Transmission Problems On 4l60e Equipped GMC Truck

[Mike Diaz]

I've been in the repair business for the past 7 years, including almost 3 years as manager at a specialty transmission repair facility. I thought I would share a few of my experiences with the GM drivetrains.

 

The 4L60E transmission was one of our most repaired transmissions when I ran the transmission shop. The biggest problem I dealt with was the loss of 2nd, 4th, and reverse. Most people thought they needed a complete rebuild when they brought their truck in, and 9 times out of 10, it would only be the "reaction sun shell" which is a $30-40 part from Transtar (www.transtarindustries.com). One of the biggest causes of the sun shell gear breaking is somebody shifting into reverse while rolling forward or trying to rock out of a situation where they were stuck in snow or mud. It puts a lot of stress on a small gear, and it can either strip out or break. You should always stop completely before shifting from drive to reverse (and vice versa). A reaction sun gear replacement should cost under $1000 including labor. The transmission must be removed to replace it.

 

One of the other problems that I found on the 4L60E transmission was overheating from towing. If you tow, you should definitely consider getting a Hayden(or comparable) transmission cooler. Your torque converter takes a huge amount of abuse when you're towing and also put out a large amount of heat. If you drive hard, this should be one of your first modifications to the truck. If you overheat a transmission bad enough, you most definitely will be rebuilding that transmission and torque converter. Expect a $1500 to 2000 bill. Possibly more if you drive it until it stops.

 

Another common problem I found on the 4L60E transmission was the solenoids going bad. There's no rhyme or reason as to why they go bad, but they do. The Electronic pressure solenoid (EPC) was the most common, and can cause slipping, overheating, and a check engine light. The cost to repair the solenoids was usually under $500. Always replace all the solenoids, never just one.

 

Typically, during any type of service where the transmission pan needs to be removed, the filter should be changed.

 

The last common problem I found on the 4L60E transmissions was a boost valve leaking internally in the valve body. The boost valve would bleed off pressure that is needed to properly engage the clutches and the torque converter. The fix is a "boost valve boring kit" that reams out the valve bore, then you install a larger valve. This is another major cause of overheating within the transmission. Most of the time, a transmission cooler will not help this problem. Typically this is a $300-400 repair.

 

 

That's all I have off the top of my head, if anybody has any questions, feel free to ask, I still have my rebuilder's phone number if I get a questions I can't answer.

[satori]

Good info. Does tromping the gas from a stop put as much stress on the reaction sun gear as shifting between reverse and drive while moving?

[dlstewart01]

Hell, I put mine in reverse doing 55 one time. It wasn't in there but a second and I'm still hoping I didn't screw something up. Has worked good sence then.

 

If you must know I was going for N and hit R.

 

 

Don

[97SierraGMC]

i think from now on i am going to make sure i completely stop before going in and out of reverse

 

btw what was the charge if you took the transmission out yourself and put it back in?

 

and would you recommend a filter change even though the fluid looks good and has a good smell? on a truck with 128,000 miles

Edited August 29, 2008 by 97SierraGMC

[Zembonez]

Good info. People with first hand knowledge of these things are always welcome. So far I have not experienced one single 4L60 failure (and I hope I don't) but I'll be the first to ask if I do.

 

Thanks.

[yv1650c]

I have a 2008 NBS does it come with 4L60E ??

[Outbacker]

I was talking to my local tranny shop about tranny temps when towing, noting that mine climbs to about 195-205 degrees when going up hill, and then leveling out about 186 during steady towing, and he told me that was acceptable. I then asked about synthetic oil in the tranny and would it help. He told me that he has not been sold on the synthetic oil as he has not seen enough evidence where it should be switched from dino oil. He also recommended a oil change yearly in the tranny if towing on a regular basis. I think that when I do take it in, I will most likely switch to Mobil syn oil in there. Any thoughts?

[VMax2007]

What's your opinion on the 4L70E? How does it compare to the 4L60E? How much more "Heavy Duty" is it? Does it experience these same issues?

 

Any opinions on the 4L70E would be appreciated.

 

Thanks!

[VMax2007]

I have a 2008 NBS does it come with 4L60E ??

 

 

Unless you have the 6.0 engine, yes.

[Mikeee]

Welcome Mike !

 

Where ya been ???

We've been waitin' years for a trans guy.

 

Now we need a:

motor guy

A/C guy

'puter guy

steering wheel guy

front end guy

brakes guy

rear end guy

tires guy

electrical guy

truck wash guy

body guy

paint guy

fuel system guy

 

Who else do we not have?

[jrrod2004]

Welcome Mike !

 

Where ya been ???

We've been waitin' years for a trans guy.

 

Now we need a:

motor guy

A/C guy

'puter guy

steering wheel guy

front end guy

brakes guy

rear end guy

tires guy

electrical guy

truck wash guy

body guy

paint guy

fuel system guy

 

Who else do we not have?

 

 

 

 

uhhhhh a BEER GUY!!!

[Zembonez]

I have a 2008 NBS does it come with 4L60E ??

4L60E is the common trans unless you have the 6.0.

 

He's not saying that they are junk... just pointing out the things he has seen go wrong with them. Keep in mind, the tranny guy only sees the broken ones. This is not necessarily an indicator of the transmission's quality.

 

No panicking guys. The sky is NOT falling.

[C & A s Dad]

Mike, we really do appreciate the info and I am with you 100% on the heat and cooler. Did you use Hayden's stacked plate design coolers? This is what we attempt to sell and recommend from our stores. All info indicates they are much more efficient and flow better than the old style tube and fin coolers.

[nbscanuck]

Welcome Mike !

 

Where ya been ???

We've been waitin' years for a trans guy.

 

Now we need a:

motor guy

A/C guy

'puter guy

steering wheel guy

front end guy

brakes guy

rear end guy

tires guy

electrical guy

truck wash guy

body guy

paint guy

fuel system guy

 

Who else do we not have?

 

 

 

 

uhhhhh a BEER GUY!!!

 

 

pizza and wings guy

[georgerosen06]

what about if you put it in neutral till you stop then put it in drive?