I had the same problem on my 1999 Pontiac GA 3.4 litre. Replaced a bunch of stuff. It just kept pushing the coolant out the overflow once the temp got to 200 + like to drove me nuts. Ended up being that reservoir. If you measure the O.D. of the cap(brand new cap) and the I.D. of the reservoir filler neck there is no way it will seal(even tried to fit a different type cap,no luck). The system has to be able to build pressure or the coolant will boil out at 212. Causing the coolant to be pushed out the reservoir. Why? you say or How? did the filler neck increase in size. I dont know but GM has write ups about this problem. They say sand it with a piece of sandpaper to smooth it. Maybe someone sanded it way to much?? Around $40 bucks and I was on my way. Hope this helps someone.
You will have to retrieve the engine faulty code with a scanner to see.
Explaining in some case when the PCM (Powertrain Control Module) sense a problem for some code it will deactivate the TRACTION system for security.
I believe there is a faulty code after the code is solved then erase all codes and try again. The TRACTION light should be back on.
Without testing hard to say . Do you know anything about automotive electrical systems , OBD 2 engine management system ? IAC - idle air control ? What engine sensor data is ? Hooking up a professional type scanner , reading DTC'S etc.... How to test electrical circuits using a DVOM - digital volt ohm meter ? 007 Idle Speed Problems Scan Data for Idle
replaced front and back brakes already ??? This has nothing to do with the ABS ,traction control is part of the anti-lock brake system . Light's on DTC'S - diagnostic trouble codes stored in the ABS control module . Sorry but , your best bet ,take your vehicle to a qualified repair shop , before you hurt yourself. Take's year's to learn how to diagnose these electronic control systems
Before listening to someone telling you to replace plugs & wires an filter an injector cleaner etc. An when that doesn't fix the problem they say the MAF sensor or coolant temp sensor ,throttle position sensor . Spend a 100 bucks for diagnostics an then know for sure whats wrong . So many sensors an electronic's on you vehicle . See this guy above isn't a tech . back yard shade tree probably . He is all ready telling change the filter an if that doesn't work change the plug's an wires an this an that .
Have scan data checked first ,before replacing any parts . I have thirty years experience , Dealer ship , independent repair shop , own shop , mobile diagnostic tech . I charge $24.50 to hook up scan tool ,factory scan tool , an view engine sensor data . Could most likely be a bad or dirty mass air flow sensor . O2 sensor .
Check the transmission fluid level. Also check the rear differential if your car has one ( I think the 99's were still rear wheel drive) for fluid. If either of these are low, the fact that things are fine indicates that the low fluid level is causing problems. Also, the trans fluid should be a nice pink color. If it isn't then the transmission is not in good shape and should be looked at again by the rebuilder. If the fluid levels are fine, have the rebuilder check the trans again to see if he missed something.
The issue with the temp gauge is entirely separate except if you mean that the car begins to heat up when the shifting problems are occurring. If the temp gauge goes way up then comes down quickly regardless of how the car is being driven, the thermostat may be sticking and should be replaced. If the car is hard to drive and then starts overheating, the transmission may well be defective and causing the engine to work harder than it should.
The Trac off and abs lights being on together are a related problem. With your check engine light on shop should be able to tell what is wrong. Go to AutoZone or similar and have them scanned the computer for codes then get a new shop