HDJ81 TD towing a built up 4Runner

[MiniMan85]

I've got a '90 4Runner (SAS'd, 9" lift, ARB, dual transfer cases, etc) to tow from just south of Calgary to Edmonton. I'd guess the 4Runner weighs close to 5000lbs and the trailer would undoubtedly be in the 2000lb range. The distance is between 350 and 400 KM and is very flat and the trailer will have hydraulic surge brakes.

I'm a little leery, as I know the Turbo Diesel 81's are factory rated to tow 7500lbs, but it seams like quite the load to put on my rig. Aside from checking the cooling system, changing the oil, filters, etc. What would you folks suggest I do to prep the truck? Is this something that I should, or shouldn't be doing?

I'd plan on driving back in 3rd gear doing around 100 KM/HR and giving the truck 30 minutes to an hour to cool around half way through the trip.

 

[brownbear]

I think you should have posted this in the 80 series section.

where does it say 7500 lbs tow rating? 5000 with a tow hitch installed seems to be the 80 series standard. 3500 on the rear bumper. I doubt the diesel gives it 2500 more pounds.

Your way over your rating.

 

[lowenbrau]

This thread has some alternate opinions.

https://forum.ih8mud.com/showthread.php?t=97703

 

[MiniMan85]

I think you should have posted this in the 80 series section.

where does it say 7500 lbs tow rating? 5000 with a tow hitch installed seems to be the 80 series standard. 3500 on the rear bumper. I doubt the diesel gives it 2500 more pounds.

Your way over your rating.

The Aussie and Jap HDJ81 Turbo Diesels were rated at either 7500 or 7700lbs. I wouldn't suggest the diesel itself gives it 2500-2700 more pounds, but I am curious as to what other changes there are between gasser's and diesels and why Toyota would rate the the diesel so much higher.

So far I've towed a Nissan Skyline GTR and trailer with it (5500lbs) and the 'Cruiser had no problem with that, besides having a rock hit the turbo's oil return line. No overheating, climbing temp gauge, etc. It sure was slow to get up to speed, but it stopped just fine and once at speed it was hard to notice.

 

[brownbear]

This thread has some alternate opinions.

https://forum.ih8mud.com/showthread.php?t=97703

okay..... I guess I can't doubt it is rated for 7700lbs.

But I wonder why? Is the US DOT rating based on American standards for safety, maybe they feel that 7700 is too high for the size of the truck.

Like you said the tow is on flat ground. Go slow, inspect the tires and couple closely to ensure nothing goes wrong.

 

[MiniMan85]

Well, one big surprise yesterday; the day of the trip. The trailer from "Trailers Unlimited" is just a flat bed. They gave me a couple of chains to tie it down, but that was it.

In any event, I decided to make due with what they gave us and so we continued on. After loading the truck up, I tossed both transfer cases into low and 4L respectively. I first put the long chain through the loops in the back of the trailer and then around the rear bumper, connecting them back onto itself. I tossed the truck in reverse and pulled the chains tight, then chained up the front as best as possible given the resources. Probably not the safest way, but I figured I'd just check to make sure the truck wasn't being pulled off to the left side, due to the pull of the chain (attached only to the trailer's left side in the front), whenever we stopped.

I was a little worried about having the trailer sway around or worse, start a "death wobble", due to having the weight biased too far rear. So I decided to have the truck sit a bit further forward than it could've and run the tongue weight around 15% (est.). The tongue weight was great enough that the rear suspension compressed and the front was sitting at it's normal height. There were no problems with steering response around the worst of corners.

As things go, the trailer DID sway lightly once, but that was easily corrected by tapping the brakes (relatively hard) and then accelerating. Of course, the 'cruiser was underpowered for the size of the load it was hauling, so I generally drove with the truck in 3rd gear. On any light to moderate declines though, I'd toss the truck into OD and build up a bit of speed for the next light climb.

The truck has stock gears and 35's. This worked out (through measuring mile markers) to be 14% off. The average speed for the trip was around "95km/hr" which actually works out to be in the 110km/hr range. The slowest the truck went on the largest of inclines was "80km/hr" which works out to be around 91km/hr.

Every story is better with pictures, so here's one for looking: