4X4 question

[RTStork]

My dad has a 4x4 4-runner and when he pulls his 16ft trailer he puts it in 4 high but doesn't lock the hubs. It seems to gear the transmission down and it pulls the trailer much easier. Will this hurt anything? and explain how it gears the transmission down without locking the hubs in? I don't know anything about 4 wheel drives so i hope this doesn't sound like lame questions.

 

[offroader_69_me]

well I am not sure how it affects the gearing I believe (and could be wrong) that 4 high does not change gearing on a stock t-case only splits the power to front and rear 4-lo does of course but it also tops out around 35 I am not sure of the ill-affects if any but I dont think it is real good on anything. just my 2 cents