Blackstone Labs Transmission Report

[Doubeleive]

Same here…I can feel mine ready for a catastrophic fail anytime now. I’m guessing that was the main cause of all the “extra material” when I drained the pan. Plus the lack of fluid change by the previous owner didn’t help any.
I’m already planning to replace the bell housing like you mentioned…was your oil pump still in good shape, or did the TC cause any damage? I’ve seen them seize right up in other vehicles, but never any of the 4.3, 5.3, 6.2’s.

i'm thinking the pump was ok it wasn't on the invoice but from what I understand when the TC goes in these it takes out the pump with it. the shop never mentioned replacing it either.

 

[Geotrash]

*as such, has anyone done a swap from the 6L80 TC to the 6L90? Has it show any better performance or extended life after reaching their typical “high mileage” range.

I had a CVC BU60FHD installed in mine earlier this year. It's a factory unit remanufactured with a stronger lockup clutch and billet front housing. Ran me about $1300 IIRC, installed with a new rear main seal. I did it proactively because I do a lot of towing. Performance is the same as stock as far as I can tell.

 

[89Suburban]

I figured out another way to help you fellas spend money on your trucks!

Research revealed that the average life of a GMT-900 6L80 transmission was about 160K miles. So with that milestone coming up I wanted to see if mine was on the same path or not for overhaul or replacement. The least intrusive way was to have Blackstone-labs analyze a sample of fluid for me; so that's what my daughter and I did.

Sample was pulled from a cold vehicle by removing a line from the radiator with a Jiffy-Tite tool and caught the fluid with a quick run of the engine. Half the fluid made it into the container and the rest made a mess. We then guesstimated how much was lost and then topped off and shut the hood. The sample was frothy and purplish in color.

A little background, all of the fluid was changed by my local dealership in August of 2017 at 117,432 miles. Based on the color and internal oil life monitor, I believe this was the first time that the fluid had been changed. At the end of February of this year the mileage was approaching my artificial, 36K mile limit to change all the fluids again. I was wanting to get the truck on an even 50K schedule at 150K but missed it by a little bit. The internal OLM shows in the 70s percentile range right now.

Anyhow, after receipt of this report the fluid will be exchanged again and probably kept on a similar schedule of 36K or so miles.

As always, comments and opinions and advice appreciated.

Who's next?

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That's a great report friend, happy for you!

 

[swathdiver]

I had a CVC BU60FHD installed in mine earlier this year. It's a factory unit remanufactured with a stronger lockup clutch and billet front housing. Ran me about $1300 IIRC, installed with a new rear main seal. I did it proactively because I do a lot of towing. Performance is the same as stock as far as I can tell.

View attachment 353980

It's my understanding that Sonnax makes these parts and offers them to trans and converter shops and they put them into the converters like this one. I have not seen a Sonnax converter but have heard of the parts being used by different converter builders and maybe this one too. What say you? What is the going rate on these converters these days?

 

[Geotrash]

It's my understanding that Sonnax makes these parts and offers them to trans and converter shops and they put them into the converters like this one. I have not seen a Sonnax converter but have heard of the parts being used by different converter builders and maybe this one too. What say you? What is the going rate on these converters these days?

I'd have to dig into my file box for the receipt, but I think the converter itself was around $450.

And yes, I think you're right that the overhaulers will usually use parts from Sonnax and others depending on the application.