I just bought my son a used Blazer and it seems like the transmission is acting up. It is real sluggish from a stop. Seems as if the trans is in 4th gear. If I manually shift down I have more torque from a standstill and manually shifting up in gears seems to work. Where do I start troubleshooting?

Thanks in advance,
Carl

 

1. Change Transmission Fluid, Check The pan and Fluid for Metalic flakes and particles, Most have a magnet in bottom of pan to collect those a lot of it can look like glitter. This will tell you if gears are being worn away and going out
This will also relieve a clogged filter and restore torque and fluid flow to converter-gears- and cooling system

2. Check Vacuum Lines and plugs going to the transmission, check vacuum Lines period. Shifting works off vacuum as you get more speed you have more vacuum so in the lower gears initially it will take a while to shift a really good starting point.

Question:
do you have to let off gas to get it to shift right if you dont start in lower gear and work your way up?

 

its probably starting in second gear. check your ign/gau fuse for the heck of it see if thats blown. i had the same issue and its something to do with my computer not sending grounds to the solenoids when needed. i fixed that problem now ocasionally my ign/gau fuse will blow again giving me a second gear start.