2010 Sierra 4L60E Questions

[kevhawk]

New member here, long time lurker with another 4l60e question thread haha

I've got a 2010 Sierra 1500 SL 4.8 no-AFM with a 4L60E and a manual transfer case that just hit 70k KM, I bought this truck about 2 years ago at the 60K mark and did it's first transmission service. The fluid looked decent maybe a bit dark, magnets had caught some material but that was it. Nothing looked out of place and the filter seemed fine. The transfer case on the other hand the fluid was pretty rough lol

Reinstalled a new WIX filter and a extra magnet in a new dorman pan so I'd have a drain for next time. Filled it with some Pennzoil Platinum LV/Dextron 4 in both the transmission and transfer case as that's what the local Napa had.

One of the things that's always bothered me though is part-throttles 1-2 shifts at residential speeds is very much a jarring sliiide and bump. If you are a bit more aggressive on the throttle it shifts great every time. I've thought about playing around with the tuning with HPTuners or EFILive as I have access to that or a 1-2 pinless accumulator upgrade but could never really nail down some good guidance.

Some upgrades I've already done was a Tru-Cool 40K with a Derale thermostat. The transmission lines were leaking as they all do so I took at opportunity to install the thermostat on the hardlines bypassing the rad cooler. Our winters are very rough at around -40.F/C so I wanted to make sure the trans had a chance at warming up.

With that long winded explanation over I guess I'm looking for some thoughts. I've read a lot of conflicting information across the internet about this I'm just looking for maximum reliability out of this thing. Is that 1-2 shift slide bump shift something I should be concerned about for long term reliability? Is there some more mods I can do to the truck to give this thing a better longer life?

The other thing I've been trying to chase down for a while is this thing has a horrible clunk on the throttle I've inspected u-joints and everything several times and I can't figure out where it's coming from. The only play I've found is the rear diff itself perhaps I need to pull the cover on that as well.. Scared of what I may find...

Thanks for reading!

 

[Urshurak776]

I will tell you that my GMC Sierra with same transmission was a fantastic truck. Ditched it after 328K because the transmission failed for the third time. Every 110K-120K...kabamo!

Didn't matter what I did. Maintenance like you just did, babied it, didn't matter. I never even used it as a truck much to be honest. Maybe a couple trips with some lumber from big box store, moved a couch, etc. Never towed with it.

4L60E, for me, wasn't great. I hope it works out better for you.

 

[350Rocket]

I will tell you that my GMC Sierra with same transmission was a fantastic truck. Ditched it after 328K because the transmission failed for the third time. Every 110K-120K...kabamo!

Didn't matter what I did. Maintenance like you just did, babied it, didn't matter. I never even used it as a truck much to be honest. Maybe a couple trips with some lumber from big box store, moved a couch, etc. Never towed with it.

4L60E, for me, wasn't great. I hope it works out better for you.

Was that the same core just rebuilt each time? Same rebuilder? Just curious about the details because we've had several at work and none have failed. Also experienced a few at the shop I used to work at with a lot of miles. The one I personally know that failed at like 80k miles was my father in law with his 04 express van 5.3L 4L60E. But after riding with him my conclusion is it was probably his driving style. He thinks he's an expert on everything but I don't think he even knows not to tow in overdrive and he tows basically every day and has the van loaded with a massive amount of tools and supplies.

 

[Urshurak776]

Was that the same core just rebuilt each time? Same rebuilder? Just curious about the details because we've had several at work and none have failed. Also experienced a few at the shop I used to work at with a lot of miles. The one I personally know that failed at like 80k miles was my father in law with his 04 express van 5.3L 4L60E. But after riding with him my conclusion is it was probably his driving style. He thinks he's an expert on everything but I don't think he even knows not to tow in overdrive and he tows basically every day and has the van loaded with a massive amount of tools and supplies.

First time it was my Dads truck. He lives in Central Texas. I got the truck from him when it went 100K later and had it done in Georgia where I lived at the time. Then, 100K later, had it done in Charlotte, NC. Never used the truck for towing. The second time it was done it had an "upgraded" heavy duty sunshell upgrade. Didn't matter.....supposedly latest and greatest enhancements when I had it done in Charlotte.

So, not sure, but every 100-120K.....#fail. Never had a transmission fail on me before this truck, or ever since.

 

[350Rocket]

First time it was my Dads truck. He lives in Central Texas. I got the truck from him when it went 100K later and had it done in Georgia where I lived at the time. Then, 100K later, had it done in Charlotte, NC. Never used the truck for towing. The second time it was done it had an "upgraded" heavy duty sunshell upgrade. Didn't matter.....supposedly latest and greatest enhancements when I had it done in Charlotte.

So, not sure, but every 100-120K.....#fail. Never had a transmission fail on me before this truck, or ever since.

It just makes me wonder if some of them have a factory defect that's getting missed when rebuilt, allowing them to fail repeatedly. In fact I would bet $ on it since some of them last 200k-300k from the factory despite abuse. They can definitely be hit or miss but my experience has been mostly positive.

 

[kevhawk]

I will tell you that my GMC Sierra with same transmission was a fantastic truck. Ditched it after 328K because the transmission failed for the third time. Every 110K-120K...kabamo!

Didn't matter what I did. Maintenance like you just did, babied it, didn't matter. I never even used it as a truck much to be honest. Maybe a couple trips with some lumber from big box store, moved a couch, etc. Never towed with it.

4L60E, for me, wasn't great. I hope it works out better for you.

Yeah I'm hoping for a bit more longevity especially with some guidance for some mods to help it live longer. But my expectations are realistic if it throws it at 100k so be it I can pull it and I'll buy another with some stronger internals. I'd definitely try my hand at rebuilding the old core myself if the case isn't junk looks like fun haha.

I put the big 40k cooler on it mainly for when I'm towing the boat in the summer and hopefully to prevent any radiator failures from also killing the trans.