http://www.gmt400.com/forum/ High performance and stock transmission questions and advice. en Fri, 10 Sep 2010 01:22:34 GMT vBulletin 60 http://www.gmt400.com/forum/images/Darkness3/misc/rss.png http://www.gmt400.com/forum/ http://www.gmt400.com/forum/showthread.php?1876-TCC-no-lock-up-after-driving-a-few-miles&goto=newpost Tue, 07 Sep 2010 23:03:47 GMT Newb Here!! Just like the title says, my 97 tahoe (350 vortec/ 4L60E) drives, shifts perfect when you first start driving it. The TCC kicks in at... Newb Here!! Just like the title says, my 97 tahoe (350 vortec/ 4L60E) drives, shifts perfect when you first start driving it. The TCC kicks in at 40mph on the dot and I can hop on the freeway and do 65-70+ no problem as long as im on the freeway with the TCC engaged. If I drive around town and do some stop and go for around 15-20 minutes and then hop on the freeway, I have no TCC lock-up what so ever. It does this about 90% of the time more often when its above 80* outside. When its hot I can almost count on it. Sometimes I can baby it into lock up by driving up to around 80mph at half throttle with no lock up and then let off the gas to the point where the throttle is just cracked open. after that it MIGHT slip into lock up. I haven't done anything to try and solve the problem yet because I dont want to just go into this without the slightest idea of what could be wrong. Any Help?? Ill buy drinks if we can get a sure fix to this (If your in the Cleveland area) this has been driving me NUTZ!! BTW after its starts to act crazy, 99% of the time its followed by crazy hard shifting 1-2, 2-3 and 3-4 but when its acting normal it shifts smooth as glass... WIERD?!?! ]]> Transmissions KingPin_Chevy86 http://www.gmt400.com/forum/showthread.php?1876-TCC-no-lock-up-after-driving-a-few-miles http://www.gmt400.com/forum/showthread.php?1858-4L80E-tranny-headache&goto=newpost Sun, 05 Sep 2010 00:49:19 GMT So... I traded two P.O.S.'s for a slightly polished turd. I knew when I bought it that it had a problem with the tranny but I was hoping it was just dirty. It is not that simple. I've spent the past two month (on and off) trying to get the tranny out of "limp" mode with no success.

Here's what I have:
'95 Chevy 2WD Dually with a 7.4L and a 4L80E tranny.

Here are my symptoms:
Will only shift between 2nd & 3rd but has reverse.

Problems revealed with an engine analyzer:
Bad MAP sensor - swapped.
Bad spark control module - swapped.
Bad Quad driver module
Bad ABS wheel sensor - checked and found section that feels like it was pinched (heading to the junkyard for a replacement).

Other work/testing I've done:
Could not find a downshift module for a 4L80E only a 4L60E. Changed the filter and shift solenoids. Checked for fluid on the tranny harness connector and it is leaking so the internal harness will need to be swapped, in the mean time I cleaned the connector with brake clean, blew it out with air and put dielectric grease in the contacts. Swapped the input speed and output speed sensors. I've checked the TPS and pulled the IAC and cleaned it (the code for the ABS is the same as the code for the IAC). Tightened all electrical connections to the bat. Swappped the ignition switch harness with a junkyard unit. Checked all fuses. Pulled an ECM from a junkyard van to test and this did not change the symptoms. Pulled out the meter and test light and started testing pins at the ECM and the tranny plug, I have bat & ign power to both.

My questions:
Will a faulty ABS sensor cable cause the tranny to go into "limp" mode?
When testing the pins with the ignition on I have 14.5 VDC on the 1-2 Sol. and 245 mVDC on the 2-3 Sol. does the ECM need to see certain perameters before it will allow the 2-3 to work? This is a ground switched unit.

I know I'm not listing some of the symptoms I've found but I can't think of anymore right now. I'm certain this issue is electrical but I'm not familiar enough with the system to know what steps to take next. I've been using the Haynes manual and the ATSG Tranny manual and have checked everything they have recommended.

Something else... this has a OBDI system in it. The only code I have found manually is on the ABS side. I had a local parts house hook a scanner up and it did not flash any codes. I took it to a local shop and they hooked up a Snap-on computer and found the codes for the sensors and modules.

Any help I can get would be greatly appreciated.

Thanks! ]]> Transmissions JimmyD55 http://www.gmt400.com/forum/showthread.php?1858-4L80E-tranny-headache http://www.gmt400.com/forum/showthread.php?1804-5-spd-manual-problem&goto=newpost Mon, 30 Aug 2010 20:28:04 GMT hello, buddy has a 91 z71 with a manual 5 speed the input shaft has play in it its loose so when it shuts off it shudders to a stop and it has... hello,

buddy has a 91 z71 with a manual 5 speed

the input shaft has play in it its loose so when it shuts off it shudders to a stop and it has a rough drive when shifting so we took it out.

im not even sure what this transmissions called..

we took it out and i split the case, but it would only come apart about an inch ]]> Transmissions trx88 http://www.gmt400.com/forum/showthread.php?1804-5-spd-manual-problem http://www.gmt400.com/forum/showthread.php?1803-Got-my-shift-kit-and-servo-finally-installed&goto=newpost Mon, 30 Aug 2010 13:46:24 GMT Ok i finally got my b&m shift plus installed and my tci 2nd gear servo installed and i love it. i didnt really believe some of yall at first cause when i first installed em it didnt really do much but bout the 2 or 3 day i could tell a BIG difference cause i have a 98 chevy ext cab 4x4 ALL STOCK with just exhaust with 33's and im catching second gear now its so awesome ]]> Transmissions 98chevy4x4 http://www.gmt400.com/forum/showthread.php?1803-Got-my-shift-kit-and-servo-finally-installed http://www.gmt400.com/forum/showthread.php?1795-Grinding-noise-engaging-reverse-with-5-spd..&goto=newpost Sat, 28 Aug 2010 22:41:57 GMT I went and drove a 98 z71 today with a manual trans and 104k miles, everytime i shiffted into reverse even from a dead stop, there was a loud clank... I went and drove a 98 z71 today with a manual trans and 104k miles, everytime i shiffted into reverse even from a dead stop, there was a loud clank when engaging, but only in R other gears were smooth effortless. is this a common problem or does it need a new clutch or trans? ]]> Transmissions mx450 http://www.gmt400.com/forum/showthread.php?1795-Grinding-noise-engaging-reverse-with-5-spd.. http://www.gmt400.com/forum/showthread.php?1738-Confusing-Problem&goto=newpost Fri, 20 Aug 2010 15:31:50 GMT Hopefully someone will have something to offer ... I think I'm going crazy. I have a '91 k2500 with 24,000 original miles on it. The issue I'm having is there is a vibration and a thrumming noise between the speeds of 30 and 50 mph. Here's the catch: It only does it when the ambient temperature is around 80 degrees or higher (the warmer it is outside the worse it is), or the truck is warm and the vibration instantly goes away as soon as you pull the 4x4 shift lever into 4 high. As soon as it goes back into 2wd, the vibration and thrumming comes right back, usually worse.
Maybe someone can steer me the right way ... my best theory I have going, (although I'm not extreamly knowledgable on the subject) ... it is my understanding that the 4x4 system on this model of truck is vacuum controlled ... so I am guessing there is a vacuum leak somewhere that is made worse by warmer temperatures that is causing the 4x4 to partially engage ... is this a possible theory, or am I way off base? I had someone ask me if I had had the recall work done in which the vacuum system was converted to electronic ... I didn't pay much attention to the guy at the time, he had a '94.
Thanks to anyone with any input,
~Cdawg ]]> Transmissions Cdawg http://www.gmt400.com/forum/showthread.php?1738-Confusing-Problem http://www.gmt400.com/forum/showthread.php?1723-Performance-vavle-body-on-4l60e&goto=newpost Wed, 18 Aug 2010 20:41:51 GMT Would it make a big difference if i put a performance vavle body on my stock 4l60e and whats some ways to make it run cooler Would it make a big difference if i put a performance vavle body on my stock 4l60e and whats some ways to make it run cooler ]]> Transmissions 98chevy4x4 http://www.gmt400.com/forum/showthread.php?1723-Performance-vavle-body-on-4l60e http://www.gmt400.com/forum/showthread.php?1673-Will-this-transmission-work&goto=newpost Fri, 13 Aug 2010 19:33:40 GMT My transmission in my 95 silverado 4x4 has been messing up, and i have a 1996 Corvette 4l60e and tci 3500 stall laying around. I was wondering if i... My transmission in my 95 silverado 4x4 has been messing up, and i have a 1996 Corvette 4l60e and tci 3500 stall laying around. I was wondering if i could make this vette trans work an what id have to do to make it work. There both 4l60e's an use the same clip.

thanks! ]]> Transmissions badassformula383lt1 http://www.gmt400.com/forum/showthread.php?1673-Will-this-transmission-work http://www.gmt400.com/forum/showthread.php?1661-turbo-350-in-an-88-4x4&goto=newpost Wed, 11 Aug 2010 16:19:08 GMT i have an 88 k1500 4x4. it has a 5 speed now, used to have a 7oor4 which went to the grave yard when the previous owner overheated tranny and blew... i have an 88 k1500 4x4. it has a 5 speed now, used to have a 7oor4 which went to the grave yard when the previous owner overheated tranny and blew the motor. so when i got it i dropped in a carbureted 350, and a 5 speed. this is a work truck/woods truck only. i was wanting to put a turbo 350 tranny in, but not sure if it can be done.
anybody got any ideas?
i would like an automatic since its easier to crawl through the woods than the 5 speed.
cutting or moving crossmembers or making new cross members is no problemif needed.
also, what transfer cases will work. i have the original automatic transfer case as well as the manual transfer case since the output shafts are different, along with both driveshafts. ]]> Transmissions FF1751 http://www.gmt400.com/forum/showthread.php?1661-turbo-350-in-an-88-4x4