No overdrive
03-04-2012, 08:44 PM
#1
No overdrive
Looking for suggestions from experienced transmission builders.The truck shifts perfectly 1 to 2 to 3rd then lockup but no overdrive.Fluid looks good and smells good.Scanner shows no codes.I even unhooked battery for 1/2 hour but still same effect.Stock tranny 68xxx miles with servos and stall since 2004.I feel like it must be something like seperator plate or something cracked as nothing has been touched inside.I tried search but this does not seem like a common problem.It still shifts good at WOT chirps 2ND and shifts fast and firm into 3rd with no slippage.
03-06-2012, 06:31 AM
#4
Does your scan tool show the command for 4th gear and also the "A" solenoid being on? If not then your issue is not in the trans. As for the trans it might be possible that your 2-4 band might be starting to fail. Keep in mind in that bore on the side of the trans you have both servo's for 2nd and 4th gears. Both of which will have different effects on band clearance depending on how they were set up. What servo's are you using here? Also its possible that that the 3-4 shift valve might be hanging up some causing your issue here. I have seen this on a few occasions so its something to consider. Vince
03-06-2012, 10:16 AM
#5
Does your scan tool show the command for 4th gear and also the "A" solenoid being on? If not then your issue is not in the trans. As for the trans it might be possible that your 2-4 band might be starting to fail. Keep in mind in that bore on the side of the trans you have both servo's for 2nd and 4th gears. Both of which will have different effects on band clearance depending on how they were set up. What servo's are you using here? Also its possible that that the 3-4 shift valve might be hanging up some causing your issue here. I have seen this on a few occasions so its something to consider. Vince
03-06-2012, 01:06 PM
#6
What you're describing, is how mine acts when the 3-4 clutches and 2-4 band are worn out. While it feels like it isn't shifting into 4th gear, then lockup, it actually is. But it's slipping...
You'll need to get a scantool on there, like Vince described, to verify what's happening. But I'd bet that if you pull the pan, you'll see alot of friction material in the bottom.
You'll need to get a scantool on there, like Vince described, to verify what's happening. But I'd bet that if you pull the pan, you'll see alot of friction material in the bottom.
03-06-2012, 03:36 PM
#7
What you're describing, is how mine acts when the 3-4 clutches and 2-4 band are worn out. While it feels like it isn't shifting into 4th gear, then lockup, it actually is. But it's slipping...
You'll need to get a scantool on there, like Vince described, to verify what's happening. But I'd bet that if you pull the pan, you'll see alot of friction material in the bottom.
You'll need to get a scantool on there, like Vince described, to verify what's happening. But I'd bet that if you pull the pan, you'll see alot of friction material in the bottom.
Trying to figure out if its the band before I invest in shift kit,accumalators and seperator plate because I do not want to drop pan just to look and have to wait a week for parts to come in.Can not leave truck on jackstands in driveway as I live in high-fi resedential district.I have another trans when this 1 goes but would rather kill this 1st before installing.
Also did 3 runs Sunday from 0 to 110 mph testing out traction bars and never once bounced off rev limiter with shifts set at 6100 and 6000 rpms.
Last edited by WorkTruc; 03-06-2012 at 09:42 PM. Reason: add info
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03-06-2012, 09:23 PM
#8
same here...my trans performs flawlessly......once i get on the freeway and get above 60mph the rpms rise.....i can punch it and it will downshift just fine....but at freeway speeds the rpm's get up to 3000. around town it works fine no slipping and very firm shifts...i have a performabuilt level 3.
03-07-2012, 12:10 AM
#9
That's what I'm trying to tell both of you guys. Mine was EXACTLY like you are describing. On all three different times, the band, and 3-4 clutch pack was smoked.
Keep driving it. Watch your trans temps getting higher and higher when you're driving in what you believe to be 3rd gear. It's actually 4th gear slipping. I know this all too well.
Keep driving it. Watch your trans temps getting higher and higher when you're driving in what you believe to be 3rd gear. It's actually 4th gear slipping. I know this all too well.
03-07-2012, 06:38 AM
#10
Scan tool can only read codes and erase.As far as servos I have corvette servo for 2nd and Sonnax super hold for 4th.Is there a way I can check servos with pry bar pushing them into case and measure how far they move into case to tell if band is beyond limits?Thanks for reply.