Transmission light came on after Thermostat replacement
 

Hi guys,

I have read and searched just about everything relating to an e36 automatic transmission and I can't seem to find my problem. My engine was running cool and would never get to the proper operating temp so I decided to replace the thermostat using the pelican parts DIY article as a guide.

*NOTE* Before I tackled this job my transmission was shifting perfectly fine. My car has 115,000 miles on it.

Immediately after I completed the thermostat replacement the transmission light turned on and when I drove my car around the block it was shifting really harsh, especially when the automatic transmission down shifted. Also, my check engine light came and the fault code was the mass air flow sensor. Would this trigger the transmission light?? I am confused because my transmission was working perfectly fine before this simple job. I took my time and did the job exactly like the Pelican Parts article. What could I have done that would cause the transmission to start shifting so harshly?? Any help would be greatly appreciated because I have no idea where to start.

If anyone else is having this problem I will let you know how I fixed it...

long story short...i'm an idiot and didn't check all of the plugs and as I was looking around I noticed the mass air flow sensor was a little loose. I screwed in back in tight and my good 'ole 318ti is purring smoothly again.

Yup, if the MAF is disconnected it F's up the trans. Been there done that.