Has anyone put a 1.667:1 or a 1.4:1 transfer box in a discovery? If so what does it drive like? I do a fair bit of towing and I find pulling away difficult with any sort of weight in the trailer. As it will need a new gearbox soon I'm thinking I could be wise to change the t box.
Motorways and driving over 50 are not needed where I live.
I did transfer box rebuild from Ashcroft, and due to some circumstances I opted for 1.41 ratio on high gears.
It drives smoother, accelerating easier and feels like driving’s with factory tires, except torque converter lockup.
How does it cope when it's in low then? Only does about 20mph in faith gear.
This is not affecting low gearing at all.
Bigger tyres would cause much more harm than a remap for a Td5.... a good remap has no ill effects for the engine no matter of mileage, on the contrary, while bigger tyres = higher EGT which kills the engine slowly...that's a fact... to not speak about how gutless it will be with bigger tyres and no remap
Regarding the ill effects of remap: why would you say there are no bad effects on the car regardless of mileage, when Pete Bell say it is not advised to do it when engine has big mileage?
now, I would like to explain something and ask you opinion then:
I have the Discovery 2, with automatic gearbox. Fitted 33 tires, which caused the engine to work harder. Fitted an roof rack, bull bar and winch. So that means that the engine was forced to work hard.
Now, you have to compensate the added load, which means you can do that by changing the diff ratio. Otherwise, you can change the transfer box ratio, which will have almost the same effect except you do not remove the stress from propshaft and you do not touch the low range gearing.
after fitting 1.41 transfer box, I observe the engine acceleration is nearly as before fitting bigger tires. It drives easy on highway in 4th, when earlier I was driving only in 3rd with factory transfer box and 33 tires...
only one unsolved issue now, the Torque Converter lockup is not working. But I am not sure why, because when I fitted the transfer box, I also removed the transmission, replaced the flex plate with a HD one, changed the oil, some seals etc...
I can also expect that I touched something in the transmission sump as well...
so, in conclusion, I disagree that these mods are against the engine lifetime, but, I consider that these mods may not be the only one required.
I will talk to Pete Bell regarding mapping and ask again his opinion.