I purchased a 88 Wrangler Laredo, never had one, guy used it for trail riding and some mudding. It seems to be geared low, 2100RPM @ 55 MPH and 8 MPG. I would like to gear it for highway and some beach driving use. I know that both axles have DANA stamped on them. The front has a date of 1985 and the rear is dated 1987. Whats your advise? Thanks!