Transmission Problems On 4l60e Equipped GMC Truck

[email protected] · September 4, 2008

Doesn't "Tow/Haul" mode disable OD? Wouldn't it be smart to use that for towing?

No I don't believe it does, it just goes into over drive at a higher RPM.

Don

the only thing i've noticed tow/haul does is hold the lower gears to about 2500 rpm under steady throttle before shifting, enabling you to apply more throttle while under acceleration w/o downshifting as easily. I have noticed zero benefit of tow/haul when engaged in 4th gear(od). I think it is a good idea but really a manual shift mode would be way better in my opinion. The current generation HD's and mega-dollar GFM rides seem to be the only people who get that feature and ironically, probably are the vehicles which need that feature the least...

[email protected] · September 4, 2008

I talked to my trans guy, who has 35+ years experience, and got some expanded info. No right or wrong about the OP ... just more information.

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.

This problem is done here all the time -$600/2wd: $700/4wd.

The actual problem is not from "rocking the vehicle" or from no complete stop from reverse to drive, but rather a problem with a vendor that did not radius the edge of the spline, but then another problem showed up with splines stripping, so at that point they were heat treated.

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.

ALL transmissions will benefit from a cooler! Is it necessary? In some cases yes.

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.

Solenoids are not anymore of a problem on this transmission than any other, unless aftermarket [China] ones are used.

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

True.

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.

This is not a boost valve as it is located in the pump. The valve in question is the TCC regulator valve, and this is normally done in this shop for $395.

Well this vendor that didn't radius the splines forgot to do it as far back as 1995/1996 on 4l65e's too. It sounds like to me this sun shell problem has been going on in GM's for nearly 20 years!!!! I was told that they were just starting to heat treat them back then. The problem w/ GM and excuses for crappy vendor products (sun shells/speedo clusters/etc.) is justy poor quality control and making crap as cheap as they can get away with.

stearno · May 17, 2009

I have a '96 Suburban with what I'vw been told is a broken sunshell(no 2nd,4th or reverse). All the quotes are for a complete rebuild, ranging from $1500(tranny shop)-$2800(dealer). I've also been told I have to have a '96 tranny and no other year is compatable. This truck is not a daily driver and I really don't want to dump 1500 bucks into it if I don't have to, so my questions are:

Can this repair be done at home, and what is entailed? (I've never done a tranny before, but am a competent mechanic)

Is there a manual for this tranny?

What parts will I need?

Is it worth it to do myself or do I just face the facts and pay the cash?

Any help is appreciated

Stearno

bigtopher · May 17, 2009

I have a 2007 gmt 900 with the HD trailering pkg does mine have the external tranny cooler? I am pretty sure it does and would anyone have a picture of what it looks like and where its at I cant seem to find it. Or its there and just not looking in the right spot. My 2004 dodge had one I could see it clear as day in the chevy thing are a little tighter. Thanks

CapitalTruck · May 18, 2009

On my GMT 800 I don't think the torque converter locks up at all in 3rd gear. I think in Tow/Haul mode it will still lock up in 4th. I have heard that the heat relative to the torque converter is caused if it is cycling in and out frequently. One guy on this board at one time installed a switch he could activate to keep the converter from engaging in 4th gear. Pretty slick I think.

CHEVIN · May 22, 2009

ok i have a question it might have already been asked but oh well, ok i want to do a trans cooler what is the best way to go? do i need more lines? how big of a aux cooler do i need? and last how do you feel about the vett servo mod?

txab · May 22, 2009

ok i have a question it might have already been asked but oh well, ok i want to do a trans cooler what is the best way to go? do i need more lines? how big of a aux cooler do i need? and last how do you feel about the vett servo mod?

If you search on here you'll find that this has been discussed several times. You'll find them quite informative

kna4977 · March 25, 2010

I have an 05 Yukon with the 4L60E that has recently started having issues in the 3-4 shift. All other shifts seem to be normal for now.

When it shifts from 3-4 it will engage, disengage, re-engage. I assume this is the TCC going in and out of lock-up??? Don't know for sure though. Anyway, it does this cycle fairly quickly at least twice before it settles into overdrive/high gear. This usually occurs around 45-50 mph under light to moderate throttle. Usually can be mimicked by starting onto an interstate where it has to go through all the gears under normal/light acceleration. Can see it do this by watching the RPM gauge fluctuate up and down as well as hear and feel it. Can usually get it to stop if I press further down on the accelerator but then it seems to lug in the high gear unless I press further then it will upshift and if I let off it may or may not do the same thing again depending on the speed. Hope that makes sense.

Another strange thing it will do is around 45 mph when it can't fully decide whether it wants to be in 3rd or 4th it will shift into third then klunk into lug in fourth. Usually occurs on back roads where the speeds are slower. Any ideas as to what is going on and how it can be fixed would be great.

Unit has 63K miles on it fluid looks and smells normal and the temperature is within normal limits. There are no service engine lights on and no codes that I'm aware of.

I've taken it to the GM dealer and they told me it was the normal function of the electronic throttle, but that sounds like B.S., plus it didn't do this when we got it 2 years ago up until a few months ago.

Is there anything I can do to get things going/point the dealer in the right direction to get it fixed? Last time they drove it they said they couldn't duplicate the problem and the electronic throttle B.S. It's under warranty until June and would like to get it taken care of before that runs out. Thanks for your help!

zedbear · March 25, 2010

I have very harsh engagement into reverse and also 2-3 and 3-2 shifts. I thought the trans could be the problem but with the front driveshaft removed, it mostly goes away. Also, driving the truck for more than 1/2 hour usually results in a lessening of this clunking/harshness.

jrrod2004 · March 25, 2010

I got a question for you:

Can I swap the 4L60E for a fortified 4L70E directly? (Drop the old one and pop in the new one)

Thanks

Z'06 · March 25, 2010

I got a question for you:

Can I swap the 4L60E for a fortified 4L70E directly? (Drop the old one and pop in the new one)

Thanks

Direct swap, just better parts!

csheatz · March 25, 2010

I got a question for you:

Can I swap the 4L60E for a fortified 4L70E directly? (Drop the old one and pop in the new one)

Thanks

Direct swap, just better parts!

Why not go with a 4l80?

jblakeney · March 26, 2010

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!!!

Consider that position filled!!

Jbo

rhett121 · March 27, 2010

I have an 05 Yukon with the 4L60E that has recently started having issues in the 3-4 shift. All other shifts seem to be normal for now.

When it shifts from 3-4 it will engage, disengage, re-engage. I assume this is the TCC going in and out of lock-up??? Don't know for sure though. Anyway, it does this cycle fairly quickly at least twice before it settles into overdrive/high gear. This usually occurs around 45-50 mph under light to moderate throttle. Usually can be mimicked by starting onto an interstate where it has to go through all the gears under normal/light acceleration. Can see it do this by watching the RPM gauge fluctuate up and down as well as hear and feel it. Can usually get it to stop if I press further down on the accelerator but then it seems to lug in the high gear unless I press further then it will upshift and if I let off it may or may not do the same thing again depending on the speed. Hope that makes sense.

Another strange thing it will do is around 45 mph when it can't fully decide whether it wants to be in 3rd or 4th it will shift into third then klunk into lug in fourth. Usually occurs on back roads where the speeds are slower. Any ideas as to what is going on and how it can be fixed would be great.

Unit has 63K miles on it fluid looks and smells normal and the temperature is within normal limits. There are no service engine lights on and no codes that I'm aware of.

I've taken it to the GM dealer and they told me it was the normal function of the electronic throttle, but that sounds like B.S., plus it didn't do this when we got it 2 years ago up until a few months ago.

Is there anything I can do to get things going/point the dealer in the right direction to get it fixed? Last time they drove it they said they couldn't duplicate the problem and the electronic throttle B.S. It's under warranty until June and would like to get it taken care of before that runs out. Thanks for your help!

My 2000 Suburban was doing this and I had a very good shop in Denver look at it and they said the tranny was fine. They suggested I check the TPS. I replaced the TPS and it fixed it instantly.

On another note. I've noticed recently when towing (first time towing with this truck) there is a definite change in tone when going up hills. The RPM doesn't move, the speed will hold but the engine sounds like it's...making more power? Does that make sense? If the hill is long or steep enough it will downshift, but before it does it will go thru this tonal change. Almost like I can hear the throttle opening more. Just wondering what it is. Thanks!