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4L60-E Tranny failure

uconnjack

Full Member
Joined
Mar 23, 2015
Messages
13
Hi, I have a 2008 4WD Avalanche with about 130K miles and (I assume) the 4L60E transmission.  We just drove it from CT to Orlando with no issues, but while driving it on International Avenue, heard a loud bang/clunk and lost transmission engagement (in Drive).  Coasted into a gas station, turned the car off and back on, and started going through the gears.  Drive or 3rd wouldn't engage, but did engage in 1st and 2nd.  Drove forward in 1st then 2nd, hear another clunk/bang (not as loud), and then Drive and 3rd "worked" again (except I think it was still in 2nd gear).  However, now Reverse won't work (feels like there is resistance, but won't move), and is actually engaged and moves forward while in neutral!?!  Wasn't far from the resort so was able to limp back in 1/2 gears. Noodling around, I am seeing a broken reverse band or sprag or maybe solenoids, as possible culprits, but none seems to totally fit, but then again, while I can do most of my own mechanical work on my car, tranny's are out of my wheelhouse.

Before I bring it to a shop to get diagnosed, I was hoping someone could help educate me on the 4L60E and/or give me some ideas what the issue may be so I can discuss it intelligently with the mechanic, generally understand their diagnosis, and make sure I don't get ripped off.

And if anyone here is from the Orlando area, any advice on trusted/reasonable mechanics would be appreciated.  While I would normally not go to them, I am also thinking whether I should go to a chain store transmission shop or a dealership so I might have some recourse if I have any future problems with a repair once back in CT.  Thoughts?

Thanks in advance!
 
Can't help on the tranny issue, but a lot of members replaced theirs with a Jasper tranny
 
My transmission went out at around 125K.

I had it rebuilt at a local transmission shop.

I did not specify any special do-dads to be installed during the rebuild.

That rebuilt transmission and new torque converter now have close to 100K miles on them.

So far, so good.

(y)
 
How much did it run you?

EXT4ME said:
My transmission went out at around 125K.

I had it rebuilt at a local transmission shop.

I did not specify any special do-dads to be installed during the rebuild.

That rebuilt transmission and new torque converter now have close to 100K miles on them.

So far, so good.

(y)
 
Around $2000 six years ago.

(y)
 
EXT4ME said:
Around $2000 six years ago.

(y)

Mine was somewhere around this I know more 3 years ago. That was shift kit, upgraded parts (would have to find invoice), new torque converter.
Had to have the Avy flashed at the dealer they told me they would of beat his price with same up grades. 
 
Sounds like the sunshell and/or spline shaft.

Upgrade options are "the Beast" and the Sonnax "Smartshell". Of the two, I recommend the Smartshell. The Beast is a much thicker material than stock or  the Smartshell, but the Smartshell comes with a redesigned planetary bearing that redistributes a lot of the load, transferring it to the carrier from the bearing and while only slightly thicker than stock, it's made of stronger material.
 
uconnjack said:
Noodling around, I am seeing a broken reverse band or sprag or maybe solenoids, as possible culprits, but none seems to totally fit, but then again, while I can do most of my own mechanical work on my car, tranny's are out of my wheelhouse.

Before I bring it to a shop to get diagnosed, I was hoping someone could help educate me on the 4L60E and/or give me some ideas what the issue may be so I can discuss it intelligently with the mechanic, generally understand their diagnosis, and make sure I don't get ripped off.

Well, there is no reverse band and solenoids wouldn't cause a bang, but really what it is doesn't really matter.  At this mileage and with this internal damage you need a rebuild and the best route if you aren't going to do it yourself is to get a rebuilt tranny.  Jasper is a good choice but there are others, including GM. I've heard costs from around $2K to $3K for tranny replacement, including labor.  Never good to need this kind of repair away from home - good luck.
 
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