Gearing issues

Bought a 2003 TD5 Disco2 and have always thought that the engine is running a high revs at speed.

Ifindin 5th gear the revs are a little high but I don't know what's normal as my other Disco is an Auto and has been fitted with a bigger TC that locks at about 2000 rpm so I get good mpg and it was remapped to suit the box.

What rpm should I see at the speeds below in a manual 2003 Disco, my Tyres = 255/65/16.

These are the reading I have but I'm sure either the R380, transfer box or diffs are wrong.

40mph = 1770rpm
50mph = 2220rpm
60mph = 2680rpm
70mph = 3150rpm

I thought that at 70mph I should be doing about 2700 rpm.

If you think you know what might be wrong, please let me know as in Aug I plan to drive to the Uk and over the two weeks plan on doing 2000+ miles.

Just been to the Ashcrofts website and mused the ratio calculator and it looks like I might have 4.11 diffs fitted, how can I tell what diffs are fitted in my Disco?

if you jack up one wheel mark prop and diff housing and mark wheel ,for one rotation of wheel prop will turn 1 3/4 with 3.5 and twice with 4.1

Prop turns 1 3/4 for 1 rev of the wheel, so it's not the diffs.

Where on the transfer box will I find a number to tell me what it is, my thoughts are it might be one off a D1 cos on the Ashcrofts calc if I select D1 (34D) it show the same rpm/mph as I have.

on back at side of hand brake

Thanks James, will check in the morning as it's raining now.

Fairly sure mine is about 21/2200 rpm @ 60 mph.

I wonder if you,ve got a Defender T box on your car !.

Del.

Rain stopped and just checked the numbers on the transfer box, only 2 part numbers as listed below, I think I seen where the number should be but the hand brake cable has rubbed it off.

Only numbers I found are frc5415uk & frc6104 there are no other numbers on it, think it's a bit of a recoup of a transfer box and R380 replacement. There are a signs of bad workmanship in the area. Silicon sealant all over the place, bolts missing, bolts rounded off and so on. Think I will have to look for a good gearbox and transfer box out of a crashed 2003 Disco.

whats up with gearbox,cable cant of rubbed it off ,along back under pto cover if not its been ground off ,dont fit second hand gear box without replacing baulk rings and bearings

James, thanks for your help.

Transfer box is 1.4, that's why the revs are so high, now I have to work out what to do on a limited budget.

I am akin the whole family to the Uk in Aug in the Disco and getting married in Nov and now have to fine the money to replace bothe the gear box and the transfer box..

If you were working on a tight budget, what would you do if you were me?

Should I replace the gearbox with one from Ashcrofts and buy a second hand Transfer box and fit it to the back of the R380. Or leave the gearbox in until it goes bang and just buy a Transfer box from Ashcrofts and fit that.

In the next week or so I have to get the clutch replaced and have ordered a plate, cover, bearing and arm from paddocks and the garage I use are going to fit them along with new shocks, disks, pads, flexi pipes & steering damper.

So while it's all apart think I should get the either the gearbox or the transfer box issues sorted.

The gearbox is working but is hard to get into gear without any crunching and the is a whine anything above 30mph. The last time I changed the oil I. The gearbox bits of teeth came out with the oil along with lots of small partials of metal.

The transfer box is working and I don't it whining but I'm not sure. It's under geared and between now and the end of Aug it is going to do 2500+ miles and it's going to cost a fortune in diesel.

Don't really want to fit either box second hand as you can never really tell how good they are until fitted to the Disco. And with my luck I will end up getting someone's trouble.

i would get good used late 300 tdi transfer box ,all have diff lock and are stronger more rugged than q type,and get recon gearbox as its grates while changing means baulkrings are worn and dog teeth on gears will be having there leading edges worn off so would cost more than recon as a lot more parts (gears)would need replacing than would normally be done when reconditioning box,try ringing round theres a few to both boxes around country and good t/box should be about £100,and unless you ask with parts they will sell you cheap **** when there are usually better ranges at not much more ,parts places dont seem to offer the bettter ranges from britpart .bearmach etc,