Possible Slip in overdrive? [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Possible Slip in overdrive?


elementkidd
11-24-2010, 12:54 AM
So I was driving on the highway (50-55 mph) and i noticed my RPM's were jumping around about 100-400 rpms in overdrive.... The car has 178k miles on it, I really hope its not the transmission slipping but thats about all i can think of...It really is only noticeable in overdrive but it may do it in 3rd gear too... I drove the rest of the way home in 3rd gear because i didnt like the feel it was making in overdrive... I do have 31 inch tires on it but I think the tranny is about done for...

SparkyJJO
11-24-2010, 01:20 AM
Actually, it may be related to the torque converter lock not locking. I don't know about these later 4L60E transmissions, but I know the earlier ones (circa 98) had an issue where the TCC valve and/or valve bore would wear and then not keep the TCC lock properly. This would cause RPM fluctuation, or complete loss of TCC lock altogether. Bad on the trans in the long haul as it would run hotter, and also hurts mpg.

My 98 Camaro had that issue. I installed the Transgo SK-4L60E kit which is a simple transmission shift kit that fixes the TCC lock up problem, plus a few other fairly common things that can happen as well (rough 1-2 shift, a double-bump shift, few oddball things like that). Worked flawlessly.

I'm actually going to put the kit in my TB this weekend, as a preventative measure. Since it also speeds up the shift time a tad, it reduces slip, and theoretically reduces wear. The 4L60E in my 98 Camaro has 161k on it and works just fine.

elementkidd
11-24-2010, 01:26 AM
Actually, it may be related to the torque converter lock not locking. I don't know about these later 4L60E transmissions, but I know the earlier ones (circa 98) had an issue where the TCC valve and/or valve bore would wear and then not keep the TCC lock properly. This would cause RPM fluctuation, or complete loss of TCC lock altogether. Bad on the trans in the long haul as it would run hotter, and also hurts mpg.

My 98 Camaro had that issue. I installed the Transgo SK-4L60E kit which is a simple transmission shift kit that fixes the TCC lock up problem, plus a few other fairly common things that can happen as well (rough 1-2 shift, a double-bump shift, few oddball things like that). Worked flawlessly.

I'm actually going to put the kit in my TB this weekend, as a preventative measure. Since it also speeds up the shift time a tad, it reduces slip, and theoretically reduces wear. The 4L60E in my 98 Camaro has 161k on it and works just fine.

Where can i find this kit and how much? Just to keep it in mind

efi-diy
11-24-2010, 07:44 PM
Try this ...

In OD on the highway with constant throttle, lightly rest your foot on the brake pedal enough to turn on the brake lights but not enough to engage the brakes. This will force the TC to unlock. Watch the tach.

Report back what you find.

SparkyJJO
11-24-2010, 09:29 PM
Do the test above first.

It is the Transgo SK-4L60E kit. Costs $40-50. Takes a little bit of work to install but it is not too bad. I wouldn't recommend doing it if you don't have some prior experience working on your truck (aside from oil changes or whatever). But a shop could install it for you if you wanted instead.

envisionelec
12-30-2010, 07:44 PM
Try this ...

In OD on the highway with constant throttle, lightly rest your foot on the brake pedal enough to turn on the brake lights but not enough to engage the brakes. This will force the TC to unlock. Watch the tach.

Report back what you find.

I read this thread before driving out of town this weekend. I took video of the problem, but decided to reply to this thread first with my results. I can post it if you'd like.

At 55MPH, and about 1800RPM, the tach bounces about 500RPM with a noticeable lugging feel. I pressed the brake while holding the accelerator and the transmission downshifted and the tach rose to 2200RPM. The lugging/bouncing went away. It is a repeatable situation, most notably on an uphill grade when you'd expect an initiated downshift. If I goose the accelerator, it will downshift. It just seems to hunt indefinitely if I let it.

My truck has 205K miles and has an extremely detailed service history including fluid changes. It drives like new, otherwise. :woot:

bradster1
12-31-2010, 09:40 AM
Hey guys. I'm definately no expert on this but what you are describing is exactly why I am in the middle of replacing my wifes tranny in her trailblazer right now. Which is why I started the post below. I took her's in for this exact same thing. The mechanic who is highly regarded for his tranny work told me the tranny is just starting to go out in it. He explained to me how the plates start slipping or something and then it just gets worse from there. He quoted me $1700 + tax for removal, rebuild, and installation. So I found a used one with 70k on it and am doing it myself. I hope I am not making you feel bad and I could be totally wrong too. Good luck.

envisionelec
12-31-2010, 07:07 PM
I found this over at another forum (gm-trucks.com)

My last truck was a 99 1/2 ton 4.8L with the 4L60E, I had the same problem. No trouble codes were set, so I took the dealers tranny guy for test drive, he brought along his tech 2 scan tool. As we were driving I told him what exactly happened and when. He picked it up on his scan tool right when I said it was going to pop out fo OD.
The problem was two fold, part of the problem was the tcc solonoid, the other half of the problem was the port on the valve body where the tcc solonoid seals off. See, the tcc solonoid is sort of a proportioning valve, it has a steel ball that opens and closes and that steel ball seals off on port in the aluminum valve body. See where I'm going here, , steel vs. aluminum? Any way, the steel ball starts to peen away the surface of the aluminum valve body, when the fluid gets warm (that's when mine did it) the fluid thins out some and leaks past this "improper" sealing surface and it messes with the line pressure.
The fix - the dealer pulled the vlave body and took it to a machine shop where they reamed out that port, installed a steel insert, so now the steel ball in the tcc solonoid can seal off on steel surface. $450.00 problem solved.

This seems very plausible...and not a major overhaul just to "look".

elementkidd
01-10-2011, 05:35 PM
sorry everyone i have been away from the computer for awhile... Ill give you an update on what my envoy has been doing...

Took it to a well known tranny shop in town, said there is a screen on the solenoids and sometimes they get clogged, so he suggested a flush. So we had it flushed.

Fixed the problem for about 1,000 miles or so and now its starting to do it again. I will try the 55mph and slightly breaking in a few hours when i run to Walmart. Im just stuck between, is the tranny going out/or is it just a small problem.

My cousin had a 02 trailblazer (same gear ratio[i think the 3.42...what ever the highway gear is]) and his always seemed more peppy to the throttle then mine ever was.

elementkidd
01-16-2011, 07:07 PM
Well i was on the highway a few days ago and tried the, keep at steady speed/rpm and lightly hit the brake lightly so only the lights come on and this is what i got.

http://www.youtube.com/watch?v=AOLbvDFDS8I

It seems to jump up about 200 or 300 rpm when this is done, Any thoughts?

trailblazer02
01-16-2011, 10:03 PM
Its your torque converter. Mine started doing it this past week. It's being fixed tomorrow. Good luck.

Vince B
01-17-2011, 12:51 AM
Usually most issues with the TCC on these units start in the valve body from my experience. What happens is the bore wears. You can install the transgo kit to fix this lineup or you can also pin these valves in the valve body and eliminate the pwm function for the TCC. Hope this helps. Vince

elementkidd
01-18-2011, 02:41 PM
Its your torque converter. Mine started doing it this past week. It's being fixed tomorrow. Good luck.

How much is that costing you? I drove from wisconsin to west lafayette and it didnt do it the entire time until the tranny warmed up, when that happened i noticed instead of roughly 1800rpm at 65mph it was at about 2200rpm, and it would instantly shift (really hard) into all the gears, the worst being 1st to second and then second to third and so on.

SparkyJJO
01-19-2011, 01:39 PM
Seriously look into the Transgo kit first. Many times it is a valve body issue with the TCC valve, not the torque converter itself. As I mentioned, my Camaro with the 4L60E did the same thing you are experiencing and the transgo kit fixed it. I put about 30k on the transmission after installing the kit and never had an issue again.

Even if the torque converter is going bad, the transgo kit is a worthwhile upgrade.

elementkidd
01-19-2011, 03:33 PM
Seriously look into the Transgo kit first. Many times it is a valve body issue with the TCC valve, not the torque converter itself. As I mentioned, my Camaro with the 4L60E did the same thing you are experiencing and the transgo kit fixed it. I put about 30k on the transmission after installing the kit and never had an issue again.

Even if the torque converter is going bad, the transgo kit is a worthwhile upgrade.

Never really heard of a torque converter going wrong, isnt it just a metal thing with fins in it to direct fluid in a certain way? I dont think its my torque converter. Another question, how much would a shop normally charge to put into a transgo kit?

SparkyJJO
01-19-2011, 04:03 PM
They can (and have) failed. They are pretty basic things in general so yeah they don't usually go bad, but they can.

Not sure on a shop rate. I've done mine in the Camaro and the Trailblazer myself with the help of a friend and his work's lift. Of course, he's the bigger gearhead than I am, and this tends to happen when we open it up :eek: :laugh:

I was also installing a Sonnax piston upgrade kit (replace the plastic ones with pinless metal) and a vette servo, but those aren't necessary to do. One thing I do recommend is getting a new separator plate and seals at the same time as the original plate will have some wear and the seals tend to rip when taking it apart. The whole thing parts-wise cost me under $100 for the transgo SK-4L60E kit, the plate and seals, the sonnax pistons, and the vette servo. If you do just the transgo kit and plate/seals it'll run you around $60. As always, plan on plenty of trans fluid and a filter.

http://gallery.trailvoy.com/data//506/4L60Evalvebody.jpg

elementkidd
01-22-2011, 10:14 PM
They can (and have) failed. They are pretty basic things in general so yeah they don't usually go bad, but they can.

Not sure on a shop rate. I've done mine in the Camaro and the Trailblazer myself with the help of a friend and his work's lift. Of course, he's the bigger gearhead than I am, and this tends to happen when we open it up :eek: :laugh:

I was also installing a Sonnax piston upgrade kit (replace the plastic ones with pinless metal) and a vette servo, but those aren't necessary to do. One thing I do recommend is getting a new separator plate and seals at the same time as the original plate will have some wear and the seals tend to rip when taking it apart. The whole thing parts-wise cost me under $100 for the transgo SK-4L60E kit, the plate and seals, the sonnax pistons, and the vette servo. If you do just the transgo kit and plate/seals it'll run you around $60. As always, plan on plenty of trans fluid and a filter.

http://gallery.trailvoy.com/data//506/4L60Evalvebody.jpg

And this will replace the Solenoid?

SparkyJJO
01-23-2011, 12:37 PM
It isn't the TCC solenoid that goes bad 99% of the time, but the TCC valve. If you look at the top of the picture in the bag to the left of the package with the white label and 7777ZB written on it, the new TCC valve is in there.

elementkidd
02-14-2011, 11:07 AM
Just called AAMCO in my town and they said they would replace the solenoids for about 90$ a piece. He said the whole project would cost me around $400. Should I buy the transgo kit and take it in and just tell them to install it? He said the solenoid replacement would take about 2-3 hours.

SparkyJJO
02-14-2011, 02:09 PM
Probably not the solenoids, I would have the transgo kit installed myself. I would hope they know how to install such a thing.

elementkidd
02-14-2011, 03:11 PM
Sorry for my stupidity i guess but is there a diagram that shows a solenoid and the valve body? I guess im just trying to understand the parts.

Thanks!

SparkyJJO
02-14-2011, 03:54 PM
Sorry for my stupidity i guess but is there a diagram that shows a solenoid and the valve body? I guess im just trying to understand the parts.

Thanks!

The kit comes with the diagrams and stuff. I can get pics of it this evening if you wish.

elementkidd
02-14-2011, 06:51 PM
Ok, yea thats fine, I guess i dont understand, If i replace the whole solenoid, will it replace the valve? He said it was just the stock OEM brand, or what ever they use in them now if there were any updated electronics or something. Is there a website I can go to order the Transgo kit and have it here asap?

SparkyJJO
02-14-2011, 07:25 PM
Ok, yea thats fine, I guess i dont understand, If i replace the whole solenoid, will it replace the valve? He said it was just the stock OEM brand, or what ever they use in them now if there were any updated electronics or something. Is there a website I can go to order the Transgo kit and have it here asap?

No you don't need to replace the solenoid, I'm 99% sure of that. Just the valve, which the new one comes in the transgo SK-4L60E kit.

elementkidd
02-14-2011, 07:49 PM
No you don't need to replace the solenoid, I'm 99% sure of that. Just the valve, which the new one comes in the transgo SK-4L60E kit.

Does a valve come with the solenoid?

SparkyJJO
02-14-2011, 09:10 PM
Does a valve come with the solenoid?

There is no new solenoid.

You are using the solenoids already in the transmission. The Transgo kit comes with a new valve. Two separate parts. The original solenoid in the transmission will operate the new TCC valve.

http://i58.photobucket.com/albums/g270/SparkyJJO/Car/4L60ETCC.jpg
http://i58.photobucket.com/albums/g270/SparkyJJO/Car/TCCvalve.jpg

elementkidd
02-15-2011, 06:12 PM
Thank you sparky! I ordered the kit off of ebay this morning, hopefully it will get here by thursday, in the mean time im looking for a shop that will do it for me this friday hopefully

SparkyJJO
02-15-2011, 07:45 PM
No problem :tiphat

elementkidd
02-21-2011, 12:29 PM
Had the kit installed for 380 and the kit cost 120. It fixed the problem so no more fluctuation in rpms at highway speeds... How would you know if the trq converter is going out? One thing i did notice is that at highway speeds, from overdrive it will sometimes act like it shifts down to 3rd gear, but if i put it in 3rd gear it down shifts even more, not much but the rpms do jump up a bit more.

envisionelec
02-21-2011, 02:38 PM
Mine was fixed with a transmission flush/service. The tranny had always received regular service, so I didn't figure a flush was a bad way to go.

It feels like I'm riding a rollerskate - no lugging, strange acceleration or shifts. It just rolls - a little slippery-like. It's kind of hard to explain. ;)

SparkyJJO
02-21-2011, 06:06 PM
Had the kit installed for 380 and the kit cost 120. It fixed the problem so no more fluctuation in rpms at highway speeds... How would you know if the trq converter is going out? One thing i did notice is that at highway speeds, from overdrive it will sometimes act like it shifts down to 3rd gear, but if i put it in 3rd gear it down shifts even more, not much but the rpms do jump up a bit more.

What you're feeling is sometimes on a hill it will unlock the torque converter, if there is not enough torque/power to keep it locked and maintain speed. This allows the engine to increase RPM, which increases torque and power output. Depends on the hill and all that. It feels like another 'gear' but it really isn't.

Glad to hear the kit has fixed the issue :)

spudde100
03-01-2011, 09:44 PM
So my 03 envoy had all the same symptoms as stated on here and I was pretty sure the transgo kit would fix the problem then today it got way worse. It was going through first and second and maybe third gear not sure but max speed was about 40mph and then it would go no faster. On the way home first and second started to go and finally it would not move at all. Not sure what the outcome will be. It did sound like a hose was leaking air or fluid very badly but I could not see any fluid leak. Any thoughts would be appreciated.

spudde100
03-01-2011, 09:52 PM
same 1

SparkyJJO
03-02-2011, 09:26 AM
That sounds like your trans is toasted to me.

ChevyTb2003
03-02-2011, 01:46 PM
This thread is the one ive been looking for. I have been having this issue since december.

Recently 1st gear is shifting hard but that is probably the fluid

2nd gear is perfect
3rd gear is perfect
4th gear is perfect but once overdrive kicks on i also have that weird transmission problem. you can feel the entire truck shake. So the transgo shift kit has to fix the problem. I can go 0-120 once i hit 47 the OD kicks in and it causes that weird problem. 47-73 i have the problem once im literally at 74 75 it goes away.

spudde100
03-02-2011, 07:24 PM
You were correct. Transmission is toasted. Looking at 1700/1800. Is this in the ballpark? From reading other threads it seems to happen alot with these envoys/trailblazers.

SparkyJJO
03-02-2011, 07:56 PM
You were correct. Transmission is toasted. Looking at 1700/1800. Is this in the ballpark? From reading other threads it seems to happen alot with these envoys/trailblazers.

Define "a lot"

Often times with the 4L60E (and most autos, really) it comes down to how it was treated, maintenance, usage, etc... How many miles on it? How often have you changed the fluid and filter? How aggressively do you drive? Is it all city, highway, a 50/50 mix, or..? You get the idea.

Other times it is just a premature detonation and they do go bad early, which sucks.

The 4L60E was in many GM vehicles over the years. My 98 Camaro had one and it is at 161k and no issues. Even after the previous owner managed to blow up the rear differential and the engine, the transmission survived him, somehow.

ChevyTb2003
03-03-2011, 10:44 PM
You were correct. Transmission is toasted. Looking at 1700/1800. Is this in the ballpark? From reading other threads it seems to happen alot with these envoys/trailblazers.

hey bro there is a website called www.enginesandtransmissionworld.com check that out they had a tranny on there for 741.00 with 2 years parts and labor warranty and 32,000 miles.

ChevyTb2003
03-08-2011, 11:41 AM
So i took my truck to the mechanic (transmission shop) and I told him im signed up for this forum blah blah. And the users said i needed a shift kit. I quote from the mechanic "Internet blogs are always wrong" I call him today he goes the Transmission is shuddering. and you need a shift kit. HAHA

:thumbsup: To all you smart Trailvoy members that figured this out:thumbsup:

Kudos

ChevyTb2003
03-09-2011, 01:57 PM
Actually Transmission is shot the mechanic described the pan to be as if you were to melt iron and pour it into the pan.

Transmission runs in 1 2 3 not 4 lol. ill just drive it into the ground

elementkidd
03-10-2011, 05:05 PM
How many miles were on that tranny?

SparkyJJO
03-10-2011, 06:17 PM
Actually Transmission is shot the mechanic described the pan to be as if you were to melt iron and pour it into the pan.

Transmission runs in 1 2 3 not 4 lol. ill just drive it into the ground

Uhhhh yeah a shift kit won't fix molten iron goop :eek:

spudde100
03-10-2011, 08:13 PM
Got the Envoy back yesterday with the completely rebuilt transmission. Said there was nothing I could do to prevent this one from going. Envoy has 89500 on it with regular maintanance.

elementkidd
03-11-2011, 09:58 AM
Got the Envoy back yesterday with the completely rebuilt transmission. Said there was nothing I could do to prevent this one from going. Envoy has 89500 on it with regular maintanance.

Only 90k WOW i have more then twice as much on mine, I guess you just got unlucky! Glad to hear your back on the road, Even though that means you have to pay the redic gas prices.. 3.60 here :hopeless

ChevyTb2003
03-11-2011, 04:57 PM
How many miles were on that tranny?\\


126,118 miles on the tranny. But was rebuilt at 66,000

ChevyTb2003
03-11-2011, 04:59 PM
Uhhhh yeah a shift kit won't fix molten iron goop :eek:

hahah yea bro. so I am a Proud new owner of a transmission with 33,000 miles on it $745.00 Not bad eh? Free shipping 2 year warranty Parts and labor :O:thumbsup:

Gonna sell the core on my old tranny see what i can get for it.

Bigdog645
12-23-2011, 01:01 AM
My had same problem. It was spring. Cost only 200 to fix work great

John Weaver
01-08-2012, 11:49 AM
my trans started to have problem when shifting from 3 to4 or 4 to od. felt like it was not shifting into gear or just lasting to long on the change over. in shop now needs to be pulled completely out and then checked to see what the problem is all that i know is there is a problem. 32000 miles can not understand what the heck it could be. could it be like the other tb owners on here just a valve body or do you thing something more. times are tight now i dont know a lot about tranns so i hope i dont get shafted on the cost... i will respond as soon as i know what they tell me. any pointers will help. :thx

John Weaver
01-22-2012, 01:22 PM
problem with my tb is a delay shift 3 to4 gear and was told that it is normal i think that is bs. anyone have a idea of how to fix this problem... all will be helpful. thank you....

joedutt
02-27-2014, 03:27 PM
I donít post but I do a lot of reading here. I have learned a lot from this group. You guys are great. I have learned so much here. I even learned how to change my burned out dash board and radio lights.

Now I have a new pickle. At 178,800 my 2004 Trailblazer just started searching for "where it should be" at 1800 to 2200 RPM and 45-55 mph (no major pull on the engine) I ran a search on trailvoy and BINGO! My mechanic said "well that sounds like it and yes I can flush your transmission and put in a kit for you".

Now I have the dumb driver question. I have the in-line 6 with the towing package 4 speed transmission with overdrive. How do I know if I have the correct transmission for the Transgo SK-4L60E shift kit?

Whatever your answer is, I will try to read slow enough to understand it.

Thank you,

Joe

mjghunter1
09-30-2014, 02:12 PM
My 2004 Envoy just started with the rpm jumping at 65 mph. It has 174,000 miles on it so, I dont feel so bad about it. Going to change the tranny oil and filter to just see if it helps. Probably have around 80,000 miles on the oil. This is a great site, I wish there was one out there this good for toyota.