Hey guys,
today I cleaned out the snap ring grove to 'like new' condition. While doing so, I noticed that the servo cover popping out yesterday cracked the housing on both sides of the opening used to get a screw driver under the snap ring. There are 2, one is at the 6 o'clock position: That one! Who cares? I carried on anyway! I checked the fluid level, getting it nice and hot, added 1/2 quart above full, so about 1/4" over on the dip stick.
Then I took it for a test drive, having the shorter, original pin in there...Result: it seemed to slip a bit less (probably due to the extra fluid) but still slips at about 2500rpm. No slip in '2' gear. And if I gun it like I was doing 0-60, it doesn't slip either.
Then I swapped the longer Sonnax pin back in. While getting under the pin, I took out a chunk of that cracked housing lip, say about 3/4". But I don't care, I mean at this point, right? There still is lots of lip holding the snap ring in place and nothing is leaking, so --- Carry on. Did the test drive and it still slips, probably just as much as with the shorter pin. At 2500rpm. Again no slip in '2' gear, or when I gun it from a dead stop! The only difference is it sounds like something is making a quiet whining/binding type sound and I'm wondering if the band is binding, does it make a sound? Not sure, what do you guys think? Also, I flushed both coolers for good measure, just to make sure they weren't clogged with anything.
So, what do you think?

 

What gear is it slipping in? You are sending mixed messages. You say it slips and then you say it doesn't slip. Which is it?

 

Hi, it slips in position 'D' when it gets to 2nd gear at about 2500rpm. With both servo pins (the original and the Sonnax longer pin).
But, if I have it in position '2', or if I drive it like I was doing a 0-60 - Then in both those cases it doesn't slip....

 

Let's try this way: What is the difference (internally) if in one situation you have the transmission in '2' and in the other situation you put it in 'D' while it operates in second gear? What is different inside the transmission? Is the computer doing something different in one case and not in the other? Are there solenoids or sensors involved in one and not in the other? I seem to have been told that the pressure is greater when in '2'. Why?
Thanks guys.

 

 

Ok, thanks for that. So, if we work off of that chart, the only difference is that in '2' the overrun clutch applies while in 'D' it doesn't.

 

Yes.
Which should have no affect on your slipping situation. unless by nature of some very interesting crossleaks and/or pressure rise

The next thing you need to do before we can give any decent help is to do a pressure test.
Give us pressures for ALL gear shift ranges both at idle and at 1500-2000 brake stall. (don't send your hooptie through the wall in the garage. Be safe)

 

Update:
I swapped out the longer Sonnax servo pin and replaced the original pin because I'm sure I was hearing a 'binding'-rubbing sound. (and anyway, it wasn't slipping any less or any differently, so why leave it...) While in there I noticed dark colored fluid. Obviously, something in there isn't right but I'm wondering if it could be the longer pin producing some rubbing/binding that was darkening up the fluid in the servo area...The dip stick shows a bit darker than normal colored fluid, so maybe it hasn't completely changed the color of all of the fluid (yet).
I got a measuring tape and checked the servo travel with the original pin --- 1/8" - sure it was more than that before. 1/8" with the original pin is pretty good and might explain the binding sound and darker fluid with the longer pin.
I'm working on doing a pressure test, had to get a 6' hose for my gauge to keep safe. Taking a bit of a long time because I had to remove the front driveshaft and maybe even the neutral switch and I ran out of time today. Try again tomorrow. Call me overly optimistic but I still have hope for this transmission. Time will tell...
Thanks for all of your help guys!

 

Keep messing around with that transmission and poking around the automatic section and when it officially becomes time you will be rebuilding it yourself

 

If it has 1/8" of travel...or anywhere near that ballpark...it is NOT binding in 2nd

I've experimented with band clearance as tight as .030 in a 60e. all the way up to .150

.060 is now my target on all performance builds and .080 on everything else.
1/8 is HUGE clearance when compared to the point at which it binds

 

I believe it is officially time.

 

Thanks Man, I will.
I have a deal on a used working 4L60e from a 2004 Envoy 4X4 and mine is a '05 6L Vortec. Mine has starter position at bottom right and the Envoy has it at top left on the bell housing. Am I right to think that for a swap all I'll need to do is swap bell housings between the two?
P.S. Don't take that to mean that I'm throwing in the towel, cause I ain't! That transmission in my truck had me walking by the side of the road and trying to get a cooler line to hold until 5 in the morning covered in tranny fluid. Trust me, I'm not finished poking the sides of this transmission just, just yet!

 

Yeah, I agree. But remember that 1/8 is with the shorter pin, and I think it sounded like binding or rubbing sound with the longer pin. But I remember that I had good travel with the longer pin so it probably isn't a binding issue.it could also be something else that has started rubbing. But I like to put down my observations daily as I track through this issue. That way I'm less likely to forget a minor detail and if ever some poor soul stumbles upon this here thread well, either we'll send him along with a proper functioning transmission or he'll be checking into the asylum. Poor Buggar...And he was so quiet too!

 

I hope you're wrong...Driving me to drink...

 

Alright, here are the numbers. I did 2 tests one a few minutes later than the other because I was getting different numbers the second time. The first number is at idle, second is about 1500rpm. The left row is first test, the right row is second test a few minutes later:
P - 75 & 75 --- 85 & 85
R - 80 & 300 --- 140 & 275
N - 60 & 60 --- 60 & 75
D - 95 & 225 --- 115 & 230
3 - 80 & 225 --- 115 & 230
2 - 90 & 185 --- 100 & 215
1 - 90 & 225 --- 115 & 250

 

Please let me know what you think of these...And if you can spot any reason why '2' works perfectly and 'D' slips at 2500rpm...And also, on 2 different occasions the lower cooler line has popped out on the highway. Related?

 

My transmission has often run on the warm/hot side. I don't have the exact temp, but into the 200+ range (over halfway up on the guage, maybe even 3/4), with very little load placed on the truck (no towing etc.) after a bit of city driving for say 10 minutes or so. I'd notice it at idle, when we're at a drive through for example. I drive a similar Escalade of the same generation and it doesn't get as hot, never passes the halfway mark on the gauge.
Also, at what RPM would my WOT be?

 

Well, guys, the saga continues:
Today, instead of revving it the driveway, I set it up so I could do a real road test with the gauge still hooked up. Here's what I found:
While in 'D' the pressure (in first gear) stays around 125psi, then the same for the first half of second gear, as it continues climbing in rpms at about 2200 rpm (right when the slipping starts) the pressure drops to 65psi (give or take) - maybe this would explain why the longer servo pin didn't help stop the slipping issue.
While it is slipping in 'D' if I move the gear shift lever to '2' the pressure goes back up to 125psi and the slipping stops.
When driven in '2' the pressure is pretty much always around 125psi. and there is no slipping.
Any ideas?

 

A. what do you mean "halfway through 2nd"
B. have you watched PCS amperage. Both commanded and actual? If the amperage changes and that correlates to the pressure drop. You can chase that electrically or in the tune. If the amperage does not change, you have a pretty massive internal leak. I'd have to start looking for leaks in 2nd gear while in D4 shifter position that are not possible in D2 position
C. I'm guessing that these are pressures at light throttle. Just cruising? Because if these are heavy throttle pressures you're going to be rebuilding this thing quite soon

 

Hi, thanks again for your help.
A. - What I mean by halfway through second is this: picture that you are accelerating normally from a stand still to 45 mph, it will go through first gear, shift into second and it will be going through second gear about halfway up --- as the rpms hit 2200 --- (that's the halfway point I'm talking about) --- it will start to slip and rev.
B. - Other than the psi gauge I don't really have anything in terms of equipment to see what is happening internally. I guess you were referring to a sophisticated scanner...As far as the leaks, yeah something is leaking in 'D' that isn't leaking in '2' or some electronic component that only kicks in on 'D' is cutting out halfway through the gear. (Pressure sensor, force motor, shift sensor etc.)
C. - Yes, only at light throttle. If I gun it, everything works just fine all the way through the second gear.