2007 Sierra Classic Transmission Failures

willywinter · June 19, 2013

Hi Everyone--

First off, I really love the GM-Trucks forums, there's some really great content here and I've enjoyed the reading! Having said that, this is the first time that I have posted but that is mainly because I have a problem that I just can't seem to get to the bottom of.

The Vehicle: I purchased a new 2007 Sierra Classic SLE Extended Cab 4x4 with the 5.3 in January of 2008. It currently has 120K miles on it and has mostly seen a mix of in town and highway driving with very little towing. I tow a two place aluminum snowmobile trailer a dozen or so times a year and that's it. Another point I should mention here is that I am not an aggressive driver and don't beat on the truck at all.

Exactly one year ago (at around 100K) i lost overdrive on the highway. Soon after things began deteriorating pretty quickly so I brought it to a local rebuilder who came recommended from several friends who run repair shops. I had my 4L60E rebuilt and also purchased a 3 year 36K Warranty. Lets just say that in the last year I have had two more rebuilds each taking several weeks to get done and failing within 3 months. Finally, I insisted that the shop purchase and install a different 4L60E from a major rebuilder which they did. After that, the truck really shifted great--like new even.

Well here we are, 1 year later after the first failure.. tonight on the way home driving normally in traffic I had full slippage in 3rd.

I am at a loss at this point to be honest. I just don't understand how this could be happening and have really lost faith in the brand that I have always been a loyal fan of. I simply cannot deal with the constant failures so am thinking of a new purchase--but how can I in my right mind buy a product that suffers this type of quality problem at 110K?

Has anyone experienced or heard of this type of problem before and what may be the cause? Am I expecting too much by asking for my transmission to hold up under light duty for this long? Are the L480E's better? How about the Allisons?

Thanks in advance!

Bill

Chris · June 19, 2013

The 4L80 is strong. There is a place that sells all you need to swap one in your truck. The 60 is a crap shoot. Sometimes you roll that magical 7 and let it ride in my case putting it through the abuse of a 6.0, and in your case you get snake eyes. On a stock or mostly stock engine have to go through all that. You can try a built 60. There are places that even their lowest level will suit your needs and be stronger than stock.

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KMGZ400 · June 19, 2013

i had a 4L60 completley grenade on my 03 suburban at about 115k. on the other hand im pushing 150k on another 4L60 with no issues

willywinter · June 20, 2013

The thing that is bothering me the most is that I am not driving it hard or towing anything heavy at all. I can understand if the rebuilder missed something the first 3 times but the last time I got a totally different unit that was rebuilt by larger outfit. It kills me because the truck is totally nice and runs awesome! It is hard for me to imagine there is anything external to the transmission that would be causing me to blow clutch packs like this. The truck has a leveling kit but is otherwise stock. Anyone ever purchase an L460E from the dealer? Wonder if the quality would be any better? How about other rebuilders that I can count on?

MikeNH · June 20, 2013

As others have said the 60 can be a hit or miss trans but you have a miserable streak of luck here. I'd be curious to see temperature trends of the trans (this would require a new cluster or a third party tool to monitor trans temp). What kind of failures are you getting? Does the rebuilder do any sort of failure analysis? The trans can go the distance, a friend of mine has a 2002 with like 220k on it. He had the trans rebuilt just before 200k when he got a new boat as a precaution.

txab · June 20, 2013

Sounds like a builder problem to me. He's missing something in his process.

Mckenzie · June 20, 2013

216,000 miles on my original 4l60e and i beat on my truck like a rented mule at times...186,000 miles on my dads 00 2wd and its shifting just fine

zach1990 · June 20, 2013

My original 4L60E made it to 276K miles. Current one is at 37K miles

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KMGZ400 · June 20, 2013

when my 4L60 grenaded at 115k, i purchased a brand new 4L60 from the dealer and drove it to 170k with no issues and a great shifting tranny..great shifting for the 4L60 that is

willywinter · June 20, 2013

I think I will see what kind of price I can get on a new trans from GM seems like folks either have great luck with these or they fail.

My first failure was a 2-4 band break. All since and I am assuming this one as well is OD clutches.

Temperature could be an issue but not sure I can explain how it is getting hot. I also wonder if it is possible the TCM is not actuating the shift solonoids at the right time causing slippage, heat and debris to build up.

Thanks for the feedback everyone I really appreciate it.