99 chevy blazer transmission pumps work on it but will not engage into any gear

check for a faulty starter relay
pull the starter and check for burred teeth on the ring gear
have an auto electrician check the solenoid for burnt points sticking together
also check the over run clutch operation on the pinion as if it is not operational the ring gear will keep the pinion engaged

No that doesn't sound crazy at all . Given the electronics on vehicles today . What year is your blazer ? For the transmission to shift or engage gears the PCM/TCM which ever controls the trans in your blazer ,inputs from various sensors are needed. One being the TPS - throttle position sensor . Stepping on the gas pedal changes voltage signals to the PCM - engine computer . If you hooked up a volt meter on the signal wire to the PCM from the TPS at idle you would see around one volt an gas pedal on the floor around 4 1/2 - 5 volts . Check the connectors at the transmission an the PCM for being tight . Having a scan tool that reads sensor data hooked up to look at sensor parameters could be a big help .

Even if all the electronics were dead you still should have movement in some gear, usually reverse and 2nd. If you put the transmission in park [and have both back tires off of the ground a bit] can you turn the rear driveshaft by hand? If so then the transfer case isn't connecting the driveshaft to the transmission. If the driveshaft won't turn then you know it''s connected internally and can look elsewhere. Only other thing I can think of is possibly the front pump in this 4L60E may be damaged and not capable of pumping any oil. You could disconnect one of the cooler lines and see if it pumps any oil out with the engine running. No oil means no pump action. Hope this helps a bit and good luck!

Just a seal removal tool or a screw driver, pops right out.

You may have vapour lock in your heater lines. Start engine, put heat lever on high, disconnect one of the lines on your heater core, the one on the flow out side, & see if you have any air coming out. Once antifreese comes out stick line back on & retighten clamp. Make sure your cooling system is topped off. Also your water pump may not be functionihg to it's maximum. Take rad cap off cold & view flow rate. If inadequate you may have to replace the water pump. Good luck!

Your going to have to take to a transmission shop and have the blazer scanned for the problem, You could have a broken sun gear which is common or I have also personally seen/fixed a 99 4L60E that had a broken reverse servo piston,it is the piece that engages the low/reverse band under a cover in the valve body area,a piston with a band engagement pin. Anyone that has this problem can have it repaired in the vehicle,its worth checking BEFORE replacing the trans unless the fluid is burn't or there are other symptoms present.  Good luck and hope this helps. keep me posted, be glad to help.

its the actuator on the front diff . this is a common problem and a easy but expensive fix

Personally, I would return it to the dealer and state that is still not fixed.
When the remote start / security system was removed or disconnected, the starter circuit would have had to be rewired as the remote start / security system prevents the starter from engaging.
The wire splicing that would have had to take place may still be a problem.
If you would rather diagnose this problem your self I will be happy to help.
Let me know.
Regards,.

I would take it back to the person that rebuilt it and make them fix it again or get your money back if you can

Well it sounds like you have a the vacum for the four weel drive is trying to engage when it is in nutrial and that is where the noise is comeing from. I just think the person you took it to is just trying to make some money off of you