4L60E won't shift into reverse correctly

thecraft · October 7, 2006

Alright, I've got two problems with my '95 that I hope someone here can help me with.

The first problem is that my transmission (4L60E) has trouble shifting into reverse. It rarely shifts into to reverse properly, maybe 10% of the time at the most. Most of the time it will engage, but the truck rattles like crazy and moves very slowly. Sometimes if I rev the engine a bit while it's doing this, it will engage with a soft lurch. The rest of the time, the truck will just sit there. If I rev the engine, the transmission will engage with a violent jerk... I left a couple of tire marks in parking lots doing this. It's been doing this for a while now (since the previous owner had it) and seems to be getting slowly worse. The only temporary fix I found is to shift back and forth between Park & Reverse until it works. The transmission works perfect other than that...

The second problem isn't serious, but I like to get rid of that d**n SES light. I used the ol' paper clip trick to retrieve the service codes and turned up with "32 - EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal." I know that service codes aren't always accurate, but I'm willing to bet that it's my EGR valve because it's never been taken off since the truck was built. However, I don't have any of the symptoms of EGR problems like rough idle (valve open) and engine knock (valve closed). Anyways, if I take off my EGR valve, how can I check if it is working correctly? Can I clean it with something like carburetor cleaner or do you think I would need to replace the valve?

Thanks for your help!