| if its an 01 525i in the USA then it has traction control. It absolutely can be affecting the transmission. The ABS module is connected to the engine and transmission modules by the CAN bus. If the module is shorting out it can pull the can bus down and create problems with the engine and the transmission electronics. it can put the transmission in to failsafe and you will only have 3rd gear. The price does seem a bit high tho. you may want to shop around a little. i think you should be able to get it done for under $1500.
where are you located? | 
