Towing capacity of my v8 XJ?

[blistovmhz]

Given there are NO posts in this section, I don't have high hopes for a lot of response, but whatever. It's just a passive question.

I'm pretty much done living in the city, and I think houses are generally ridiculous. I need a shop space, a place to sleep and cook, and a shower. I really should just be buying some property out somewhere and living in a trailer. That being considered though, I'm wondering how much I can realistically pull with my XJ.

98 XJ, 5.3L LM7, 4l65e, 4.56 gears (locked), 35x12.5" shoes, 6" lift (front long arm, rear 63" chevy 3.5" lift springs), blah blah blah.
I know the rear end would need some support if someone even stands on the back, so i'd be looking at some air lifts for hauling, but this isn't like, something I'd be hauling often. Maybe once every few years.

What realistically, can the 5.3 pull with my gearing and tires? Ignore my rear suspension as I can always temporarily beef it up.
I've been waffling between building up a a box truck or RV for a full time home, but I hate having to maintain two drivelines (one for Jeep and one for home), plus if I end up moving a long way, I really don't want to have to have someone else drive my Jeep alongside me, thus, the trailer seems like the best option unless I can find a sweet deal on a 24' box big enough to also haul the Jeep.

I'm thinking I should be safe-ish if I stay under 10,000lbs, which should be VERY easy to accomplish if I build the trailer up myself. The donor vehicle (for engine) was rated to 11,600lbs.

 

[ROBZ95Xj]

It didn't matter what the donor vehicle was rated for. A stock xj was rated for 5k. I'd go less then that with the lift

 

[blistovmhz]

I think it does matter. My XJ is no longer even remotely a Jeep. There's almost nothing Jeep left on it. It's 5000lbs of metal. Yea, the lift makes towing more sketchy, but again, I can compensate for that when the time comes. I can always lower it or throw a massive leaf pack or air-bags under if when I need to tow (which really, would only be every few years at most).

The drivetrain, in the donor vehicle, was rated at 11,600lbs. Yea, the stock XJ was only rated for 5000 for very good reason, but most of those reasons are no longer valid on my rig. I have a longer wheel base, way more mass, an extra 150hp, triple the stock cooling at least, etc. The only thing I'd be concerned about right off the bat, is my axles, which will probably be swapped out to tonnes to accommodate heavy towing.
I've seen guys in lesser rigs towing 8000lbs trailers/boats pretty safely (after increasing the GVWR) with a 4.0L. I figure if they can do 8000, I can do at least that.

I know guys in the US are typically way more hardcore about their rigs and towing than anyone up here (I'm the only one with a v8 XJ for a 1000km as far as I know).

Really just trying to get a feel for the max other guys have done in their "rigs that used to be XJ's". I know the suspension is a major deal breaker, but it's easy to fix when the time comes.

 

[ROBZ95Xj]

Even with your wheelbase longer then a stock xj, its still a short wheel base.

 

[TRCM]

I think it does matter. My XJ is no longer even remotely a Jeep. There's almost nothing Jeep left on it. It's 5000lbs of metal. Yea, the lift makes towing more sketchy, but again, I can compensate for that when the time comes. I can always lower it or throw a massive leaf pack or air-bags under if when I need to tow (which really, would only be every few years at most).

The drivetrain, in the donor vehicle, was rated at 11,600lbs. Yea, the stock XJ was only rated for 5000 for very good reason, but most of those reasons are no longer valid on my rig. I have a longer wheel base, way more mass, an extra 150hp, triple the stock cooling at least, etc. The only thing I'd be concerned about right off the bat, is my axles, which will probably be swapped out to tonnes to accommodate heavy towing.
I've seen guys in lesser rigs towing 8000lbs trailers/boats pretty safely (after increasing the GVWR) with a 4.0L. I figure if they can do 8000, I can do at least that.

I know guys in the US are typically way more hardcore about their rigs and towing than anyone up here (I'm the only one with a v8 XJ for a 1000km as far as I know).

Really just trying to get a feel for the max other guys have done in their "rigs that used to be XJ's". I know the suspension is a major deal breaker, but it's easy to fix when the time comes.

Not sure about up there, but in the US........

No matter what you think, the law & your insurance company go by the sticker on the door which is tied into the VIN.....so even if you think it ain't a jeep anymore, they say it is.

And no matter what you have seen, the ONLY way to legally increase your GVWR, is to have the vehicle recertified....and that costs a pretty penny. Air bags, heavier rated springs, new suspension...none of that means squat when it comes to increasing your GVWR.

I looked into it several years ago, and it was 60% cheaper to just buy a brand new fully loaded diesel dually 4x4 than to get my truck at the time recertified as a 1 ton vs 1/2 ton, even thought it had a 1 ton suspension under it.

What you SAW someone tow, and what was safe are not the same. Just cuz they didn't wreck doesn't mean it was safe. Get in an accident towing 8000 lbs behind a cherokee, and your insurance company will drop you & not pay, and the law will stick it up your kiester for being overweight.

 

[GordoSmasho]

Not sure about up there, but in the US........

No matter what you think, the law & your insurance company go by the sticker on the door which is tied into the VIN.....so even if you think it ain't a jeep anymore, they say it is.

And no matter what you have seen, the ONLY way to legally increase your GVWR, is to have the vehicle recertified....and that costs a pretty penny. Air bags, heavier rated springs, new suspension...none of that means squat when it comes to increasing your GVWR.

I looked into it several years ago, and it was 60% cheaper to just buy a brand new fully loaded diesel dually 4x4 than to get my truck at the time recertified as a 1 ton vs 1/2 ton, even thought it had a 1 ton suspension under it.

What you SAW someone tow, and what was safe are not the same. Just cuz they didn't wreck doesn't mean it was safe. Get in an accident towing 8000 lbs behind a cherokee, and your insurance company will drop you & not pay, and the law will stick it up your kiester for being overweight.

This is truth.

Most of the time vehicle towing capacity is based on stopping power not pulling power. Lift and tires deminish this abillity so take that into consideration.

 

[blistovmhz]

Yea, I'm not exactly sure how it works up here, but I hear guys re-certing for higher GVWR all the time, on pretty bomber vehicles. Lots of guys increased their GVWR just to avoid having to do air care (which until this year, was all vehicles under 5000lbs GVWR).
Either they're all full of shit, or it's just less of a process up here than down there.

As for brakes, with my current setup I know I can safely stop about 6000lbs, without trailer brakes. I won't pull that much right now because yea, I understand the difference between what's possible and what's necessarily a good idea. I'd be throwing tonnes on if I was going to tow anything bigger than 5000lbs right now, but my stopping power is substantially better than a stock XJ, even on the 35's. My brakes would be painfully strong on 31's . I can lock up my 35's as it is.
As for pulling vs braking, I absolutely agree. Even my 4.0L could pull 6000lbs trailer with 35's without a struggle. Hell, I barely even noticed 3000lbs. With the V8, I can't imagine 10k being too much, except perhaps on very long steep climbs.

 

[TRCM]

Whatever........not sure what you 'hear about recertifying", but when I looked into it here in the states, I was told it would cost between 75 & 90 thousand dollars......so I kinda doubt it is done 'all the time'.

I've had 2 full sized 1/2 tons truck lately, a Silverado with the 5.3l engine, 3.73 gears, & the heavy duty towing package, and a Ram 1500 with the hemi, 3.92 gears, and the heavy duty towing package also..........and 2 different 1/2 ton 79 Dodge Ramchargers, both with towing packages & gears, and a healthy 360 engine. All were built & designed to tow, and none of them were rated for more than 10,000 lbs, even WITH a WD hitch.

Only truck I have ever owned that was rated for more was a 97 Dodge 3500 4x4 5 spd 4.10 geared 12v CTD, and it was only rated for 11,000 lbs GVWR, 13,000 towing capacity, and that is a 1 ton dual axled truck. Not a modified jeep.

My dually was BUILT to tow from the factory, and it was only rated for 3000 lbs more than you claim you should be able to tow. :doh:

Good Luck & be safe........................

 

[blistovmhz]

Maybe newer models offer higher capacity? The 2015 S1500 base with the 5.3L is 9000lbs, and 12,000lbs with the towing package (same engine, bigger brakes and stiffer suspension).
That said, I'm just using 10,000 as a baseline as I know my motor can deal with it. I'm starting there and working my way down to the weakest link.

 

[ROBZ95Xj]

You can polish a turd but at the end of the day its still a turd. It's still gonna be a xj with a short web(compared to a fullsize truck) it will never be safe to tow overseas 5k and don't ever think you can safely tow 6k without trailer brakes.

 

[GordoSmasho]

Being able to lock up your tires should not be a goal to look at... Nor does it help you stop. Not trying to be an ass. But i hate when people grab onto info like that as a standard to aim for.

Being able to lock up your tires doesn mean you would still be able to do that at the end of a long downhill grade with an extra 6k lbs behind you. Those pads will be cooked for sure. And then an emergency happens and your screwed.

 

[TRCM]

Maybe newer models offer higher capacity? The 2015 S1500 base with the 5.3L is 9000lbs, and 12,000lbs with the towing package (same engine, bigger brakes and stiffer suspension).
That said, I'm just using 10,000 as a baseline as I know my motor can deal with it. I'm starting there and working my way down to the weakest link.

That change from 9000 to 12000 is not just the towing package, that is with proper equipment...meaning a Weight Distributing hitch, trailer brake controller, 6.2l direct injected engine, and the bigger brakes/better transmission. And you shouldn't really use a WD hitch on a vehicle that has no true frame.

The only way the 1500 gets to 12,000 lbs is with the 6.2l engine, max trailer tow package, and 2wd short or standard bed. 4wd is slightly lower.

Per the 2015 trailering guide on the chevy website, the direct injected 5.3 engine/truck is only rated for 11,000 lbs when it has the max trailer package in a 4wd vehicle.

Problem is, you don't have that engine. You have an older model, with less power & torque, and therefore an even lower rating.

It's obvious you're gonna do what you want no matter what we tell you, so go ahead and do it. Please just stay north of the border so I don't have to worry about pulling up next to you overloaded on the highway.

 

[jbsjunk]

I think it does matter. My XJ is no longer even remotely a Jeep. There's almost nothing Jeep left on it. It's 5000lbs of metal. Yea, the lift makes towing more sketchy, but again, I can compensate for that when the time comes. I can always lower it or throw a massive leaf pack or air-bags under if when I need to tow (which really, would only be every few years at most).

The drivetrain, in the donor vehicle, was rated at 11,600lbs. Yea, the stock XJ was only rated for 5000 for very good reason, but most of those reasons are no longer valid on my rig. I have a longer wheel base, way more mass, an extra 150hp, triple the stock cooling at least, etc. The only thing I'd be concerned about right off the bat, is my axles, which will probably be swapped out to tonnes to accommodate heavy towing.
I've seen guys in lesser rigs towing 8000lbs trailers/boats pretty safely (after increasing the GVWR) with a 4.0L. I figure if they can do 8000, I can do at least that.

I know guys in the US are typically way more hardcore about their rigs and towing than anyone up here (I'm the only one with a v8 XJ for a 1000km as far as I know).

Really just trying to get a feel for the max other guys have done in their "rigs that used to be XJ's". I know the suspension is a major deal breaker, but it's easy to fix when the time comes.

Did you get rid of the uni-body and the stock suspension mounting points? It's still rated for 5k. It's still a Jeep. Long arm or not.

 

[blistovmhz]

That change from 9000 to 12000 is not just the towing package, that is with proper equipment...meaning a Weight Distributing hitch, trailer brake controller, 6.2l direct injected engine, and the bigger brakes/better transmission. And you shouldn't really use a WD hitch on a vehicle that has no true frame.

The only way the 1500 gets to 12,000 lbs is with the 6.2l engine, max trailer tow package, and 2wd short or standard bed. 4wd is slightly lower.

Per the 2015 trailering guide on the chevy website, the direct injected 5.3 engine/truck is only rated for 11,000 lbs when it has the max trailer package in a 4wd vehicle.

Problem is, you don't have that engine. You have an older model, with less power & torque, and therefore an even lower rating.

It's obvious you're gonna do what you want no matter what we tell you, so go ahead and do it. Please just stay north of the border so I don't have to worry about pulling up next to you overloaded on the highway.

I have an 05 LM7 5.3L with an 05 4l65e transmission. This combination is used in the base model rated at 9000lbs (for the 2005 year), upgradeable to 11,500 with tow package. No, I'm not going to just pull whatever I can pull, regardless of input, which is why I'm bringing it up. I knew I'd get heaps of "NOOOOOOOO!! THEY'RE ALL GOONA LAUGH AT YOU!!!!" , but some good information has come up and I've learned a few things.

Did you get rid of the uni-body and the stock suspension mounting points? It's still rated for 5k. It's still a Jeep. Long arm or not.

I didn't get rid of the Unibody, but it is built stronger than any stock framed vehicle I've come across other than perhaps a unimog. There's a reason my XJ is as heavy as a tow rig. Entire uniframe rail is plated substantially thicker than say, the frame of my roomies pickup (about 3x thicker) and is also well braced and will soon also be caged.
All the stock suspension mounts are long gone. As I said, this is no longer even remotely an XJ aside from the fact that it's sorta shaped like one. All suspension mounts are boxed 3/16 or 1/4, and tied into the plating. I know how flimsy the stock XJ stuff is for anything other than mild wheeling. I've got old stock mounts torn off to prove it . Point is, my XJ isn't going to go full taco before most 1/2 and even some 3/4 tonnes will.

The issues I see are the short wheel base (longer than an XJ, but shorter than a decent tow rig), possibly braking force (again, easily stronger than any 1/2t truck, based both on pure math as well as real world testing), and the rear suspension would been to be supplemented as it's just not built for towing (but a few overloads and an anti-roll bar would stiffen it up real good).

Also again, I'm not trying to pull 12,000lbs. I said that is the number that comes with my
driveline so I know I can easily drag that much behind me. It's a baseline to work from, and I'm not asking "can I pull 12,000lbs, ps. I don't care what you say I'm going to pull 20,000". I'm asking for real world issues I'd have to address to safely increase my towing capacity, and figure out how far I can push it (safely). Once I have a number, I'll either build a trailer to match, or if the number is too low, I'll worry about the tow rig some other day and build whatever trailer I want.

 

[blistovmhz]

Being able to lock up your tires should not be a goal to look at... Nor does it help you stop. Not trying to be an ass. But i hate when people grab onto info like that as a standard to aim for.

Being able to lock up your tires doesn mean you would still be able to do that at the end of a long downhill grade with an extra 6k lbs behind you. Those pads will be cooked for sure. And then an emergency happens and your screwed.

I use the "can lock up tires" only as evidence to myself, that my brakes are working correctly and can deal with my mass. At 5000lbs and 35's, stock XJ brakes don't even begin to slow me down and there's not a chance they could get anywhere near lockup.
I think using lockup as a baseline verification that your brakes can deal with your mass, is a mostly reliable method of assessment. If I couldn't lock up my tires, I know nothing. Maybe they're doing just enough to stop me efficiently, maybe not. Full lock means I have more than sufficient braking force.

I agree. Being able to lock up says nothing for overall braking performance. I can lock up the brakes on my bike as well, but I also know that if I'm hard on them for several KM down hill, they'll fade. In my case, the only time I've managed to get mine to fade is on an extremely hot day of non-stop, mostly down hill, high speed wheeling. Fronts started fading while rears were still doing an acceptable job. This however, is most probably due to using stock type WJ/Akebono pads, which just weren't up to this sort of abuse. Will be swapping out with some BlackMagic pads shortly. Only reason I haven't done so is because I want to do it when I'll be able to test them on the only run that's ever managed to over heat my brakes. I want to push them beyond where my WJ pads faded.
Incidentally, to give you an idea of how much abuse was thrown at the Jeep that day, all 4 shocks (14 and 12" 5125's) were too hot to touch.

Of all the vehicles I've owned and built, and of all the vehicles I've driven or ridden in, my XJ stops ridiculously well. I'd pit it against my civic any day on the street. Everyone who's ridden in it is blown away by how fast it accelerates and decelerates.

 

[jbsjunk]

You can put the power down all day long, but can you control it? Not in a short wheelbase uni-body XJ. That is not a truck. You asked for professional advice and you turn it all down. Just keep it up North.

 

[ashmanjeepxj]

On paper its only legal to tow the same as a stock XJ, Your insurance might not cover you if you have an accident and tow more than OEM rating.

Axles are not rated for the weight you want to tow, weight carrying, brakes and gears.
Im guessing your tires are not D or E-rated to tow, Are you rims 15in? they also would not be rated for higher weight.
Cooling of your drive train swap may not be up to the task that the "towing package" came with. Cooling for normal use in the XJ is hard with a V8.
What is your hitch rated for, modifying your hitch to the unibody to make it stronger is also an insurance liability.

Buy a dodge cummins 3/4ton and be done with it. XJs go on trailers not in front of them.

 

[DieselSJ]

Sorry we did not give the answer that you wanted. You aren't going to take our advice, so stop arguing an go do whatever you are going to do. Just remember that you are driving a unibody station wagon, not a full frame truck. You actually hurt your towing capacity with your lift and tires. But you already have your mind made up that we are all wrong.

Here is my point of reference - I have a 1987 Grand Wagoneer - from back when Jeeps had full frames. Factory tow rating was like 5000 lbs. Now with my 6.5l turbodiesel and 14 bolt rear, I can pull A LOT more than 5k lbs. The thing will greatly outpull my 2001 Super Crew. But even though it has more power and can pull that much, my Super Crew is a way better tow vehicle for pulling my 7K lb trailer. The short wheelbase (which is longer than your wheelbase) and light weight (and it weighs more than your Jeep) make it a hairy ride when you get a gust of wind or passed by a semi. Heck, even with trailer brakes a fast stop puts it on the edge of control. My bigger, heavier Super Crew does not have those same problems - it just has less power than my SJ.

But you go ahead and pull your 10K lb trailer because "you know" your mods make it some super duper tow rig.

 

[WTF]

the 2005 trailblazer had the same engine/ tranny combo (5.3l/4 spd auto) and was only rated to tow 5k lbs.

I would think this is the most comparable to what you've built.

The tow ratings have more to do with the chassis specs (suspension, wheelbase, curb weight) than it does the powertrain and brakes.

 

[blistovmhz]

the 2005 trailblazer had the same engine/ tranny combo (5.3l/4 spd auto) and was only rated to tow 5k lbs.

I would think this is the most comparable to what you've built.

The tow ratings have more to do with the chassis specs (suspension, wheelbase, curb weight) than it does the powertrain and brakes.

This makes more sense to me than the 20 responses insisting that I'm going to tow a 20,000lbs trailer regardless of what anyone says . Thanks. Makes me insane when you ask a question and 10 guys show up to insist that what you're "going to do regardless of input" won't work. If I listened to that every time, I wouldn't have a 350hp lifted XJ getting 25mpg (with roof basket and carrier removed).

Yea, I know the short wheel base kills us, but I'm wondering how much I can wiggle around it by beefing up suspension/chassis/whatever. The heaviest I've pulled on the street was around 6000lbs for a few blocks, just to get an idea of what it'd feel like. The 4.0L really didn't struggle with the load, though my brakes certainly did, but at least at low speeds (around 50-60km/h) everything felt pretty stable. Throughout this thread I've stated repeatedly that I don't have a top end figure in mind, and that this figure is what I'm trying to figure out, but yea know, any discussion about doing something a stock Jeep wasn't designed to do is always met with confusion and anger (much like trying to buy parts at my local parts shop, and the sales guys ****ing argue with me that the part I'm asking for won't fit on my Jeep *sigh*.

Ultimately, my digging into increasing GVWR has given me my answer anyway. Here in BC, increasing GVWR for non-commercial applications is retarded. You just go to your insurance provider and have them increase it. I have no idea what the actual law says, but my insurance company says they just bump it up and we're done. This however, won't work for me either way because of air care.
Previous to this year, air care was only required for vehicles with a GVWR >5000lbs. I managed to pass just fine with the 4.0L, but I'd actually held off on the v8 swap precisely because it would not pass, despite being more efficient and having less emissions. Our air-care here is ****ed. They don't care if your emissions are below average, they want to see that they ARE average. If you score too low, automatic fail. As of this year, >5000lbs are exempt, and >5000lbs air care is required, and there's no way I'll pass unless I absolutely destroy my engine, so I'm stuck with the sticker on the door, so I guess I'll just see what I can do with 5000.