On my 2001 Yukon, when shifting between reverse and drive, there is a bit of a lag, as opposed to the old TH 350 or 400 trannys. As for as vehcile roll, it depends, if the Yukon is on the slightest incline, there is no roll at all, in fact, it could roll backwards. I believe the TC allows this to better enhence the coasting ability, thus helping the fuel economy. I'm not sure I would worry about it unless it feels like it slips when you apply throttle. My 2500HD works in a similar fashion, but does roll a bit better, I attribute this to more engine torque due to the 6.0 versus the 5.3. If either had the 4.3 I could see even less roll.

 

Wow.

I’ve experienced both the lag and the whine with my just acquired Blazer as well, and both were causing me to worry about the transmission. Then I assumed the whine was just the 4WD drive train, and the lag does seem more prevalent the colder it is, and seems fine otherwise.

 

Sorry guys, I was out of town. New problem noticed for me. Ever increasing my thought that the tranny is messed up, this weekend on I-40 the thing would not come out of 3rd gear. As I was cruising at 75mph it was turning around 3500 rpms and the whine was very audible. The truck was not cold and had been running for around a half hour before jumping on the interstate. While driving I manually dropped the selector into 3rd and of course no change in RPMs as I was already in third. I then put it back in overdrive, and kicked it trying to make it drop down a gear. It wouldn't. I slowed to about 55 where I am pretty sure flooring it would normally make it drop to 2nd. Nothing. It stayed in third and kinda bogged along. I took it up to about 75 and put the cruise on as I felt maybe I was pushing too hard on the gas. It stayed in 3rd.....for several miles. Then I exclaimed to my wife I was glad it was doing this as now I could finally take it in with some pretty hard evidence something is wrong. About a minute after I said that it dropped into OD and settled just over 2000 RPMs. I have put about 400 more miles on it since then and it still has not become stuck in 3rd again. Does anyone know what could be causing this?

 

I highly recommend you take it into the dealer. Even if they don't find the problem right away, you have documentation saying this is an issue. Besides, more then likely thay have TSB on the problem.

To me, it sounds like you have a fluid flow problem, not enough pressure.

 

Yeah you are right Hanr3. I do need to get it documented. I just wanted to have some hard evidence b/c last time they said everything checked out fine with it. I doubt they even messed with it.

 

The problem with ANY shop doing work, they completely reset the transmission computer (in GM vehicles the PCM handles this) and then they check the CVIs (clutch volume indexes). In an electronic tranny, the pcm modulates the CVIs to maintain pressure to the clutches, but only enough pressure to keep them from slipping. The problem with reseting the computer is that it generally takes the tranny awhile to relearn the CVIs so they won't be the same as they were when you drove it in to them acting up.

Chrysler is FAMOUS for doing this with their crappy 42LEs in the LH vehicles. Those trannies will act like new for about 20-30 miles after a reset, but after that, they'll slip and go into limp home mode where P,R,N,&2 gears are the only ones you can use! Other manufacturers are catching on. It's troubling to say the least.

 

Awesome. I guess that explains why I thought it felt a little better when I got it back last time.

 

UPDATE: Good News, Bad News

Well, it turned out it was low on fluid. They had told me they had checked everything before I picked it up, so I assumed it was fine. DOH !

Anyway, that solved the problems I had with the lag in the gears engaging and the high revs required to first get it moving in REVERSE.

However, days later, after pulling out of a parking lot and heading home, I all of a sudden had no DRIVE or OVERDRIVE. The FIRST, SECOND, and REVERSE gears are just fine. Tight, snappy, no lag, no slippage. Solid as a rock. And there was no prior indication in the DRIVE and OVERDRIVE gears. No slippage, or anything else weird. Just as though somebody had flipped a switch.

Now, I had just earlier came from visiting a relative who lives out in the rural sticks, and their driveway has some pretty bad ruts and high middles and I had scrapped a few times going in and out. My first thought was that I had cracked a line or disconnected a wire, but from what I could see, everything is above the skidplates and I saw no leakage. I want to check it again when I can jack it up.

Is it possible that I disconnected an electrical connection, given that the OVERDRIVE is electrically operated on the 4L60E, right ?

Also, I’ve never seen a dipstick that was so difficult to keep from smearing, making it hard to read right after adding fluid. That tube has a heck of a bend in it.

 

Well whitt, if you find my updated post about this issue you will see that my dealer tore into my transmission and pretty much completely rebuilt it for the stuff you were talking about. They said "it has burnt reverse clutches and maybe a belt". Anyways it has been there a week tomorrow and though the transmission is done, they have some wind noise yet to fix. Will let everyone know the final outcome.

 

This is the exact reason why you should only keep ONE thread about your problem. From now on, Update threads will be removed.