Need OD advice!!!!
 

I may be purchasing a travel trailer VERY soon.
My tow vehicle is an '85 6.2 Suburban with 4 auto.
The possible hopeful trailer is a Holiday Rambler Aluma-lite, 32 ft.,
which reportedly only weighs 4,990#

My initial trip home would be on mostly VERY flat freeway.
Anticipate a 55mph cruise speed.
Safe to use the 4th gear OD until I sniff a real hill?
Is this trailer light enough not to hurt longivity of rear end?
My ratio is 3.73's.

If Suburban felt strong enough for this, at what border weight wise would
it be smarter to just keep in 3rd continuously???

Thank you for your thoughts!!!!

oops!!! Trailer weighed 3,000# more. Did the trip in 3rd. Still got better than expected
mpg. Didn't want to chance losing rear end or tranny...too much $ involved!!!