Interleukin6

No I don’t have a code reader but like Silverado4x4 said the check engine light disappeared by itself and everything looks ok. Can I use a code reader later when it is available to know what happened or once cleared, I can’t?

Ya~ I think so. I don’t think there are serious engine issues throwing the check engine light after the “reduced engine power” message right after oil change because my truck has been perfectly fine and oil change went through as it was supposed to be…. Has anyone had the same issue before? Thank you.

2022 LTD LT 2.7T. I just changed oil by myself today. Right after I cranked up the engine after putting new oil, my truck rumbled a little bit then threw the “reduced engine power” on the DIC. I thought it just takes a little time for new engine oil to circulate (yes, I prefilled the filter all the time). I turned off and started the engine a couple of times and drove my truck but never noticed any actual reduced engine power but the check engine light is still on the DIC whenever I started the engine. I had changed oil and filter by myself for a long time and this had never happened before. Will the check engine light be eventually cleared, or once it is on, do I need a scan tool to turn it off even though it is not an actual problem? Or I need to take mine to the dealer for possible serious issues? Thank you.

I think the gasket for the rear is reusable but not for the front.

How about this... The front differental does have enough space to work... If I just suck up old fluid then put new one without the cover off and removing metal debris on the magnet, is there no point to do this or is it better than nothing?

It seems that the prices of the original ACDelco fluids are similar to the Amsoil. The benefits I think are only one fluid treats the front & rear both (I need different fluid for the front & rear if use ACDelco) and I don’t need a fluid transfer pump… Can I use a brake cleaner to clean up the differential gears when the covers are opened? Of course I will thoroughly clean the inside of the covers, but I think I need to clean the gears as well before putting in Amsoil to prevent contamination. Is this overkill? Thanks.

Hi, about to change front and rear differential fluid. I have AAM (SU4) for the front, which takes ACDelco 10-4091 (GM 19300457) 75W-85 High Efficiency Synthetic Hypoid Gear Oil. My rear differential is GM (SU8 with G80 positraction limited slip & GU6 3.42 ratio) which takes ACDelco 10-4122 (GM 19368514) 75W-85 DEXRON Low Viscosity Gear Oil. I see many recommend swapping them with Amsoil severe gear 75W-90 100% synthetic gear lube. Can you confirm this is right fluid for the stock fluids? Looks like our trucks have 2 kinds of front & rear differentials each with their own specific fluid but can this Amsoil severe gear replace any of stock fluid? What are the benefits? Can I change fluid every 100,000 miles if I use Amsoil? I am not hauling or towing anything… thank you.

Finally, I dropped the pan today. I really appreciate all who posted good info on my previous thread, especially foundupot, newdude, & Gangly, which were a huge help! One thing I want to share… I had almost 2 qt+ fluid coming out during the temperature level procedure after putting 7.6 qts in (I know 8L90 takes 7.4 qts for pan drop but I did 0.2 qts overfill to make it easy for the level check). I was shocked and then measured how much old fluid was taken out when I dropped the pan. It was approximately 5 qts+ (yes, I spilled it some but not that much causing this difference), which should be around 7.4 qts. This is my first transmission fluid & filter change at 45K miles. I haven’t had any transmission issues. OMG!!!! I am not sure what was wrong…. I did everything exactly what all good folks told me… confused. Sorry for the long talk, just want to confirm… Does anyone know 8L90 (MQE) with L3B has a thermal bypass valve or not? Newdude previously said it doesn’t but again just want to confirm. If yes, I have to reach TFT above 194F then cool down to 95-113F to check fluid level… It takes a quite long time to cool down and I am also a little bit worried that more fluid will come out or I will need to put more fluid in…. If yes AND I just do level check 95-113F without previously reaching 194F, will it cause serious damage to the transmission? When I asked dealer, they said it would take 2 hours for transmission fluid & filter change… but I don’t think TFT can drop from >194F to 95-113F that quickly (someone said it took all day). If not, I can stop here!!! Thank you.

Fondupot, I really appreciate your input. Thank you so much.

Thank you Gangly and Black02Silverado (I will do a pan drop only, not fluid exchange.... I think it is a little bit too much for me). I was underneath my truck today to take a look.... Oh man, it seems that removing 3 bolts of the heat shield will be the hardest job during this work. There is NO space for the top 2 bolts. To make matters worse, I also saw a nut below each bolt. The nuts will not drop after removing the bolts? If yes, I have no idea how I can align the nuts when putting the bolts back there later because again literally there is no space to put my hand in. Another question is.... a truck must be leveled for the fluid level check. Mine is a stock LT in which the front is ~2 inches lower than the rear as we all know. Should I put 1 or 2 2-inch (actually 1.5-inch each) lumbar under the front tires to make it "leveled" or just putting the truck on the flat garage floor is more than enough? If I use 4-point jack stands, should I put the same height of jack stands under the frames to make it "leveled"? Please correct me if I am wrong. I think, for example, if I put them under the rear axles, my truck cannot be leveled due to rear suspension travel. Sorry for the dumb questions. Thank you again.

7.4 quarts of Mobil 1 LV ATF HP and check its level when TFT at 95-113F! Aye aye, captain! Thank you so much.

Hi, almost due for my 1st transmission fluid and filter change for 2022 1500 LTD LT 2.7 with 8L90 (MQE). I have watched a lot of youtube and read other's inputs.... I would like to confirm my questions with you guys to make sure everything is on the right track. 1. As per the owner's manual, Dextron-HP is the fluid I should put in. However, many use Mobil 1 LV ATF HP (blue label) or Amsoil instead. I prefer Mobil 1 anyway. If I use Mobil 1 or Amsoil, will it be compatible with the rest of the original fluid (I guess it is Dextron-HP of course) still remaining in the torque converter and other spaces of the transmission? Again, it is not flush but just change fluid and filter.... I just want to make sure... 2. I will do a fluid level check procedure at the end anyway but it is 7.4-7.5 quarts, right? 3. Is 35-45C (95-113F) the right transmission fluid operating temperature to check a fluid level for my 8L90? I have also read "if vehicle is equipped with a thermal bypass valve, the transmission level should be checked only after the TFT has reached or exceeded an operating temperature of 90C (194F). Once the TFT has reached or exceeded 90C (194F), then turn OFF the vehicle and allow the TFT to cool back down to 35-45C (95-113F) before checking the fluid level as required. Reaching or exceeding an operating temperature of 90C (194F) opens the bypass valve and allows the cooler to fill up with fluid, which will result in a more accurate fluid level check" How do I know mine has the thermal bypass valve or not? Just go for 194F then cool it down to 95-113F? I have noticed it is quite hard to reach 194F. I found it is only 183F when driving mine at 70 mph on the highway for 1 hour. Please share any pro tips on top of answers to my questions. Appreciate your input in advance.

I had used to pay around $90-100 after a coupon until found a large spill on the engine cover (dealer didn’t clean it) when I opened the hood later as well as failed the first state inspection at a local shop because of the corroded rear brake rotors which had never been mentioned by my dealer when they had done 3-4 oil changes with tire rotations prior (dealer replaced them after I complained a lot). Since then I have been changing oil & filter with tire rotation by myself.

Is anyone using this new Lasfit led bulbs for tail light + rear turn signal + brake light without hyperflashes? From reviewers, they are working fine but (I sent them emails twice) Lasfit keeps saying they will hyperflash with our trucks with OEM non-LED tail lights. I dont want to add resistors for led bulbs. Thanks. https://www.lasfit.com/collections/t3-series/products/7443-canbus-error-free-red-led-bulbs-t3-series

Thank you so much Gangly!!! I took more pics for a better pic but it is very narrow... it does not feel like a "leak" but some kind of rubber-like coating material..... It feels very similar to the hardened polymer material in red above. That in red might have dropped to in green when my truck was built? I don't know why it is there... Again, otherwise, no other leak signs... weird. I appreciate your expertise.

Hi, I found an old already-dried leak from the black hose (pic 1) above the oil filter when I changed the engine oil today. Looks like it dropped somewhat (pic 2) before being completely dried. I have not noticed any drops in my garage. Again, this leak must be old because it is very hard and all (in red & green color marks) dried when I touch it. What is it? Should I go to the dealer to check it? Mine is a 2022 1500 LTD LT 2.7T. Thanks. The top of the pics is towards the front of the truck and the bottom is towards the rear.

Sorry for your pain. What was your mileage you initially noticed oil consumption and oli leak? Please keep updating.

After all math, i am pretty sure my engine (2022 LTD LT 1500 2.7T currently at 38,000 miles) has consumed 0.75-1 qt oil in 3000 miles, which seems to be similar to other 2.7s... As we know, GM says 1 qt oil consumption in 2000 miles is acceptable (for not only 2.7Ts), which means it is still normal adding 3.25 qt oil between 7500 mile oil change intervals recommended by GM (ya~ we change oil sooner)? Really...? 3.25 qt is 54.16% of oil capacity (6 qt) for these engines!!!! From further research, i was shocked tons of vehicles (even from different makers) have been involved in “excessive oil consumption” issues. Is this some kind of trend in current engines? I feel there is no point bring my truck to the dealer for the oil consuming test because they will say it is still normal and also documentation will not be considered for any possible settlements in the future because again they will say it is still normal. How other 2.7 owners are dealing with this issue? Can anyone share experiences of any engine repairs under warranty or out of pocket and also tell me highest mileages on these engines without issues to know how reliable they are? Thanks.

Thank you for confirming. I was confused because “routine maintenance quick reference guide” in this forum says LT’s front sidemarker is “5WLL” same as custom, WT, & custom TB’s and they look like halogens. Thanks again.

Wow, never seen any halogen bulbs not serviceable… so if the bulb is out, it will be forever? If this is right, my truck will not pass an annual state inspection…. Can anyone confirm the front sidemarker bulbs for LT are halogen or LED? They look like halogen. Thx.

Sorry, I thought RST’s sidemarkers were halogen…

Oh, I have found an interesting service bulletin (bulletin #: 03-06-01-023E), showing, "The accepted rate of oil consumption for gasoline engines in vehicles at or above 8600 GVW is 0.946 liter (1 qt) within 379 liters (100 gallons) of fuel used" Based on this bulletin, my case seems to be normal...? which is interesting..... If I bring my truck to the dealer, they will say the same thing.... https://static.nhtsa.gov/odi/tsbs/2022/MC-10211061-0001.pdf To be honest with you, I don't mind adding 1-2 qt oil between oil changes (4-5K miles) unless my engine has problems requiring $$$-$$$$ especially when out of warranty, though some said excessive oil consumption was not covered by warranty... which is also confusing. Some owners who continuously add oil say the truck is just working perfectly, hitting nearly 100K miles. Mine too... normal oil pressure and working just fine until I found nothing was on the dipstick at 38,000 miles today, which was around 3/4 on the dipstick when I changed the oil at 35,000 miles. Can you recommend what I should do at this point? Keep changing the oil and monitoring its level until "excessive" oil consumption occurs, which will be more than 1 qt in 2000 miles in my case, or just go to the dealer? Thank you.

I’ve found there is no bulb sockets or covers to assess the front side marker bulbs for my LT. As far as I know, LT, LTZ, LT TB, & RST are still using halogen sidemarker bulbs. How can we replace them when they are out or with LED for look? Thanks.

I just found mine is also consuming oil. Nothing is on the dipstick today. I am now at 38,000 miles. I have changed oil and filter by myself since at 30,000 miles, using Mobil 1 and AcDelco PF66 filter. Most recently did at 35,000 miles. Should I now start a long battle with my dealer or just add 1 qt then enjoy mine with the powertrain warranty and then start the battle when the warranty is expired and my engine has problems? Otherwise, my truck works fine with normal oil pressure. Thanks.

I thought there might be some technical difficulties with Silverado compared to Colorado. Thank you.