Nuts & Bolts: Drivetrain Swap in a 1989 Range RoverPosted in How To: Transmission Drivetrain on October 22, 2015
British Gone Bad
Against all common sense I picked up a 1989 Range Rover. I guess I always wanted one, and the $300 price tag was right. The floorboards are bad, it’s dented and abused, and someone stole the headlight washers, but it’s mine now. Besides, three of the tires were good and I needed them for my truck. It even kinda runs! It won’t rev over 1,800 rpm if I put a brick on the pedal, and it sounds like a pan full of marbles. But there isn’t any oil in the water, or vice versa. I’m not having much luck finding another 3.8 (or is it 3.9?) V-8 in the junkyards or online. I’m not really willing to do a rebuild either. What I really want to do is swap in a junkyard 4.3 from a Chevy truck or S-10. I’d even run a carb and ditch the electronics altogether. It’s a beater toy that will never see the highways again, so emissions aren’t an issue. Does anyone make an adapter for the auto trans? If not, what are my trans swap options? The transfer case has an offset rear output like a Dana 18, so that is going to limit my options for a complete engine-trans-transfer case swap. I’m open to just about anything. Think cheap, simple, and easy to find. I’m an amateur fabricator with a decent shop, so I can build mounts and such, but machining isn’t part of my skillset yet.
A British car project. What could possibly go wrong? While the British are awesome and have great accents, I must confess that I have a general aversion to the British and their ability to make vehicles in general and 4x4s specifically (ever heard the punchline to the joke about why the British don't make refrigerators?). But I also appreciate people who dare to be different. While many people (myself included) would question your sanity putting time and effort into such a rough vehicle, it is also widely acknowledged that neither logic nor sanity are common traits among those of us here on the left side of the pond.
All kidding aside, Range Rovers are kind of cool because they are different. I wouldn't bother finding a stock donor engine unless one fell into your lap for free because the electronics of late-1980s British technology must be a nightmare (much as it was on contemporary domestic vehicles of the time). Your best bet is to start with the shell and work from there, and by that I mean a complete drivetrain swap. Advance Adapters (advanceadapters.com) does offer a few adapters that may mate whatever transfer case might be in your Land Rover to some of the more common domestic transmissions. However, these are pricey.
Considering this is a project and an off-road toy, you're better off swapping everything, including the rear axle, for components that are more widely supported by the aftermarket. A 4.3L Chevy with a TH700-R4 transmission and NP231 transfer case is a great option due to all of the aftermarket support for this swap, but this gets you a transfer case with a centered rear output and a front output on the wrong (driver) side. This means swapping the rear axle and the transfer case as well. Should you not be able to adapt the Rover transfer case, you will be able to adapt whatever transfer case you choose with a passenger-side drop. Your only non-exotic offset T-case option is a Dana 18, but there are some others from Toyota. Should you choose to go with a centered rear output case, measure the width of the stock axle and start researching what might work that's cheap. I would venture to guess that a Ford 8.8 out of an Explorer, van, or F-150 would be close enough to the right width, and these are cheap, well supported, and available everywhere.
Cut, hack, and modify as necessary to make the above modifications fit. You can probably salvage the front axle and avoid doing a lot of suspension and steering work by upgrading the axleshafts and regearing to match the rear, but then again, the wheel bolt patterns will be different. Regardless, you might consider keeping the stock suspension design, as it is actually really well thought out and performs great. Beyond these basic parameters, go with whatever you can scavenge cheap, and let us know how it turns out.