I have a 2000 blazer 4x4 and right now I no longer am engaging reverse, second, and forth gear. Not to mention when I try to engage 4-lo there is a loud bang noise.... I noticed trans fluid from the overflow tube... but as it stands I'm throwing a manufacturers trans control code of P1870 (slipping between 2-3 gear) and shift solinoid "B" fault... I believe I have to rebuild the trans but don't know how, and probably the transfer case but also don't know how... can anyone point me in the direction of free step by step instructions on one or the other or both.... don't have the money to pay a shop or I would.... any help would be wonderful... New member.... thanks alot..... this site is great....

 

The cheapest way to get it back on the road is to source a used tranny from a salvage yard. Just remember, it's used. If the t-case was not acting up before then I wouldn't mess with it until the tranny is addressed.

 

No reverse, 2nd, or 4th is a stripped reaction sun shell in the transmission. This is a hard part and the only fix is to replace it. The other codes should be addressed during a rebuild if that was the direction you were going in.

I agree that the cheapest approach is to get a used transmission, but it is not always the best approach.