O2 sensors- bosch or gm
 

Tranny went down again and while it is out thinking of replacing the o2 sensors. The ones from GM are about $60 a piece and the Bosch are $32 each from Rock Auto. Any difference beside price? Going to do all four.

The truck has ~48K on it and ~40k blown. I'm not throwing any o2 codes but thought it might be good PM while the exhaust is out as I drive the truck like I stole it.

Get the gm ones. I went through 3 sets of the bosches then switched back to gm

GM! sparkplugs.com is where i got mine!!

GM.... i went through a set of bosch before i swapped back to gm.

another vote for the GM's...you'll likely spend more in the long run with the lower end O2 sensors

Dont waste your money. I have them come through the shop all of the time with triple the miles you have on those and still functioning perfectly. Leave them alone until you have a problem with them.

question:

Can one or more start going down, lowering power and gas mileage, without a code?

GM has 02 fail detection pretty damm sensitive. If the PCM see's a sensor not responding correctly they will set a code fairly quickly. If one is failing to the point of effecting gas mileage and or power you will have a MIL and code.

cool, thanks, just saved me some cash! :D

GM, but I wouldn't replace them just to replace them.