How did I miss this whole thread...
so from that quote 3.9 patrol will fit my rear but i need to get a R200A front diff and put the 4x2 3.9 gears into it ??? that sound right ?
Yeah.
The R180 was fitted as a rear diff to a bunch of cars so a C&P from one of them
might fit? Saves the changeover to the R200A.
now for me to be going 100 road speed i have to have 120 booked on the speedo! . its not healthy because thats about 3500 ish rpm and i have 265/70R16 tyres.
3500RPM at 100 is normal for a TD27 on 4.8s. Mine does the same and when I pulled my TD27 out, it had two hundred and something thousand on it, still going strong, and now the QD32 is at around 400,000 and happy, still doing the same thing. The sound of it at such high revs is unpleasant but it doesn't do damage.
also turns out its a petrol to diesel conversion could that have something to do with it? petrol diffs maybe?
More than likely the speedo gear in the transmission came with the engine/transmission combo, and came from a vehicle with a diff ratio of 4.6 or lower. You need a speedo gear to suit your diffs, which are 4.8, to make it read correctly.
whats the opinions on fixing it because i do high kays for work running between sites!!!!
Stress less, fit some sound deadening to the cab if it's loud, and if it really bothers you, fit some big-ass tyres (33") to make the ratio taller. It's a gutless motor and if you fit taller diff ratios, you won't be able to tow heavy things from a stop as easily, and have you tried it offroad with the 4.8s?? Weapon.