When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
2003 4L60E slow to shift when hot, Solved 12/18/17
*************Problem found, my error on installing a valve body sleeve. **************
Hello forum members and gurus. I have been searching and reading for a few weeks here and learned a lot, so finally decided to join even if I don't have a LS power plant. Seems that you guys have the most information. I have been driving a 2 door junker Honda for 14 years and letting the wife get all the new cars to tote the kids around in. I came across a $200 2003 2WD trailblazer at work that the customer from Georgia didnt want to fix. I live in Virginia.
It did not move in any gear or rev. I tore it down and the oil pump slide and rotor was trashed. OK easy enough, I'll rebuild it instead of $1400 for a 3yr, 100,000 mile warranty from GM through work from a powertrain dealer in Texas. Absolute best prices I have found and easy to work with. Anyways... I watched Transmission Bench's 20+ videos a few times a few weeks before even going into the trans, and when i used to work in the shop before moving to parts dept at my dealer, I had helped the senior top guns work and watched and learned what I could. Also I watched Automatic Transmission 's videos a few times too. Hiram knows his stuff. But that did not teach me about symptoms and problems I could have created on my own. So anyone who is still here reading....
I rebuilt the transmission without knowing any other symptoms or problems, I just looked for scoring, burnt clutches, etc. After rebuild it shifts and holds gears great. Once it has been driving a while it is slow to shift or will not shift until you let off the gas to let it slide into the next gear and then it holds. 1-2 and 2-3 shift. In addition to no overdrive. (but 4th is there when 'cold'. it takes about 10 minutes, maybe less to get it to act up, but every morning its fine until warmed up). But it does have a slight 2-3 flare shift as well when 'cold'
what I replaced:
Transtar overhaul kit with bonded pistons, steels and fibers and seals.
WIT reman pump
GM torque converter, spacer plate, shift solenoids and manifold pressure / temp switch, pan gasket and filter
WIT standard 2-4 band
WIT aluminum pistons 1-2, and forward in VB (3-4 was already alum)
Sonnax TCC valve kit 77754-04K (because vehicle has 182K miles on it)
GM replacement reaction shell, their upgraded one
GM forward sprag because brass top ring was scored and very very sketchy
I took it apart again this morning. fluid smells like skank ***, clutch material in the pan, along with some fine metal dust, but some larger pieces probably the size of those bullet points I used above.
fluid is red but smells burnt (I cleaned the case and VB with about 7 cans of brake cleaner, she clean)
clutch material in pan and small metal dust in fluid
I may have install the input drum bearing upside down (the one that goes over the sized numbered shim, mine was 71 i think)
new 2-4 band has score mark in middle of upper band, rev drums shows it, glazed and burn marks on it.
MOST of the metal was around the 1-2 accumulator, 3-4 accumulator and the 2-4 servo had a lot more metal than I thought it should have. I can follow the metal trace lines on the gasket of the bonded spacer plate.
2-4 servo seems out of wack, as in the part with the red or green oring on it, if pulled away just a 1/4" from the part with the pin that has snap ring (part with two teflon rings with scarf cuts on it) it has severe play in a axial effect, not spinning around, as if you were bending a pencil, it ***** crooked. the inside of that 'race' where smaller teflon ring goes. i see wear marks, but its not rough and I cannot remember if it was like that before or not. I dont remember playing with it too much before cleaning and putting new seals on with blue assemblee lube.
So... before I even took it apart I ordered a new corvette servo sandwich from www.GMtransmissionparts.com and a new rev drum. Also decided to get Sonnax pinless pistons for the accumulators and forward in VB. Im going to try and take apart the VB again and make sure I assembled it correctly, I went by using SI (Service Information) for GM techs (I work as parts counter guy at a GM dealer) I don't try to bother the trans techs too much at the shop, had to borrow a few tools like spring compressor and T50 Plus. But did it mostly on my own. Trans guy will be back in a few days, I pulled the unit on my own.
Just looking here to see if another may have insight. thanks for any and all help. I may be able to try a 2006 4WD VB from a used junkyard core or something we have laying around in the shop.
Mac
Thanks
Last edited by mntegra01; 12-18-2017 at 09:47 AM.
Reason: update
If I am reading right sounds like a pressure issue with the servo area, Are you saying the pin has a lot of play in the bore of the case, I have seen this the Sonnax replacement pin will solve that if the bore in case is worn you will have leakage from the 3rd clutch accumulator oil partially applying the band in 3rd via the pin to the 4th servo and or leak to case when in 4th gear.
Hope this helps some would have been good to get a PSI reading before removing trans when it was hot.
@performabuilt Thanks for a reply, I rechecked the VB to make sure everything was in right order, valves all move freely. 3-4 clutches are burnt, trans definitely overheated which was why I had no 4th when hot. I will pull codes on my lunch break. No CEL at the time but it may not always set a light from what mechanics here tell me. Also most of these guys a younger and its a remove and replace mostly with them, unless its obvious like a reaction shell or forward sprag.
I do think its in the one of the 2-3-4 circuit. But not sure WHY there is a bunch of metal in the filter and on the spacer plate. only taken trans down half way so far. lower half and output shaft all spins nice, but I am still going to take down and check. The WIT reman pump looks good inside. I did not compare to the old pump as far as internals go, but they are both PWM on the casting, and part number was U74500GA (i have the longer stator shaft) I took back out the Sonnax valve I had trans shop install and it looks right.
I'm really too far in to buy a GM reman, but as it sits, I still need some seals and 3-4 clutches, maybe steels and a new band. PLUS whatever has failed. I dont like the way the input drum-rev drum bearing feels. I'll dig more and report back.
I think it is a man-made problem because before the rebuild, the rev drum was in a lot better shape than after the 100 miles I put on the rebuild.
Checked for codes at lunch break. No codes with Tech 2. Tore it all the way down to the output shaft and low/rev piston. Did not find any scoring anywhere. Going to get another trans guy to look at it monday and swing by and chat with the local trans shop that did the Sonnax valve to get opinions from him. I am starting to think the new GM torque converter is bad, but the 2-4 servo pin looks a bit worn on the shaft, but there is little to no play in the pin bore. It is a 2 groove pin. The corvette servo assembly I got comes with a 2 groove servo pin, also the hard seals are not scarf cut, they are solid, so that should solve any leaking fluid in that area. I got pinless sonnax pistons for accumulators, that should eliminate leaks there.
On one side I hope its the TC, because I can't find any other scoring or wear from anything, I can recheck all the bushings again, I may have over looked something. If so that would be GM warranty and I can get service manager to work that out for me. If nothing else, I can get that covered and the seals, plates, drum, band I can buy again or see if they can cover those.
If its NOT the TC leaving metal gray stuff in the pan and sitting on top of the filter, then Im stumped and at a loss. It will be time to call Big Dave in I guess.
Ferrous. I decided to check it with a magnet before leaving work and I had shavings stick it. Fine metal dust. Im assuming its from a hard part: bearing, gears, or inside TC, but not sure what makes up a TC internals.
Im off work a few days, so Ill probably be in the shop putting trans back together with the new parts I have ordered. And give it a go. Getting real good at taking trans out now.
Ill be reading all about torque converters and such the next few days while off work. So.. I will definitely report back.
Looks as if I installed an accumulator valve upside down in the VB. The one with roll pin at the front and V neck around it. Both channels on valve body were blocked and the exhaust port in the cast side.
oops. Guess that could cause all sorts of weird issues.
Solved, I had put in the accumulator sleeve in upside down, blocking the ports in the valve body. The one near the shift solenoid B. I had everything else right. Been driving it around just fine now. The corvette servo in a trailblazer is kinda nice at WOT. Since I took it back apart, I put in pinless Sonnax pistons for all accumators (1-2, 3-4, and forward in VB), new or refreshed rev drum from www.GMtransmissionparts.com and also the $37 corvette servo from them. Reused original 3-4 steels, and put in new 3-4 fibers from WIT.
Parts warrantied a torque converter, reused the 2-4 band and new pan gasket and filter. good to go. Thanks for the excellent resources you guys have here. It was in another thread here that I noticed something different about my valve body. Then realized those ports were closed and I could see the aluminum sleeve all the way.
Thank you (!!) for the update.
And posting the solution even though you had to admit to assembling the VB wrong.
I think this is the 2nd/3rd thread where the OP installed the accumulator valve sleeve upside down. The next time someone complains about slow shifts after a rebuild, I will list the upside down accumulator sleeve as a possibility. Also, this part is removed when installing the Transgo HD2 shift kit, and IIRC someone installed it upside down while installing the kit.
Finally, glad you got it figured out. You certainly became a trans expert in the process.
Thank you (!!) for the update.
And posting the solution even though you had to admit to assembling the VB wrong.
I think this is the 2nd/3rd thread where the OP installed the accumulator valve sleeve upside down. The next time someone complains about slow shifts after a rebuild, I will list the upside down accumulator sleeve as a possibility. Also, this part is removed when installing the Transgo HD2 shift kit, and IIRC someone installed it upside down while installing the kit.
Finally, glad you got it figured out. You certainly became a trans expert in the process.
Thanks, I would be an *** and idiot for denying my mistakes and letting other people think that they can rebuild a trans without being detailed and through.
Here's where I recognized my mistake.
Originally Posted by clinebarger
Unless the Valve Body was modified, You cannot pull the Accumulator Bushing without dropping the Valve Body. This is the mod I'm talking about, You drill the roll pin hole trough the bottom of the Valve Body then use a Longer Pin. Trans-Go SK-4L60E kits come with the Pin & Drill Bit to do this.
I bought hundreds of them from a Auction that was selling out a Trans shop's inventory.
Look at the end of the Accumulator Valve Bushing, The "Horse-Shoe" should face UP with the Valve Body installed in the car. Attachment 632997
Then look at the bottom of the Valve Body where indicated, You should see JUST the Spool, Not a LAND. If you see a Land half exposed in the window....The Accumulator Valve is in backwards. Attachment 632998