95 blazer 4l60E trans problems! help!
 

i have a 1995 chevy blazer 4.3l with the 4l60e. i am having a few problems with the transmision and im wondering if you could point me in the right direction or tell me how to fix it. heres a little info on the trans, the only thing i have done to it is a b&m shift kit. so the problem is that when i am at a dead stop like a stop light, and i punch the gas, the trans will start off in first gear but almost imediately upshift to second? is there anything that i could have done wrong with the shift kit to cause this? it will only do it when i am hard on the throttle off the line. if i am easy on the throttle from a dead stop it shifts normaly. also another problem i am having is that it seems when the transmission gets hot/running temp it will kick out of overdrive when im going down the highway. so i am stuck going down the highway at 65mph with the engine reving about 3000rpm. i have to stop, shut the truck off let it sit a min and restart it, then it will go into overdrive but will kick back out of overdrive in a few minutes. it does not do this when the transmission is cold or not up to full running temp tho. any help is very appreciated! oh and i did talk to a transmission mechanic and he was unsure of wat could be wrong, he said with the shift kit changing the pressures in the trans it could be messing up the trans computer.??

thanks
nick

bump, realy need some help!

bump! help please

First question... Did it do this before the shift kit install? If the answer is no, then there is a VERY good chance that you did something incorrect during the installation of the B&M shift kit.

If this was the older 700R4, I'd say you have a problem with the governor or possibly a TV cable adjustment problem, but neither of those exist in the 4L60E that you have.

The loss of OD when hot is interesting and the two symptoms together could mean that something is shorting out in the transmission harness inside the pan, causing the ECU/PCM to go to a 'limp-in' state engaging only 2nd & 3rd.

It is highly unlikely that the shift kit "messed up the trans computer".

it did not do this before the shift kit. :icon_doh: should i pull the valvebody back out and check everything over? what should i check for? or is there any other explanation?

so i did some research, found out the tps sensor could be bad, so i tested it with a multimeter. it tested good, ohms climbed and decreased very smoothly. so then i checked the trans fluid level when it was hot, it was about a quart overfilled. i syphoned it out till it was right in the hashes and at a good level now. i work at a shop, so i used our snapon verus scanner and scanned for any engine or trans codes, i came up with a p1122 code. (tp sensor intermittent voltage, i think) i cleared the code. i heard that a code could cause the trans to go into a limp mode or somthing? then i checked the vacume line and wiring going to the 4x4 engageing solenoid on the front t case for any cracks or bad wiring, all looked good (i heard a bad vacume hose could be causing my problem also, cause the pcm thinks the 4x4 is engaged?). so after all that i took the truck out for a test beat. still did the same thing it did before....:icon_hyper:. when i would come to a complete stop and pin it all the way to the floor the trans would start in 1st gear for a fraction of a second then it would imediatly shift into second.. but if i came to a complete stop and took off normal on the throttle it would shift normal. i also took it down the highway to see if it would still come out of overdrive, but it never came out of od, not to say it wont do it again tho. but maybe one of the things i checked or fixed could have fixed the over drive problem? well im stumped... my next thing im gonna try, if no one else has any ideas, is take the valvebody back out of the trans and inspect everything and replace the 1-2 solenoid, 3-4 solenoid, 3-2 downshift solenoid, and the boost valve. also maybe the epc solenoid and lock up solenoid (good idea? or shouldnt they have to be replaced?). thanks for any and all help guys!

nick

You should test & inspect the solenoids before replacing them. Inspect the nose of the solenoid for cracks and test the resistance of the solenoids to spec (can't remember off the top of my head).

And just a little advice. Your posts are quite difficult to read. The combination of run-on sentence structure and use of capitalization makes it all jumble together. The easier a post is to read, the more people will get through it and offer up their opinions.

okay, yahi will test the solenoids. and sorry bout my grammar... but is there any thing else i should replace or check for? any hints on what my problem could be? also since i most likely will be digging back into the transmission pan and valvebody, is there and performance upgrades i can do?

thanks
nick

bump, anyone?

any ideas on whats wrong? :icon_shrug: