New trasmission and pulling

You have a real problem on your hands. Not only did coolant get into the transmission, transmission fluid most likely got into your coolant as well. The trans fluid will eat the lining of all the rubber cooling hoses and cause them to soften and eventually fail, and will cause a black, gunky color in the coolant. You will need to:
1. Replace the radiator since the trans cooler inside has broken.
2. Replace all coolant hoses and flush the entire cooling system.
3. Have the transmission rebuilt or replaced to ensure all coolant traces have been removed.

There is no easy fix for this....I had to do it myself.

pull the transmission oil pan. its right underneath the trasmission. its a pan with atleast 12 bolts if irember well

if its stay in second speed the computer put the tramission in limp mode because there a problem in the trasmission you need to get your van pass on a scanner to see the code it could simply be the input or output sensor there sensor on the transmission and to reset that simply disconnect the battery for 2 minute after you see your trams will change all speed let me no and thanks for using fixya

when u installed transmission, did u also get torque converter with the transmission you purchased.
most times torque converter has to be matched especially with a used transmission.also need to make sure torque converter filled properly with fluid when you installed new transmission

No, O2 Sensor would make your van to be none fuel efficient at least or won't change anything if it's the O2 Sensor or Bank2 ( It mean's the 2nd one, the 2nd one is a dummy.. it just read what's going out from the catalytic converter and tell's the computer if there's a change since the reading of the first 02, so the computer see if or not the catalytic do his job ) For your Jerking and Jumping problem.. those Gm Van has alot of transmission problem and maybe your transmission on a way to take vacancy or it is just missing oil ! Check Oil first, for that do that when the Motor is Cold, Start you Van Leave it in "Park" Position, Pull the Dipstick of your transmission ( Should be the Red one ) clean the end of it with a Rag and put it back, pull it a gain and check if the oil is in the reading, if not add the missing oil while the motor turn's, and recheck it until it's full ! Otherwise if the dipstick show's Full, Here's a tip's go to your local autopart's supplier or store that sell's car product such oil's, coolant ect.. ! Buy a Bottle of : Lucas Transmission Fix, Remove the Transmission Plug, and remove about the half of the oil ( Not the Whole amount of oil, only the half it's important ! ) and put the plug back well tighten, pull the dipstick and add oil from the dipstick tube with your bottle add about the half of the bottle, start your van, check the oil level if it still missing some oil add the amount it require to be full ( While Motor is Turning ) ! Important do not Overfull the transmission ! This Should Work or not, if not.. I would say you need to Replace your Transmission, What I told you is about 15minutes of your time and a couple of dollar ! Best thing is to bring your van to a Transmission Shop they will tell you the problem !

what are your symptoms? I havea 2000 and have had all sorts of tranny probs that have been fixed by servicing it - not just flushed, but filter change too. Additives like trans-x or lucas oil transmission cleaner or conditioner can help fix problems too, but only temporarily. Oddly enough, the best deal in town was the GM/ Caddy dealership for filter change and full flush of transmission (with cleaners).

Mine runs like new now after not downshifting when accellerating or shifting into 4th gear. These vans cook their fluids quickly because everything is packed in so tight!

Depending on the location of the leak from under the van. With the van setting on level ground have someone to fill the transmission with fluid( do not overfill) look under van to see if the fluid is coming from the front or rear or middle of transmission. If you cannot look under the van then use a large piece of cardboard and slide it under the van before you try to fill it to locate the leak. leak could be front or rear seals leaking or the pan gasket leaking. hope this will help you.

if you only removed the transmission pan you should only need about 6 quarts. the transmission dipstick has level marks at the bottom of stick keep the amount in between the marks.

When was the last time you changed the trasmission fluid in your van if it has never been done do it and the filter aswell, before you change the trasmission.

You can get the Tranny Rebuilt for a Couple of Hundred Compared to a Few Thousand. I would rebuild it. Please Rate My Response! Thanks!