Transmission woes?

[5strmtrp]

I’m at 155xxx miles on my SSV. Recently had some sluggishness that I thought was throttle related. Replaced TB & Gas pedal with little to no difference.

I check my fluids on the truck weekly to make sure all are up to capacity.

So here is my ?’s to you all…

The trans fluid is getting dark in color and smells burnt. So… I think it’s time for a rebuild. Last time I changed the fluid was around 125,*** give or take.

With the rebuild what is the general suggestion. Trans and torque converter, change out my sweating lines, replace the cooler with a larger one.

Would you also change out the transfer case as well?

 

[Joseph Garcia]

@NickTransmissions

 

[Marky Dissod]

... ATF is getting dark in color and smells burnt. So … think it’s time for a rebuild. Last time I changed the fluid was around 125,*** give or take.

Prove it. Get your used ATF analyzed. All we can do is jawjack - no, fingerjack about past longevity statistics.
If for whatever reason you still have your used ATF, analysis of it will give you a much more definitive answer, compared to our speculations.

If your torque converter is truly GM OE, and it has not yet failed you, IT is the chief cause of 6L80E rebuilds between 80,000 and 160,000 miles.
Specifically, the torque converter CLUTCH. It wears and wears, but then it FAILS for some reason (more on that in a bit).
When it fails, its detritus takes out the rest of the 6L80E.
In other words, you almost certainly need a new torque converter, whether or not you need a rebuilt 6L80E.
Find out how much a GM OE converter costs,
then see how much of an upgrade you can get from the aftermarket for a competitive price
(so your spouse can't call it wasting money) after considering how hard your SSV works and/or plays.

GM OE 6L80E and torque converter clutch programming are the other major reason for most rebuilds.
OE programming sacrifices durability / longevity for minimal NVH and CAFE MpG scores that most people can never achieve.
For example, even 6L90E OE programming is as durable / long-lived ... behind a 6.6L DuraMax.
Simply improving on the original TCC programming would makes things last longer, even if you drive GENTLY.
Long story short: have your tcm tuned (your ecm too, but that's a different story), your 6L80 will last longer

Hopefully @NickTransmissions will tell you better.

 

[Marky Dissod]

Forgot to say two things:
since it's an SSV, it may already have 3.42. If for whatever reason you find its nature sluggish
(generally, not as a symptom), and/or you want it to be able to work / play harder without breaking a sweat,
3.73.

If your SSV does not AND will not work or play hard, you can just add a fan to the external ATF cooler it already has.
If you want your SSV to work and or play hard (or harder), upgrade the external ATF cooler,
and very seriously consider 3.73 and a tcm tune.

 

[5strmtrp]

Thank you for the information.

I haven’t dropped the pan yet as the filter & gasket are on order. Weird can’t just go to NAPA n pick one up.

Where is the best place to send the fluid to?

I’m willing to do either a torque converter or a trans on this truck. It’s paid for it’s our go to in crummy weather. It’s frigging cheaper than a newer car payment!

Programming I have a local ish tuner that I’ve taken my Caprice to, however is there someone out there that I can send the TCM & BCM etc to?

It is the original transmission in the truck to the best of my knowledge. I purchased it in ‘18 with under 100xxx on it. Performed at least 2 fluid n filter changes since I’ve owned it.

I’m not aggressive with it but will use the “force” to get it up to highway speeds. I’ve towed many things behind it the heaviest was the U-Haul auto transport with a ‘77 Seville on it for a few hundred miles in the summers heat.

 

[5strmtrp]

Forgot to say two things:
since it's an SSV, it may already have 3.42. If for whatever reason you find its nature sluggish
(generally, not as a symptom), and/or you want it to be able to work / play harder without breaking a sweat,
3.73.

If your SSV does not AND will not work or play hard, you can just add a fan to the external ATF cooler it already has.
If you want your SSV to work and or play hard (or harder), upgrade the external ATF cooler,
and very seriously consider 3.73 and a tcm tune.

It does have the 3.42. It is the plan to get a larger cooler on this thing. I generally see temps steady 190-200 in ambient temps above 60 degrees. This is According to the DIC. We all know that it can be inaccurate

 

[Doubeleive]

Thank you for the information.

I haven’t dropped the pan yet as the filter & gasket are on order. Weird can’t just go to NAPA n pick one up.

Where is the best place to send the fluid to?

I’m willing to do either a torque converter or a trans on this truck. It’s paid for it’s our go to in crummy weather. It’s frigging cheaper than a newer car payment!

Programming I have a local ish tuner that I’ve taken my Caprice to, however is there someone out there that I can send the TCM & BCM etc to?

It is the original transmission in the truck to the best of my knowledge. I purchased it in ‘18 with under 100xxx on it. Performed at least 2 fluid n filter changes since I’ve owned it.

I’m not aggressive with it but will use the “force” to get it up to highway speeds. I’ve towed many things behind it the heaviest was the U-Haul auto transport with a ‘77 Seville on it for a few hundred miles in the summers heat.

blackstone labs, you can call them or go online and request a sample kit, cost's like $30-40 for various sample types requested for most stuff, turn around has been about 3 weeks, you can pay for the analysis and then when you get the kit you just write your order number on it and mail it in.

 

[5strmtrp]

Looking them up!

Thankfully I’m not dealing with hard shifts or to me slippage. Hopefully it’s caught early enough. I get the programming done add a better external cooler, converter, and look into better gearing. The gearing would require both the front and rear to be done.

 

[Marky Dissod]

I’m willing to do either a torque converter or a trans on this truck.

If you do rebuild / replace the transmission, do the torque converter too.
Most transmission warranties specify replacing the torque converter as a qualifying condition.
New 6L80 + old torque converter = very short-lived 6L80 with no warranty.

Programming I have a local ish tuner that I’ve taken my Caprice to, however is there someone out there that I can send the TCM & ECM to?

You didn't ask your LT1 Caprice tuner? Or your LT1 Caprice tuner didn't have a good answer?
BlackBear Performance comes highly recommended here.
PCM Performance (20 years experience) comes highly recommended by me (and 20 years of others).
There are other reputable tuners out there.
You'll likely get best results from a tuner who uses your realtime driving data to inform the finer points of your ecm & tcm tune.

It is the original transmission to the best of my knowledge. Purchased it in ‘18 with under 100xxx on it. Performed at least 2 ATF n filter changes since I’ve owned it.

I’m not aggressive with it but will use the “force” to get it up to highway speeds.
I’ve towed many things behind it the heaviest was the U-Haul auto transport with a ‘77 Seville on it for a few hundred miles in the summers heat.
...
I get the programming done add a better external cooler, converter, and look into better gearing. The gearing would require both the front and rear to be done.

I hesitate to say, it sounds to me like you may not want / need 3.73?
If that turns out to be the case, your external ATF cooler may only need a helping fan on it.
A thorough ecm & tcm tuning, among many other things, does address radiator fan cooling temp thresholds as well.

Speaking of ATF thermal management, you may want to ask about 'flipping your pill', or something ...

 

[NickTransmissions]

I’m at 155xxx miles on my SSV. Recently had some sluggishness that I thought was throttle related. Replaced TB & Gas pedal with little to no difference.

I check my fluids on the truck weekly to make sure all are up to capacity.

So here is my ?’s to you all…

The trans fluid is getting dark in color and smells burnt. So… I think it’s time for a rebuild. Last time I changed the fluid was around 125,*** give or take.

With the rebuild what is the general suggestion. Trans and torque converter, change out my sweating lines, replace the cooler with a larger one.

Would you also change out the transfer case as well?

Everything you ever wanted to know about the 6L80 trans can be found here:

GM 6L80 Transmission Information Thread

Hi All, Since so many of us own at least one Tahoe or Yukon equipped with a 6L80, I figured I'd start an all-encompassing transmission thread with videos, links and other information as it relates to the 6L80/90 transmissions. I'll get it going with a tear down and inspection video and go from...

www.tahoeyukonforum.com

What are 'sweating' lines' in this context? I get those in the summer when it's hot but never seen them on a vehicle...