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I was ordering a test kit for my engine oil from Blackstone labs and I saw "Transmission" was a choice for a test kit as well. I will be changing my transmission fluid at the same time so I thought I would get a kit and test that too. This will be the 2nd time I've changed the fluid which has 45k miles on it. Didn't know if anyone else had done it? Just wanted to see if I might be throwing my money away 馃檭
 

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I had my transmission flushed and refilled at 7,700 mi with what I believe is a better fluid with which I have had significant experience. The flush also took care of most debris, if any, from mfg.
I just had my 2nd and last 'free' oil change at 13,300 mi, and sent samples of oil (2nd) and fluid (1st) to Blackstone last week.
My objectives are to get a low mileage baseline for the fluid and sample it every 3-4 engine oil changes in the future to see how it is holding up. As you are probably aware, the Manual specifies 45,000 mi fluid changes for severe duty (I don't tow or haul heavy loads) and there is NO recommendation otherwise.
For the engine oil, I want to monitor how the motor is setting in, and observe the performance of the Dexos2 5w30 insofar as soot, TBN and other parameters. I will do my own next oil change using an ACEA C3 2016 5W40 (also meets, but not certified Dexos2) to use for comparison both for oil analysis and observable differences in the Provent 200 oil drain, if any.
The tech I have used and specified in the past at Blackstone has been very helpful and informative.

Yes, the analyses now cost $30 +$10 ea for soot and TBN, but changing oil only twice a year is not a concern to me considering this truck is a planned long-term hold. Maybe later I will back off somewhat on the oil, but for now I want to learn from what the analysis has to offer.
Why not try a fluid analysis to see how it is holding up, esp. if you are severe service qualified?
 
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Fluid analysis reports are a good investment come resale time if you sell privately as they really impress potential buyers.

I like buying private party one owner used vehicles as I buy the owner as much as the vehicle. If the owner is a dumbass, I pass, even if the vehicle looks halfway decent. On the other hand, if the owner impresses me, I am interested, as people who have their stuff together tend to take care of their vehicles. The prior owner's situation is a big mystery when buying used from a dealer.
 

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Discussion Starter #4
I had my transmission flushed and refilled at 7,700 mi with what I believe is a better fluid with which I have had significant experience. The flush also took care of most debris, if any, from mfg.
I just had my 2nd and last 'free' oil change at 13,300 mi, and sent samples of oil (2nd) and fluid (1st) to Blackstone last week.
My objectives are to get a low mileage baseline for the fluid and sample it every 3-4 engine oil changes in the future to see how it is holding up. As you are probably aware, the Manual specifies 45,000 mi fluid changes for severe duty (I don't tow or haul heavy loads) and there is NO recommendation otherwise.
For the engine oil, I want to monitor how the motor is setting in, and observe the performance of the Dexos2 5w30 insofar as soot, TBN and other parameters. I will do my own next oil change using an ACEA C3 2016 5W40 (also meets, but not certified Dexos2) to use for comparison both for oil analysis and observable differences in the Provent 200 oil drain, if any.
The tech I have used and specified in the past at Blackstone has been very helpful and informative.

Yes, the analyses now cost $30 +$10 ea for soot and TBN, but changing oil only twice a year is not a concern to me considering this truck is a planned long-term hold. Maybe later I will back off somewhat on the oil, but for now I want to learn from what the analysis has to offer.
Why not try a fluid analysis to see how it is holding up, esp. if you are severe service qualified?
I don't tow hardly at all. However, these transmissions or more-so the torque converter I believe, have an issue with bad fluid. Or, maybe it's the original fluid the trucks come with. Many complain of shuttering transmissions. Generally, that goes away when one changes the fluid, either doing just a drain and pan drop w/ filter like myself, or a whole system flush.

I am not experiencing any shuttering, but as I only did a pan drop at 45k miles, I only got 6-7 qts. of fluid out. So, while the fluid (AMSOIL) I put in last time is now used, I would like to try and get more of that original factory fluid out so I'm changing it again at 90k miles. I don't trust flush machines, too many bad stories I have heard. All of my vehicles that I've done pan drops with have gotten along just fine with them. Changing the fluid I see more of as regular maintenance. I know the manual says "only change for severe service." However, it's something that can be replaced easily enough.
 

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Whatever works best for you!

I believe the shuddering issues are part of the 8 spd transmission story.
Also using a quality ASE shop to do a flush has been my preference. My 'analysis plan' will suffice for my needs.

As a full-time RVer, I don't see myself dropping any pan, anywhere. I change the oil in my Coach and genset myself on an annual basis, and will also do the Colorado now that my 'freebies' are done. I have an 18 qt drain container and all sumps are fitted with Fumoto valves for no mess drains
 

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Discussion Starter #6
Whatever works best for you!

I believe the shuddering issues are part of the 8 spd transmission story.
Also using a quality ASE shop to do a flush has been my preference. My 'analysis plan' will suffice for my needs.

As a full-time RVer, I don't see myself dropping any pan, anywhere. I change the oil in my Coach and genset myself on an annual basis, and will also do the Colorado now that my 'freebies' are done. I have an 18 qt drain container and all sumps are fitted with Fumoto valves for no mess drains
You are correct about the 8 speeds shuddering. But, the 6 speed also has it in some instances. Primarily because the torque converter is failing typically. There are accounts of this on here (search for them) and on the Facebook groups. The 6 speed is more trouble free than the 8 speed but not without occasional problem children.
 

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I spoke to a COFans board member on the phone yesterday, he has a '16 diesel with 75K on it, has had steadily worsening shudder issues for 2 years. He is getting his TC replaced, not covered under warranty of course. He had a GDE engine and trans tunes on it since 45K miles, it had a problem with shudder before he tuned it though, he was hoping the trans tune would fix it. Instead by delaying and tuning it, he cause himself an expensive problem. The takeaway from that is if one has shuddering and it is within warranty, dog GM, don't let it slide. Also, like any mechanical problem, a shuddering trans does not get better with time if ignored. Even if no warranty applies, address the problem sooner than later.

One thing he said that was interesting - he drove his truck very gently, seeking good fuel economy. I do think it is better for the trans to accelerate briskly and get up to speed. The trans will respond to that and lock up sooner and firmer. Slipping the transmission's clutches a lot is bad. One does not need to hot rod it, but enjoy the diesel torque and let her eat when accelerating :cool:
 
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Can this 'shuddering' issue be evidenced at idle rpms? I am pretty sensitive to vibrations/sounds on the truck and once in a while, usually after a warm restart, I feel a slight vibration at steady idle rpms (750) when leaving a parking lot at a stop sign before pulling out into the street. That vibration goes away immediately and doesn't reoccur again for days/weeks even under very similar conditions.
Up till now I have treated this as just the ECM trying to figure out 'what to do' as it 'wasn't expecting me back so soon'!
 

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Chevy "recently" changed out their trans fluid, going with a full synthetic. I changed mine just shy of the "severe service" interval, and am running that. I'll order this kit for my next change, and post readings for the greater good. But it's gonna be awhile, so anyone with knowledge on whether I made a good decision, or should have gone with some after market elixir, please let me know...
 

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Chevy "recently" changed out their trans fluid, going with a full synthetic. I changed mine just shy of the "severe service" interval, and am running that. I'll order this kit for my next change, and post readings for the greater good. But it's gonna be awhile, so anyone with knowledge on whether I made a good decision, or should have gone with some after market elixir, please let me know...
I installed a deep PML trans pan and elected to go with the Mobil 1 LV HP "blue label" synthetic fluid used for the 8 speeds. All I can say is the 6 speed loves this fluid. It shifts super smooth and a bit quicker now. Looked at the specs of this fluid, it has a higher viscosity index than Dex 6 and is thinner when cold than Dex 6 but does not thin out as much as Dex 6 when hot. The viscosity difference is not that great. Anyway, while technically not Dexron 6, the LV HP fluid is working great in my 6 speed.
 

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I had my transmission flushed and refilled at 7,700 mi with what I believe is a better fluid with which I have had significant experience. The flush also took care of most debris, if any, from mfg.
I just had my 2nd and last 'free' oil change at 13,300 mi, and sent samples of oil (2nd) and fluid (1st) to Blackstone last week.
My objectives are to get a low mileage baseline for the fluid and sample it every 3-4 engine oil changes in the future to see how it is holding up. As you are probably aware, the Manual specifies 45,000 mi fluid changes for severe duty (I don't tow or haul heavy loads) and there is NO recommendation otherwise.
For the engine oil, I want to monitor how the motor is setting in, and observe the performance of the Dexos2 5w30 insofar as soot, TBN and other parameters. I will do my own next oil change using an ACEA C3 2016 5W40 (also meets, but not certified Dexos2) to use for comparison both for oil analysis and observable differences in the Provent 200 oil drain, if any.
The tech I have used and specified in the past at Blackstone has been very helpful and informative.

Yes, the analyses now cost $30 +$10 ea for soot and TBN, but changing oil only twice a year is not a concern to me considering this truck is a planned long-term hold. Maybe later I will back off somewhat on the oil, but for now I want to learn from what the analysis has to offer.
Why not try a fluid analysis to see how it is holding up, esp. if you are severe service qualified?
i have used oil analysis for ovr 30 years now.i used to use DA SPEED SPORT OIL AND THEY GAVE YOU A FREE ANALYSIS WITH EACH CASE. i dont know if they even make the oil anymore but i thought i would share with everyone how important it is: i sent a q966 ferrari v12 engine to detroit to a man( terry myr) who with a team of other GM engineers rebuilt italian exotic engines in their spare time. i had him put everything new in he brought new borgo liners and pistons back from italy ,cam chaine,etc,etc . the motor was sent back and ran perfectly. my analysis of the oil kept coming up over the limits moisture content but it was not milky as water in the oil looks usually like milk. i instantly knew there was something wrong. i live in florida so i insisted he ship the car to detroit and back . i felt like it was not my mistake thus swallowing the labor of taking the motor out as well as reinstalling it. in 1979 i spent $14,000 on the motor( equal to approx $50,000 today) sure enough they found the problem in installing one of the new liners there was not a 100% seal at the bottom of the liner( was not driven in the block all the way.if i remember right, it was about 1 mm from proper sealing. they made it right and never had another problem with the engine. i think terry is still in buisness and would recommend the company as he fixed it with no fuss. about 6 months later i restored a classic mercedes 200 diesel for my brother to commute to college with. i had the motor built by the best local machine ship in the area. once again found high levels of moisture in the oil analysis. had them tear it down and they found a leaking new head gasket.they redid the motor and never had another problem. IF i did not have the analysis i would have had 2 very expensive engine failures once the engines were past warrenty repair, $20,000 worth of engine overhauls( in late 70's money WAY more today ) buys ALOT OF $30 analysis's.i do the same thing on my body called functional medicine i have the boston heart institute check an in depth analysis of my blood twice a year. its amazing how much they can tell you much like the oil analysis!!
 
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