Chevrolet 700r transmission

Hi, i have a 1991 chevrolet suburban, it has the 6.2 diesel with a 700 r4 transmission, at least i think that is what it is called.  I have had some troubles with the transmission and i heard that you could use different transmissions in it.  I don't know much about transmissions but i heard that there are stronger trannys that will fit.  Is there any truth to this and if so, what should i use?  I off road a little bit but most of my miles are highway miles.   

The 700r4 is one of the strongest tranny around . the overdrive is better for gas mpg. but you can use a th400 witch is stronger but only a 3 speed . you might have to change your driveline if the lengh of the trannys are different and make sure you get a 4x4 tranny becouse the tail shaft is different. if your 700r4 is not shifting properly have someone check the governor its a common problem

Thank you, like i said i have no idea and can only go from what i have heard from friends.  I am 330 miles from home so i just need to get it home and than i can have the guy that rebuilt it take a look at it.  I like the tranny when it is working but the 6.2 has got to go.  Do you have any suggestions for anything that i can do to it to give the diesel a little more power?  would a 350 be a stronger engine?  i have a friend that just rebuild a 350 and i was wondering if that would be a better deal?  

sorry i dont know much about diesels but i do know gm has others that are better than the 6.2 If I was you I would stay with a diesel just upgrade to a newer model  a diesel will have better low end torqe than a 350 plus more towing power and if you live in california like i do its easier to smog