air condition in a gmc jimmy?
- Thread starter Eileen B
- Start date
Molson02536
New member
Your A/C should not have to do anything with your transmission slipping. You can try replacing your TPS which could be giving the PCM bad signals.
Secondly, put a line pressure gauge ($55 at Auto parts store, or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.490" boost valve (easy fix in pan).
Soft shifting, gradual performance degradation means Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R. Also try a transmission flush with BG brand products.
Keep us posted and more transmission shop will test drive your Jimmy to test your transmission with a tech2 scanner.
i have this exact same issue as well. there has to be a correlation. it ONLY happens when i run the a/c. when i step on the gas, the rpms go up, the engine roars really loudly, & moves very slowly. the transmission was just replaced about 1000miles ago. it had this problem b4 the new tranny, and after the new one, still has it now. the only thing i can think of that might connect them is that my blower motor resistor is probably fried. my a/c and heat only works on high setting. anyone have any ideas?
Vacdaddyt
New member
A/C
Like the other reply A/C should not physically affect the transmission unless its clutch is pulling too many amps lowering the voltage supplied to the transmission. If there is a tie in it would be from the computer not sending the correct info but I do not think this likely. Try unplugging the A/C compressor electrical cord and test it to see if it still does it. There is a small connector by the pulley of the compressor, unplug it when the motor is off and tie it so it will not get tangled in the pulley and test drive it to see if it goes away. I know the computer is to change settings when the A/C is turned on as far as idle and some of the shifting but can't help you beyond that.
Like the other reply A/C should not physically affect the transmission unless its clutch is pulling too many amps lowering the voltage supplied to the transmission. If there is a tie in it would be from the computer not sending the correct info but I do not think this likely. Try unplugging the A/C compressor electrical cord and test it to see if it still does it. There is a small connector by the pulley of the compressor, unplug it when the motor is off and tie it so it will not get tangled in the pulley and test drive it to see if it goes away. I know the computer is to change settings when the A/C is turned on as far as idle and some of the shifting but can't help you beyond that.
Vacdaddyt
New member
A/C
Try unplugging the A/C compressor electrical lead and see if it changes. It is located by the pulley, With motor off, just unplug the connector and tie out of the way and test it to see if it does the same thing, and then re-plug it back in. The PCM/ECM does control shifting and idle speeds when the A/C is on but it is not likely the problem. I don't know how to test them for that.
Try unplugging the A/C compressor electrical lead and see if it changes. It is located by the pulley, With motor off, just unplug the connector and tie out of the way and test it to see if it does the same thing, and then re-plug it back in. The PCM/ECM does control shifting and idle speeds when the A/C is on but it is not likely the problem. I don't know how to test them for that.