hello , I have real mijor problem with my "Jeep Grand Cherokee 1999" Auto-Trinsmison system  My Jeep problem in brief : after I drive it for long distance like 100Km or above, the overdrive will turn off by itself and that will make my Gear Temp goes high and then it will damage the whole transmission system. I even replaced the Gear itself twice but I still have the same issue if you have a solutions for my problem hope you reply for me or even ant tip or advice will do ! My buddy's want me to sell my Jeep but I know there is a solustion for my problem !

I don't know this for sure, as my experience with tranny's is quite limited... but I wonder about the temp and the miles you have to drive before it happens.  If I remember correctly, I thought I read somewhere about shutting off the O/D when you're putting a lot of strain on the tranny (such as climbing hills and towing) to keep it from overheating.  I'm wondering if your transmission is getting hot enough on it's own that maybe the system is kicking itself out of O/D automatically?

Have you checked the fluid and especially the transmission filter?  A low fluid level or clogged filter could lead to heat build up.  Also, does your jeep have a transmission cooler?  If so, maybe there is something going on there that is not allowing it to perform as it should.

I would have to say it sounds like a computer issue. I have a 93 grand and when my computer went out, it messed with all sorts of stuff. I would say take it to a dealer or shop and have them trouble code the computer and see if any thing comes up. Also check the releys and fuses connected to the tranny, maybe some thing has come lose... Good luck  

ya change the filter etc, and if you donot have one get a tranny cooler...should fix it.