Increase the tow capacity of '99 LX?

[Fivefasts]

Hi All (newbie)

I've had my LX470 for 4.5 years. Easily the best automobile i've ever owned. 238K km now.

I've used it for hauling my boat (5500 lbs dry) from time to time. The trailer GVW is 7000 lbs and i expect i'm close to that which is over the 6500 lb tow capacity of the truck. It tows really well but i avoid big hills. It likes 94 octane when towing.

I'm giving up my moorage, which means i'll be pulling the boat regularly now. I was thinking that i would have to go to a Suburban 2500 or something other family hauler. I'm worried that i'm going to break the LX if i keep pushing it.

Is there any way to increase the tow capacity and keep my LX?

All suggestions welcomed and appreciated.

 

[tlcruiserman]

Hi All (newbie)

I've had my LX470 for 4.5 years. Easily the best automobile i've ever owned. 238K km now.

I've used it for hauling my boat (5500 lbs dry) from time to time. The trailer GVW is 7000 lbs and i expect i'm close to that which is over the 6500 lb tow capacity of the truck. It tows really well but i avoid big hills. It likes 94 octane when towing.

I'm giving up my moorage, which means i'll be pulling the boat regularly now. I was thinking that i would have to go to a Suburban 2500 or something other family hauler. I'm worried that i'm going to break the LX if i keep pushing it.

Is there any way to increase the tow capacity and keep my LX?

All suggestions welcomed and appreciated.

Part fo the towing capacity on your LX is based on the transmission, beef up the tranny and that will increase your towing capacity. also you can add a SC to the 4.7L V8 that will boost your HP also rasinng your towing capacity.

An example I SC my 80 series (a few years ago) and I was able to tow my off road rig and trailer wich were coming in at around 8k originally the 80 series could only tow 5500.

Cheers,

Michael

 

[soberman001]

Part fo the towing capacity on your LX is based on the transmission, beef up the tranny and that will increase your towing capacity. also you can add a SC to the 4.7L V8 that will boost your HP also rasinng your towing capacity.

An example I SC my 80 series (a few years ago) and I was able to tow my off road rig and trailer wich were coming in at around 8k originally the 80 series could only tow 5500.

Cheers,

Michael

Yes, everything that he said, plus brakes. Even with trailer brakes, if you get into a long downhill, you can over heat brakes. Think about an upgrade to a vented and cross drilled brake rotor and appropriate pads for that type of hauling.

 

[RogerCruiser]

What does SC mean?

 

[farinvail]

bad juju pulling a trailer that weighs more than your truck. I'm just sayin. Like a 5year old child walking a Great Dane.

 

[Trunk Monkey]

SC=supercharger, which hasn't been available for the 100 for several years.

I'd suggest airbags on the back end for sure. They make a cheap kit, like $100, that installs easily. Then, when you're towing, you add air to the bags. When you're not, you deflate them.

 

[Skidoo]

Bigger transmission oil cooler, might want to get transmission oil temp gauge to keep in safe range. If road is flat, not too hot out, and you take it easy, may not need to modify it much. But if you have to tow in the heat of the day, uphill, with the pedal to the metal, prepare to have wallet vacuum cleaned.

 

[scottm]

For short, flat hauls I wouldn't worry about it. Long hauls or hills, a little worriesome, but you be the judge. I had airbags in my 80, towed a pretty big trailer a lot, the bags made a world of difference. Cheap, easy to install, mine were Airlift. My brother towed a crazy big trailer all over the country with his 80, again the rear airbags and cautious driving were plenty good.

I'd certainly plan on checking brakes and such more often, change the diff fluids occasionally, transmission fluid if you can.

 

[Fivefasts]

how do airbags interact with suspension leveling system?

Well im pleased with the responses.

The truck stays pretty level with the existing sytem, but maybe thats putting too much pressure on an item thats expensive to fix.

I like the idea of a transmission temp gauge to keep an eye on it. Then, if it looks like it runs hot, i'll increase the size of the cooler.

How do you strengthen the tranny? Sounds mighty expensive.

 

[RoderickGI]

The truck stays pretty level with the existing sytem, but maybe thats putting too much pressure on an item thats expensive to fix.

Correct. The AHC is probably running at a much higher oil pressure in order to maintain the vehicle level, which means the oil pump has to work harder, and the Hydraulic Accumulators will have more oil in them, compressing the gas more, which will mean less travel available to the suspension. If you measured the hydraulic pressure in your AHC when the boat is connected up, you may be surprised. You may also want to measure the weight on the tow ball to see if it exceeds the specification, and by how much.

I run OME (Old Man Emu) 862 springs on the rear to carry extra weight, since they are the same height as the original springs. They change the ride, but carry the weight. Air bag springs would work well also, and have the advantage that you can use them only when required.

All the other stuff people mentioned above may be requried. I would certainly want to know that the trailer brakes were good enough to stop the trailer!

How do you strengthen the tranny? Sounds mighty expensive.

You get an EXTREME Transmission They reckon they are still working on a "Toyota Landcruiser 1998-01 V8 A343F - 4 speed electronic transmission", and I haven't checked if that is the same as our Lexus transmissions. EDIT: I just checked, and my 1998 Lexus uses an A442F transmission, which is the one they have already developed. Yours is probably the same, as I don't think the transmission changed until 2000.

 

[2000UZJ]

bad juju pulling a trailer that weighs more than your truck. I'm just sayin. Like a 5year old child walking a Great Dane.

 

[Yotato]

While the above suggestions are great if you are towing within the GVWR, you will want to evaluate where you are at so you know what you want to realistically achieve with your LX without spending a little money at a scale.

Before dumping any money into your LX, get your boat (loaded with fuel, food and gear for your average trip) and trailer properly weighed at a commercial scale and see if you are within the GVWR and GCWR.

5500 lb dry boat (boat weight only without gear and fuel).
1000 lb trailer (guess).
8.3 lbs per gallon of fuel (avg on small craft is 65 gallons or 540 lbs.)
You are already over 7000lbs without the gear and people in your LX (Subtract 1500 lbs if you meant that 5500lbs was weight of boat, trailer, fuel, and gear outside of water -you will still need to weigh yourself and passengers and gear inside your LX to see if towing is doable.).

Here is a checklist to help you out: Worksheet for Trailer Load and Balance

Your vehicle is engineered to tow within the GVWR, and airbags, better brakes, superchargers, are a good start, but you will be better off getting a tow vehicle for your boat if you have exceeded your GVWR. Towing is about you and your vehicle safely handling the load in it's engineered state. Good luck.


HowStuffWorks "Is it possible to increase the towing capacity of a truck?"