2019 Isuzu D-Max Pricing and Specs

Sandy conditions are incredibly hard on every aspect of a four-wheel-drive. The sand itself constantly shifts under the tyres and clings to them as well, dragging them down and making the engine and transmission work very hard to maintain progress. You may have already noticed that you use a lot more fuel in sandy country and it’s all because you need to be constantly making more power to maintain speed than in normal conditions. Turbocharged engines and automatic transmissions, in particular, can get very hot very quickly in sand.

With that in mind, it’s very possible that something in the driveline got hot enough for the car’s computer to go into limp home mode to protect what ever was hot from damage. Limp home mode often involves limiting engine revs and turbo boost, both of which contribute to heat production. This would explain why the car would not climb a crest but came good after a break.

Problems like these are hard to diagnose remotely, as there's a lot going on in a modern gearbox. But, conventional wisdom suggests that a noise followed by a series of failures of the same component (the oil seal) means something inside is bent or damaged.

The noise is potentially being caused by something misaligned and rubbing or a damaged bearing, and the blown oil seal is the eventual result of the damage/swarf/heat/friction that results. The other possibility is that the rear gearbox seal is being destroyed from the other end of things, as in the tailshaft. A bent tailshaft could set up harmonics, friction or vibrations that could kill the seal, but you'd imagine there'd be a vibration through the whole vehicle at speed if this was the case.

Your vehicle is under warranty (six years of it from new) so make sure the dealer is aware of the problem and their obligation to fix it.

Warranty or not, if the workshop that serviced the car broke the cover, surely it’s up to that business to fix it. Separate to that is the fact that the car is still well and truly under warranty, so that makes the problem Isuzu’s to some extent, also.

To be honest, these plastic covers are one of the more useless additions to modern cars and really only serve to make the underbonnet area look a bit neater when you open the bonnet. In fact, they allow packaging engineers to be a bit lazy as they can cover a messy layout. The best advice is to get hold of a new cover under Isuzu’s warranty and store it in the shed. Then, when you’re ready to sell the car, fit the still-new cover so it looks neat and tidy for would-be buyers. The vehicle will run fine without the cover.