Duramax tranny problem

[lbzdmax01]

Hi all! I am new to this site so I apologize if this is posted in the wrong section. I have an 07 LBZ duramax and just drove 3000 miles towing 4500 lbs. I know this is not a significant amount of weight, but I thought that might be useful knowledge for the problem I am having. About 4000 miles ago when shifting from drive to reverse, or reverse to drive, I began getting a pretty hard gear engagement. my driveline seems tight. On my road trip at one point I lost tranny temp and the light that illuminates "drive" went out. I had "tow/haul" engaged, and had an indicator light, but it did not seems to actually be running in tow mode as the tranny wouldn't downshift when i was braking, and my shifts were not as hard as they should have been. I shut the truck down and restarted it and same thing. I restarted it again and everything was normal and I have put about 1500 miles on it and not had the problem reoccur. I will say that on my trip my trans temp was all over the place, but never over 205 (150-205). I stopped in Reno, NV and went to taho with out the trailer and my temp was around 205 with outside temps around 80. Do I have a serious problem brewing? my biggest concern is the slamming into gear. I have noticed that if i shift to N and pause a second before going into a gear it happens significantly less. Any help is appreciated!

 

I should add that I have 158k on the truck, and do not get any codes with these problems.

[newdude]

I'd check fluid level. With the PRNDL dropping out, the neutral safety back up switch (NSBU) are known for issues, although mainly the older Allison 1000. The pressure and temp issue could be from the transmission pressure control plate in the pan which also has the fluid temp sensor as part of it.