I have a 1990 Toyota Sunrader that came with so many safety and mechanical deficiencies I feel like I'm reinventing the wheel. The frame is too light. The 3VZE is a 3VZE. The fiberglass body had no frame. It was fiberglass, 3/4" styrofoam, and 1/4" luan plywood. Seatbelts screwed to plywood, you get it. I do love my Yota. My parents bought it new, and I have started creating my idea of what it should have been from the get go. It has 46,000 orriginal miles. New timing, waterpump, hoses, wires, etc. The crossover manifold has been removed. What needs to be done next before finish wiring and paint is a suspension upgrade. I am open to suggestions, but there are qualifiers. I will be adding about 2,000 lbs of upgrades to the coach. ie batteries, solar panels, steel frame,etc. It has to be lifted enough to support 16" 10 ply tires. I may want to go 4x4 maybe with torsion bar removal or not. Thoughjt about a narrowed 3500 rear axle from a doner, I do like the duallies, but mine are 14" rims.I keep buying lottery tickets to allow the purchase of that new Cummins QSB 4.5, They are only 15-18K right now. Sorry dreaming! How do I end up with big brakes, proper rated tires, matching bolt patterns. Strong enough axles and spindles that take the extra weight ?

 

So many issues to discuss here. First off, forget about the diesel...that one anyways....it is 3 times the weight of what you have tipping the scales at close to 800 lbs. Your frame will never support that or the amount of torque the engine puts out let alone fit in the engine bay without major sheet metal work. Axles can be custom built. I'd recommend a more simple Dana 60, there is a lot of support and parts out there for this axle. Converting to 4x4 is not all that hard in my opinion, but that's what I used to do for a living and have done several of them. A 4x4 front end I would recommend would be a Dana 44 narrowed down from a full size Chevy to match the bolt pattern. . A Dual shock set-up can be had both front and rear without too much of a problem. Now the engine you have is a big turd in the Toyota world. The 3.0 has a few issues with the block cracking and such. The 4 cylinder 22RE had almost the same amount of power and got better mileage. Throw a turbo on it and you had a winner. Converting the 3.0 to a 3.4 is a step in the right direction. This is done all the time and there are lots of how tos that are available. NO mention of which transmission you have.

 

The tranny is the automatic with electronic overdrive. I have a buddy that put a dual shock setup on his fj. Not really interested in the solid front axle but wonder about how to get spindles that have the 6 lug bolt pattern that would match the GM 3500 6 lug rear axle, so the spare could be used front or back. Would you go with a two tire rear suspension? The 16” tires in 10 ply are rated to carry almost twice the weight of the 14” 10 ply Vanco trailer tires it has now. Finding a donor 4 runner 4x4 would take care of the better engine and transfer case, but I don’t think it would have one ton brakes or six lugs. I would like to keep the rear Firestone air-ride system that I have now. Great leveling with left and right control. I will need about 3-4” lift in front to fit the 16s, but should not need big travel. Dirt roads but no rock climbing. It is 21’ long. Any ideas?

 

You're not going to find any 3500 axle that is 6 lug. 3500 series trucks (1 tons) are 8 lug, especially duallys and some HDs are 10. You mentioned maybe converting to 4x4. Don't know of anybody converting to an 8 lug ifs torsion bar suspension on a Toyota frame. Just not done. Straight axle is the most durable and easiest to go with. Maybe a little more research is needed on your part before taking this on.