Thanks for the replies so far. Based on the volume it looks like this is an issue that not only I might have had questions about. :)
I will try and answer / clarify issues raised in the foregoing replies.
1. It is a 2WD truck so only the rear end needs to be changed.
2. The quote that I got from the dealer was $2400 for parts and labour whereas the quote I got from 4Wheel Parts was less than half that for parts and labour. I did not seek any other quotes so far.
3. I have a programmer that can account for different axle ratios and wheel sizes among other things.
4. Emptypockets - what do you mean by the truck was "not up to doing the job" after your upgrade?
5. I want to balance towing with daily driver duty hence I only want to go to 3.42. Anything higher I would get a different truck since 1/2 ton trucks are payload limited anyway.
6. retispcii - we travel light and have no other people other than DW and me. I expect that we will continue to travel light as I don't like bringing a lot of junk with me. That said, with the greater CCC I may bring my bikes. Everything else stays the same as I bring in the RV in my sig.
7. APT - There are second-hand trucks that I could swap with but the difference in expense would not be about $1200. Besides, my truck was bought new and works perfectly. Buying second hand means buying a pig in a poke and I am not really interested in other issues. Thanks for the tip about the 3.42 fitting in the same housing as the 3.08. The G2 gears from 4 Wheel Parts also fit. A noted before I do have a Hypertech tuner already - works great.
8. the bear II - I would bet dollars to doughnuts that the Sierra with the 3.42 rear end has exactly the same parts as my truck. I do note however that it seems that those trucks have rear discs and mine has rear drums. My truck came with the same trailer package so it has the Z85 HD trailering, HD cooling, HD wiring and also has "high performance suspension" (not HD suspension). I would have no issues adding an AM (engine) oil cooler as well - I was thinking of doing that anyway.
9. carringb - I have not had any issues with my tuned truck at the dealer, and my tuner has the ability to return to stock tune if need be.
10. Ram4sam - I was intending to not do this upgrade until the trailer was purchased AND it is not pulling to my satisfaction. We went to the dealer today and DW decided she does not like the colour scheme on the fabric and the slideout fascia (I had no issues with that at all), and she did not like the trade in value they offered (which I agree with). She did not want to commit today anyway, so this is not a done deal.
11. adayjk - Not sure I understand your point. No one is wanting to tow beyond the limits. I want to raise the limits so I have a bigger buffer for a stronger pull. My programmer can change shift points although I prefer not to mess with that.
12. lbrjet - Could you please elaborate on "more coolers" on the 9500# truck versus my truck? Do you have specific knowledge on this? Just wanting to know whether this is opinion or fact. As mentioned before I do have the HD cooling package.
So far the consensus seems to be, yes it will make a difference in the tow ability of the truck. Whether or not the capability (not rating) would be raised to 9500# is still in question. (I put rating in parentheses because only the manufacturer can issue a rating).
For me as long as it pulls this 7500# RV over reasonabe slopes without speed falling off terribly and without the tranny overheating or anything like that then I am happy. I would love to get a diesel with lots of payload and torque but cannot swing that with the new trailer.
Looking forward to your follow-up replies. I will be monitoring closely for any additional queries / clarifications. Thanks again to all for the responses so far.
