towing with 2000 manual jackaroo se turbo diesel

5th gear is a weak link in most vehicles and yes things probably would last longer in 4th but seeing as most of us live in the real world probably best to change back to 4th sooner rather than later when using the tourque of the vehicle eg hills and overtaking otherwise cruise in 5th

as 5th is on a lay shaft it can be used with light loads no worries , but heavy loads use 4th, anyway how fast do you want top pull a couple of ton. Applies for all vehicles with conventional boxes.

Yeah, just run 5th on the flats, change back to 4th BEFORE you start going up the big hills, don't wait for it to struggle. Then you'll have no probs!

G'day Grant
I bought a 96 Jack, and the bloke who owned it before me had horses and he towed everyhting in 5th. As a consequence, I had to replace the bearings in the box and transfer case and it wasn't cheap. It cost me a week off the road and $2800, so I would recomend you only use 5th on very flat roads and NEVER on any incline at all.
Cheers
Andrew

Isn't there a set top speed you are allowed to tow a caravan at?

My 99 version of the vehicle you describe is still ok after 5 years - towing camper trailers on bush trips, using 5th where applicable - as others have said, we simply need to "feel" the load as we drive and use 5th only to maintain a cruise situation - no real work.

Hi Grant I agree with Banjo, I have a 99 TD Jack and as with most 5 speed manuals you have to "feel' the motor and torque . As a rule of thumb I never change upto 5th gear until I reach 80 Ks and back down the same . As for the "feel" if you are an astute person you will notice a small harmonic in the motor under light load at about 1800 RPM or 75Ks in 5th , this harmonic can be the cause of wear in the transmission generally.And before all the anti Jack people say I told you so you will find all motors have this somwhere in their rev range , particularly diesels. In summary don't load it up in 5th.

Cheers Dave L