I’m having problems with shifting when my 2000 blazer gets warm. While I first start driving around town my blazer starts and runs perfect, but when I get on the hwy and drive to work, I’m having shifting problems. When the blazer gets warm and goes below 65 mph, the blazer wants to jumping gears and starts jerking, as if it’s trying to find a better gear, and the speedometer starts jumping. If I go below 65 mph and try to speed up again, I have to shift manually or else the blazer will rev over 5K. As soon as I pass 65 mph the blazer will work fine and the speedometer will start working normal again. When I slow down, using my brakes, the ABS light will turn on. I have the following error codes: 0118, 0740, 0753, 0758 and 1860.
I’ve been reading the forum for help with fixing my problem. I’ve changed out the three solenoids, the two (shift) at the front of the transmission pan and the converter (TCC) solenoid at the rear passenger side of the pan. I had a friend take a look at the problem and when he drove the blazer, after the car was warm, and he had no problems at all. I thought it was the ignition switch, so I also changed it out the from a dealer part. I’m at a lost and would appreciate any help.

 

whats your fluid look like? also mine was doin that and i added lucas transmission fix and it took care of the problem it takes a while to put in and you have to have your vehicle running while you put it in through the dipstick kneck but try that and see what kind of result you get it decreases transmission heat and so mine after performes so much better it shifts like brand new no problems and ive had the lucas in it since december almost a year now i use all of lucas's stuff oil additive tranni fix fuel treatment its all good stuff i would use there oil if it wasn't 7 bucks a quart but i will try it on my next oil change i believe in that stuff alot cause it works. any other questions just ask

 

The 'fix-in-a-bottle' type solutions should be used after some more conventional things have been tried. I have used the Lucas Trans-fix before in my old '97 Ram that had a check valve stuck open that was resulting in the torque converter emptying itself when the truck would sit for prolonged periods of time. The lucas stuff freed up the check valve.

Your present codes:
P0118 - Engine Coolant Temperature [ECT] Sensor Circuit High Voltage
P0740 - Torque Converter Clutch Circuit
P0753 - Shift Solenoid A Electrical
P0758 - Shift Solenoid B Electrical
P1860 - TCC PWM Solenoid Circuit

With all of the transmission codes, I would disconnect the electrical connection on the side of the transmission and make sure that it is clean and all of the pins are going to the appropriate place. I would then recommend inspecting the wiring harness from the PCM to the transmission for signs of wear. This sounds like more of a wiring problem than anything in the transmission, but if left unchecked, it could ruin the transmission.

 

I've checked the electrical connection and cleaned it with elettrical spray. The pins looked clean and straight. I've also checked and cleaned the connection for the speedometer. I've tryied to check the wires that come into the transmission, but they go on top of the tranmission areare difficult to check. I've tried to follow the wires from where they start, but could not find the exact spot where they start. Any tips on how to check these wires?

 

they go up and over the tranni huh i would trace to see if there is any hold downs that hold it up and acroos if there is disconnect them and see if you can move them to inspect if not you might have to drop the tranni down if you have to do that i would start with the tranni mount and see if by taking that off if that will drop it enough to look at the wiring

 

I took my truck to a buddies shop and had it put on the lift to inspect the wires. I found no wear on wires leading from the transmission. I still feel that the problem is electrical. I’m wondering if it’s a speedometer problem. After about 20 miles of drive time is when my transmission begins have shifting problems. When this problem occurs, the only other indicators is that the ABS light turns on and the Speedometer starts dancing back and forth. When I get below 30 mph, the speedometer drops to zero and will not move until I go over the 30mph. And then it will bounce around again. It will also stop bouncing when I get over 85mph and will function correctly until I go below the 85mph. All other gauges are working fine. Does the transmission shifting problem make the speedometer go crazy, or does the speedometer make the transmission have these sift problems? Or might the electrical problem be with the ABS system because this is the only indicator light that is lit on the dash?

 

TPS???.