Hi guys, I have a question for you, please: My 4L60e had a cheap, (rounded off tip) lower cooler line that popped out mid-trip on the highway, losing a lot of fluid. I stopped, put the line back in, and added a few quarts of fluid and wanted to limp it home. Got it moving forward again, but it did it again a few miles up the road. The little f&?%er felt solid but kept popping out while driving. Anyway, it took about 3 tries like this, then I used tie-wraps to secure the line in and I finally got it home. It seemed to be slipping a bit but at 4 o'clock in the morning after a 10-hour work shift, who really cares? I have since changed the tip, using a newer, more squared-off tip that will be held in place securely by the C-clip (but I'm thinking of leaving the tie-wraps for good measure). Now, she slips in 2nd at about 2500rpms and will need to go to 4500-5000rpms to shift to 3rd when in 'D'. If I move the lever to '2' she's fine, no slipping at all. I haven't tried highway speed yet to see how she acts in '4' because I don't want to drive it too much before I know what is wrong with it, I'd like to avoid doing more damage. What do you think, where should I be fixing? Thanks for any help that you can provide. Have a good day.

 

Sounds like your 2/4 gear band wore down; it likely was already well worn and this was the final straw.
Generally, when the band wears down, the trans will start to slip in 2nd gear; later it will also slip in 4th gear.
So, it sounds like time for a rebuild.

I have documented how to lengthen the servo pin to get a little more life out of the band, and members have had success with it, perhaps giving them another 5-10,000 miles before finally needing the rebuild.
However getting the servo pin out of a trans in a Gen 4 is a challenge; I think some people removed the driveshaft and trans mount and by then lowering the back of the trans/engine combo they were able to remove the servo.
(On a truck it is easy to remove the servo assembly from the trans.)

 

Ok, thanks for the reply. Full disclosure here: It is a 2005 Escalade. I posted on the truck forum, didn't get any valuable answers and it is obvious that the guys here know their 4L60e inside and out.
Sonnax makes a longer servo pin Part #77787-02K - and I have seen that there are 3 different length pins possible from a shop manual. I also know that some guys soldier the pin longer and take measure of the movement (which is all great and easy if tranny is on the workbench). What I wanted to know is this: Say I order the Sonnax pin and throw it in, knowing my pin isn't creating enough 'tightness' on the band, is there any way that I can do more damage if say that Sonnax pin puts too much 'tightness' on the band? I'm not really equipped to measure the .025"-.075" movement in the servo and I'd like to do the job without removing said tranny....Thanks

 

Good to hear that you already know about the longer servo pins.
First the suggested servo movement is .075, but I round it to .065 to .125 which is 1/16" to max of 1/8". It is reasonably easy to estimate and I strongly suggest you do that now to confirm excessive servo clearance due to band wear.
While holding a ruler near the servo cover, press on the servo cover with a crowbar. Very likely you now have more like .250 (1/4") movement at which point the band starts to slip.

 

I did use a pry bar on the servo cover and much to my surprise, it seemed stiff and had very little movement. At first, I actually thought that it was seized. Now, it moves more freely but not a whole bunch. So, I'll get under there and see if I can estimate the movement.
Also, any idea why it doesn't slip when in '2'?
Thanks

 

Sorry, I missed some details in your first post; I saw the "Now, she slips in 2nd at about 2500rpms" and therefore think band. I missed you saying the it doesn't slip with shifter in D2.
If you are sure when shifter is in OD/D4 that it is slipping 2nd and not already in 3rd, then I am not sure; it could be that the PCM commands more pressure in D2.
Determining the servo end play is helpful information in any case.

Actually the first step is to check the fluid level; it is easy to misread the level. Just to be sure, the level is checked with the engine running. Many people have reduced slippage problems by overfilling by a 1/2 quart; therefore a 1/4" above the Hot/Full line is a good goal.

 

Mrvedit,

Ya know, I have really been impressed by how active you have been... and also impressed that you have been passing on some solid information!

Thanks for becoming so active here again.

 

Thanks for the great reply. I will double check my fluid level tomorrow and I'll get it to 1/4 quart over full and take it for a drive. Let you know. I'm never exactly sure when the transmission fluid is at 'hot', unless I check it at 'cold' and then go for a longish drive, then come back and check it at 'hot'. But, just checking in the driveway, for some reason, I would think that it has to idle for a long time before getting to the temperature considered 'hot'. I'm not exactly sure if it is in lockstep with the engine temperature either, or can the engine temperature be at running level and the transmission, having just sat there, still be much cooler...

Also, I've been thinking about my own question regarding the longer servo pin made by Sonnax #77787-02K (Can you do any damage if you use a pin that provides too little travel room and is essentially makes the band 'too tight'?) I'll assume the answer is YES. Probably difficult to get the retaining ring on the servo in the first place. Jerky 1-2 shifts, and 3-2 downshifts. Continuous friction and heat. I'm sure that would be a bad scene. Fry whatever's left of the band. Probably BAD!!!

I guess the only idea that is hard to wrap my head around is measuring .075-.125" servo travel while under a vehicle with no special tools...It'd be like measuring a grain of sand with a yardstick from across the street. Basically, I'm looking to mesure a 10th of an inch servo travel. And even if I skip doing that now, with the pin I have on there at the moment, I will have to adjust the longer Sonnax pin by grinding it down to get that .075-.125" servo travel anyway...So, there's no getting around it. Thanks for any ideas that you can provide.

 

You are correct, if the Sonnax pin provides too little travel it will make the band too tight. Not enough band clearance could burn the band or bind the trans up. Again you are correct there is no way to get around measuring the travel, old or new pin.

 

It's at 1/4" of end play that the band starts slipping. So basically when you are pressing on the servo cover, you are asking yourself, does this look like a quarter inch of travel or more?

 

Here is a easy and somewhat precise way to measure band clearance. This transmission is apart so hopefully you will get the picture.

Pictures below color coordinate with digital caliper.
- Use a digital caliper (depth measuring side) and put the body marked by orange dot on the case where I also marked with a orange dot.
- Put blue to blue on the servo cover and without compressing the cover write your measurement down.
- Now do the same thing but with the servo cover completely compressed and take the measurement with the depth end. Write it down, then subtract the two measurements and you got a pretty close clearance number

 

Yes that would be precise a way to measure the servo clearance with the trans out of the car. But in a Gen4 there is insufficient space between the servo cover the chassis to use this method.
Is there enough space in a truck?

 

Hi guys, thanks for all the great replies and I hope everyone is safe out there.
I got under there today and there is no way that I can apply pressure with a pry bar and measure at the same time. So, by eye, I say that my old servo had about 1/4" play. I took it apart and I was able to remove it from the tranny without very much trouble, I was very surprised that within 2-3 minutes everything was out. Please note: This is an Escalade. I did not have enough room to pull the whole thing out in one piece, I removed the "C" clip while the pin was 3/4 way out, removed the washer and spring and took the rest out piece by piece. Did the re-install the same way. Hardest part was the final retaining clip -- PITA! But I got it!
Now, I still can only estimate the play of the new pin by eye. It looks like 1/8", about half what the other pin was giving up. What if there isn't enough play? Before I go for a drive tomorrow -- (if the pin is too long) What will be the symptoms? And could there be any damage for a short ride?
Thanks again for all of your help - You guys Rock!

 

If you have anywhere around 1/8" of travel you should be okay for a test drive. If you have any bind-up don't force it.

 

.060 is an acceptable clearance without tie-up.
So 1/8 will be perfectly fine as far as binding goes. But still wider than I ever like to see

 

Alright Boys, get your popcorn ready this one is going down as pure entertainment:
I went for a test drive with it today, when it shifted into second gear, it seemed more 'buttery' and soft type of a shift than before. It was doing fine until about 2500rpm, then it started slipping again. I continued driving it and after about 5 minutes of faster driving, I noticed the dreaded smoke it the rear view mirror. The one I had seen the first night that the cooler line popped out. The F_*&?%&*G one that is caused by trans fluid on the catalytic converter, burning. Then, lots of revving, more smoke, loss of power...etc. It was leaking all over the road. I limped it home. Looked underneath, the servo cover was missing. And I remembered, just after turning around to limp home, (while swearing) I had heard a metallic-type sound of something falling off but I hadn't seen anything in the rear view mirror. So, I went back and looked around and after 15 minutes I found it in the grass about 20 feet from the road. Finally, something good. Ain't much, but it's something!
I went home and took stock of the situation, I was missing the snap ring that holds the servo cover on but I had an extra 4L60e tranny in the shed, so not an issue, I'll use that one. I took my time, cleaned everything up, re-installed it. I figured that the snap ring hadn't been put on right the first time, so I really took my time and made sure it was snug all the way around. I took the time to try and estimate the travel distance, and I swear it seems like an 1/8th of an inch to my eye. Went to NAPA, bought MORE transmission fluid. Filled her up to middle 'cold' area on the dip stick. Decided to go for another drive, got to the stop sign at the end of my street...."Cling" --- Stop, look underneath, the F_&%**g snap ring is on the ground and I'm leaking again! Brought it right home, considered starting smoking again, but instead I wrote this wonderful, frustration-filled post. (while doing breathing exercises in various yoga positions)
So far, this transmission has popped the lower cooler line at 2 different occasions, (so I changed the line that seemed to have a rounded tip which wasn't being held in by the clip) and has popped the servo cover and the snap ring off once and popped just the snap ring off the second time. Is there any way that there could be too much pressure inside? Is that a possibility of having too much pressure?
What am I left with? Possible that the Pin is too long? If I just re-install the snap ring it is almost a mathematical certainty that it will pop off again....This situation would drive a weaker man to insanity for sure.
Any help you can offer guys would be greatly appreciated.

 

I guarantee it's not too much pressure. And if you have ANY travel at all...the pin is not too long.
Take a pick/small screwdriver and make sure the snap ring groove is clean as a whistle. Use some scotch brite after to make sure you get any debris out.
do the same with the snap ring.

Put the gap of the snap ring at 1:30 to 2 o'clock

It is easiest to use a big woodworkers clamp and put one end on the servo cover and the other on the flat spot in the case by the manual valve linkage. Squeeze the servo cover in and make sure you have your snap ring fully seated.

You're not going to like it, but 9/10 times it is an install error that causes this. The other 1/10 usually breaks the case instead of puking out the snap ring.

p.s. if this is a 2004 unit, make sure you don't have the "flat" snap ring. Normal snap ring is just a piece of round wire. The flat one will have a "double D" type cross section.
I see you posted some pics above...post some of the snap ring you're using if you are not sure if it is the flat one.

 

Thanks for the Great reply:
"You're not going to like it, but 9/10 times it is an install error that causes this." - I'd much rather know that my inexperience is the cause of my problem as opposed to defective unit. At least this way I still have a fighting chance at fixing this unit without the whole trans swap PITA....And I learned how NOT to install a snap ring on a servo cover.
And no, it isn't a 2004 unit. The snap ring is completely round and has nothing special on it.
I'll go with the assumption that if the snap ring was falling or had fallen out, the pressure couldn't build on the band and it would slip in second gear during the test drive.
Thank you, I'll post back later.

 

I still am inclined to want to figure this part out. I have been told that while in '2' the pressure will be greater compared to being in 2nd gear from 'D'. I am sure that the slip is in 2nd gear while in 'D' and while it is slipping if I shove the arm to gear '2' the slipping stops. Also, if I 'floor it' and rip hard through 1st and 2nd and into 3rd (while in 'D') with hard accelerating there is no slip. So, at that point are we sure that the pin is a potential solution? Or i there a solenoid or something that could be at fault?
Thanks Guys!

 

You are overthinking it. Lets just get the servo cover on and recheck that you have 1/8" or so of endplay. Unless your band is really worn out there should then be no slip in the 1->2 shift. Of course if the band is really worn out, it will need a rebuild.

Of course with the cooling lines popping off twice and the servo cover popping off twice, your trans might be HAUNTED !! Perhaps we shouldn't even be discussing it ?