this is 100% a daily driver right now and does not get used for heavy towing at this point.

For the trans oil:
I have the dipstick and all pieces for it but I can’t find the nut and washers I bought so might have to do a trip to HD real quick. I have a small hand pump which I will suck out as much fluid as I can then drop the pan. I think there should be plenty of space around the exhaust.
I bought fluid from Tractor Supply. It was on sale for $15/gal. It’s the right version of Dextron so kinda hard to not buy at that price when WalMart was $30/gal.
Filter was just from Amazon as they are all the same. I plan to reuse the gasket based on other threads and recommendations.

 

[89Suburban]

Good stuff guys.

 

[Bigburb3500]

Transmission oil update
Time: Approx 3hrs
Difficulty: Low
Most difficult Step: Removing the filter collar gasket. Took almost an hr…

Plenty of space to remove pan with doing anything with the exhaust. My pan was SPOTLESS. The magnet had a little debris on it but the actual pan was clean. The color was more than acceptable but it did smell a little. The new stuff is much more red so it was needed at 79,950 miles.

I got the fluid level set but have not taken the truck for a drive yet. I am going to add the dip stick tomorrow.

Let me know if you have questions, sorry I didn’t take pictures… I’m obviously not a professional blogger or YouTuber lol.

 

[Geotrash]

Transmission oil update
Time: Approx 3hrs
Difficulty: Low
Most difficult Step: Removing the filter collar gasket. Took almost an hr…

Plenty of space to remove pan with doing anything with the exhaust. My pan was SPOTLESS. The magnet had a little debris on it but the actual pan was clean. The color was more than acceptable but it did smell a little. The new stuff is much more red so it was needed at 79,950 miles.

I got the fluid level set but have not taken the truck for a drive yet. I am going to add the dip stick tomorrow.

Let me know if you have questions, sorry I didn’t take pictures… I’m obviously not a professional blogger or YouTuber lol.

Awesome! I'll be more interested in your pictures of the dipstick install!

 

[Bigburb3500]

Awesome! I'll be more interested in your pictures of the dipstick install!

I will do my best to grab some!

Funny, doing the trans oil and the dip stick at the same time makes it pretty easy. There is no wrestling of the rubber stopper as you can push on it from inside the transmission. When it’s out you can pre-load your fill mechanism, put on the pan, then get it filled right, then finally install the dip stick. That is where I’m at today. Let the truck cool overnight so I don’t burn myself on the exhaust.

 

[1TONSUB]

Nice work. Thanks for inspiration. I am going to do this also. I had dealer change fluid before 50k now near 75k and going to do pan drop + filter like you at some point. Care to share dipstick used? I found this one Lokar TD-36L80FM Transmission Dipstick https://www.amazon.com/gp/product/B003JBM64A/ref=ox_sc_saved_title_8?smid=A1FJ1WMPKJVUMQ&psc=1
For future reference how many quarts was your drain and fill pan drop method?

 

[Bigburb3500]

Nice work. Thanks for inspiration. I am going to do this also. I had dealer change fluid before 50k now near 75k and going to do pan drop + filter like you at some point. Care to share dipstick used? I found this one Lokar TD-36L80FM Transmission Dipstick https://www.amazon.com/gp/product/B003JBM64A/ref=ox_sc_saved_title_8?smid=A1FJ1WMPKJVUMQ&psc=1
For future reference how many quarts was your drain and fill pan drop method?

I used this site to get part numbers:

Installing a transmission dipstick for the 6L90 (L8T gas trucks) using factory fit GM parts.

A direct fit transmission dipstick is available for 2020-2023 HDs using part numbers from a 2019 model. You will need the following: Dipstick tube: 24265546 Dipstick (indicator): 24271875 Seal/grommet for dipstick tube: 15796802 (1) Flange Nut or lock/flat washer & nut: M8-1.25 Start by crawl...

www.gm-trucks.com

Then just found the cheapest/easiest ones to get my hands on. I think I ended up ordering from RockAuto (discounts available on the forum).
The unobtainium is the gasket/grommet for the dip stick. Took me almost 2mo to get it because you cannot order them individually but long in short, I have a few now due to my order taking so long. PM me if you struggle with getting one.

Total with drop and fill is about 5ish quarts. I will be doing the dipstick then will verify level of oil again.