Dodge Cummins Diesel Forum banner

1 - 20 of 42 Posts

·
Registered
Joined
·
50 Posts
Discussion Starter #1
Vehicle particulars: recently purchased '16 Longhorn four-door, full 8' bed, 4X4, 3500 HD, 6.7 Cummins (of course), A/T.
Here's my problem; it's too tall! I recently purchased a used 30 foot fifth-wheel, and underneath the overhead is just about the same height as the top of the truck bed. I hope to get around 4 more inches from the trailer axles, but I'd like to drop at least another 2" from the truck, due to some of the quasi-remote areas we hope to get to can cause the overhead and truck bed to make contact. The prior owner didn't like that the rear axle sat higher than the front, so he installed a set of 2" lifts on top of the front coil springs. There's the 2" up front, but how about the back? There appears to be a stack of plates between the bottom leaf and the axle, and that'll gain me about 1-1/4". They look factory. So, my question is two parts:
1) Can those plates be removed without detriment to the drivetrain geometry?
2) What is the spring rate of the rear leafs? Or, how much sag could I expect with 1,100 pounds directly over the axle?
 

Attachments

·
Registered
Joined
·
1,029 Posts
the front coil bracket is aftermarket and can be removed.

the rear 3 cut leaves are OEM.

removal of either would require an aliment.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #3
the front coil bracket is aftermarket and can be removed.

the rear 3 cut leaves are OEM.

removal of either would require an aliment.
An alignment was taken for granted. My main concern is that removing the rear cut leaves would somehow screw with driveshaft angle alignment. It doesn't appear that they apply any sort of angle/wedging to the rear axle, so it's remove away!
 

·
Registered
Joined
·
1,029 Posts
Me personally, I would not remove the rear part. However, make sure the U bolts have enough thread to clamp down without that added part. Or get new U bolts. But it sounds like you know mostly what you are doing. :)



I maybe not understanding the original reason for lowering it.

are you saying the part of the trailer that goes over the bed is ~4" from the top of the bed rails?

If so, then how would changing the ride height of the truck affect that? Would not the proper place to adjust that be the hitch?

Admittedly, I have not towed a 5th wheel. I do own many trailers, all bumper pulls, and I have pulled goose knecks. But I've never had a 5th er yet. So maybe I'm missing the issue.
 
Joined
·
2,539 Posts
High modern trucks are a huge issue with 5th wheel trailers. Just go check out any RV forum.
You can see many guys towing their 5th wheel trailer nose high (which makes for very poor handling), to keep the box side clearance.
The goal is to keep the 5th wheel trainer nearly level.


Lowering the trucks is common to increase clearance between the 5th wheel trailer and the box sides.
Just do a search on "reverse level" on this forum for more examples.

Those 3 blocks under your leaf springs are not cut leaf springs. They are factory spacer blocks and can easily be removed.
I removed mine on my 2wd truck when the truck was nearly new in 2004.
The spacer blocks come out easily. Most guys just mount them on top of the spring pack so the original spring center bolt and U- bolts can be reused.
I didn't do that. I bought shorter grade 8 bolts to replace the center bolts and my U-bolts had enough threaded length on them.

This will reduce the space between the rear axle and the frame rubber bumpstops but you will be fine with your 3500 with the extra over-load springs packs.

If there is still not enough clearance between the truck box sides the 5th wheel trailer, the next step is to raise the trailer.
Options include taller trailer tires, shorter trailer shackles, adding a frame spacer between the trailer springs and the frame.


BTW, unless your 30 foot 5th wheel is a really lightweight, your pin weight will be way more than 1100 lbs.
Just to compare, our 30 foot 5th wheel has a GVW of 10k lbs and the pin weight of the trailer is nearly 2000 lbs.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #6
You can see many guys towing their 5th wheel trailer nose high (which makes for very poor handling), to keep the box side clearance.
The goal is to keep the 5th wheel trainer nearly level.
Definitely! That's the whole intent here.

Most guys just mount them on top of the spring pack so the original spring center bolt and U- bolts can be reused.
Looking back at the second picture in the original post, there appears to be plenty of exposed thread that should more than accommodate the reduced spring pack once those spacers are removed. 'Makes me wonder if that was taken into account from the factory... For sure will verify before final assembly, though.

BTW, unless your 30 foot 5th wheel is a really lightweight, your pin weight will be way more than 1100 lbs.
Just to compare, our 30 foot 5th wheel has a GVW of 10k lbs and the pin weight of the trailer is nearly 2000 lbs.
Looking deeper, the trailer's data sheet shows 1,620 when fully loaded. That might give us enough compression on the rear springs to drop it level (with the trailer axle mods). btw, have you measured the actual sag when your trailer is dropped in place? If it's close to two inches, that might be all I need to get the desired clearance.
 

·
Premium Member
Joined
·
2,138 Posts
That 1,100 pound number was pulled from the trailer's data sheet. At the moment, that's all I have to go by. btw, have you measured the actual sag when your trailer is dropped in place? If it's close to two inches, that might be all I need to get the desired clearance.
That 1100 lb number is dry. Put, food, clothes, water and fuel in it and you will be well over that. Trailers are always listed as dry and it is very confusing and deceiving. You need a bigger truck. 3500 DRW.
 

·
Registered
Joined
·
67 Posts
Have any pics of the 5er hooked up? Have you hooked and measured bed clearance? What hitch are you using and do you have any adjustment room there? What 5er is it?
 

·
Registered
Joined
·
1,918 Posts
i don't see how lowering the rear of the truck will gain you clearance. sure the truck bed will be lower, but when you hook up the 5th wheel the clearance will be the same because of the pin height. or is the pin height adjustable? don't know, i don't have a 5th wheel.
 

·
Registered
Joined
·
87 Posts
as far as weight capacities, see the chart below. keeping this in mind:
Trailer Weight Rating and Tow Vehicle Trailering Weight are calculated as specified in SAE J2807.
Passenger Weight = 300 lb
Options Weight = 100 lb
Trailering Equipment Weight: 75 lb for Conventional Hitch, 70 lb for Gooseneck and 250 lb for 5th Wheel.
Tongue weight: 10 percent of the gross trailer weight for Conventional Hitch, 15 percent of the gross trailer weight for a 5th Wheel or Gooseneck hitch.
Payload and GAWR should never be exceeded and must account for all of the above weights, including the appropriate trailering equipment and tongue weight.
Box Off Body Completion Weight = 80 lb per foot from end of cab to end of frame.

https://www.ramtrucks.com/assets/towing_guide/pdf/2016_ram_3500_towing_charts.pdf
 

·
Premium Member
Joined
·
955 Posts
(1) Generally speaking, coil spacers in the front is a discount approach to level. You may or may not have stock shocks and stock anti-sway mounts and links. Most likely you have 2" longer shocks and stock anti-sway hardware. You almost certainly have stock radius arms. You may or may not have a stock track bar. You likely do ... but you still need to check. Post pics of your track bar, anti-sway hardware, and radius arms and I'm sure someone will chime in on them. Can't hurt to replace the shocks whatever is in there. If they're original, they've been running too tall. If they're replacement, they may not be particularly good ones. It looks like the hole into which the upper stock spring pad is usually indexed might have been drilled out for the bolt that holds the spacers in place. You might need to fit some sort of grommet to that hole to get the spring pad to snap in, at least a little. I know of at least one guy who used a leatherwork grommet to shrink the hole back to stock size. Seems to be working OK.

(2) Remember that if you de-lift the nose only, your tail will actually get taller. I know the plan is to drop it all around, but it can't hurt just to be sure it's said.

(3) I would not re-use the rear u-bolts no matter how much thread you have left on them. The 3500 is tough on u-bolts. They need to be torqued nearly to yield to hang on. Scrap 'em and get new ones.

(4) Read up on alignment issues on these trucks. Factory toe tends to burn through tires and cause some twitchy steering, especially near the crown of a road. Your truck is four years old, and if it's not running on front tires bald on the outer edges someone already had the good sense to adjust toe to near-neutral. You don't have to adjust toe when you make changes to running height all around -- only to caster. As I said, you likely have stock radius arms, so dropping the nose back to stock height will only tend to increase caster. My experience is that our trucks want as much positive caster as we can dial in ... so that's only a good thing.

(5) You don't mention wheels and tires. Stock? If not, you can likely drop another half inch to inch of altitude by going back to a stock size.

(6) If you do want to check your toe-in, you can do it yourself in half an hour with some tape measures, duct tape, and two plumb bobs. Beats the heck out of paying someone $100 to $200 to do it wrong.

(7) If you have a stock track bar, no adjustment is necessary or possible. If you have an aftermarket track bar, find some reference points on the chassis rails and axle and adjust it until the axle is centered. Believe it or not, that might not be where the axle started out. Off-center assemblies are common.

(8) When you drop the nose, you need to loosen the rear radius arm bushing bolts and re-torque them with the weight of the truck on the front axle at the new ride height. If you tighten them down away from ride height, the bushings will fail.

(9) If the truck doesn't already have a steering box stabilizer, get one. They're $150 to $170 and they take half an hour to install, and you won't believe the difference in steering feel. Our front crossmembers onto which the steering box mounts act like big friggin' torsion springs, allowing the steering box to move around way too much. A steering box stabilizer fixes that, easily. Between fixing toe, increasing caster, and bracing the Pitman arm shaft, the feel and stability of the truck both improve dramatically.

All I can think of right now.....
 

·
Registered
Joined
·
50 Posts
Discussion Starter #12
i don't see how lowering the rear of the truck will gain you clearance. sure the truck bed will be lower, but when you hook up the 5th wheel the clearance will be the same because of the pin height. or is the pin height adjustable?
Good question, and it would seem to defy logic when looking at the problem from outside. Yes, you can adjust both the pin and hitch to get the required clearance over the bed. Here's the problem: you really want to have the trailer level during tow. If either the trailer is too low or the truck is too high, you can't get the required clearance and have the trailer level at the same time. So, you either raise the trailer, or drop the truck. Or, in my case, probably both.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #13
That 1100 lb number is dry. Put, food, clothes, water and fuel in it and you will be well over that. Trailers are always listed as dry and it is very confusing and deceiving. You need a bigger truck. 3500 DRW.
As I mentioned in an earlier post, I quoted an incorrect number. Rated fully loaded trailer is shown as 11,500 lbs, with a pin weight of 1,620 lbs. I'm currently on aftermarket tires from the previous owner. They're rated load range "E" with a max weight of 4,080 lbs each at 80 psi. 'Should be okay for weight on the singles.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #14
Tongue weight: 10 percent of the gross trailer weight for Conventional Hitch, 15 percent of the gross trailer weight for a 5th Wheel or Gooseneck hitch.
Dead on, and thanks for the link! Doing the math of 1620 tongue weight by 11,500 trailer weight (loaded) returns 14%
 

·
Registered
Joined
·
50 Posts
Discussion Starter #15
'Quick update: current tires are 285/75-18's, while stock tires would have been 275/70-18's, which only raises the truck by less that 7/8ths of an inch. I'm not willing to drop the cash for a full set of skins for less than an inch. So, tomorrow's plan is to pull the front 2" spacers, but, as StealthDiesel noted, that'll just lead to the tailgate coming up just that much higher. As it sits with the spacers, the truck's just about dead-level. So, it'll soon be followed by the pulling of the shims from the rear springs. Don't worry StealthDiesel, we'll get new u-bolts! There's something unnerving about the thought of all the torque and weight those things have to transmit to turn around and re-use them.
We're still up in the air (pun intended) as to how much the trailer will compress the rear springs, but I have the factory fifth-wheel hitch mounts on order. So-o-o, install those, buy the hitch, pick up the trailer, and see just how nose high it sits. Once that's determined, we then go after the trailer springs to make up the difference. Jeez, nuthin's easy!
 

·
Cummins Dude
Joined
·
2,687 Posts
Like others may have said. Removing the spacers only lowers the truck which will give you a lower nose height on the fifth wheel.
However, it will not do anything for the space between the truck box and fifth wheel nose. Only hitch adjustments will do that.

Being a bit nose high on the fifth wheel isn’t a terrible thing but if you’re trying to gain rear height, lowering your truck completely is the only way to bring up the fifth wheel rear end aside from some kind of lift on the fifth wheel axle sets or reversing the 5th wheel axles. (dropping the axles below the leaf springs instead of stock mounted above). Keep in mind though that reversing the axles changes the dynamics of the fifth wheel by raising the center of gravity and overall height of the RV.

I’m still a bit nose high with the weight on the truck but I put air bags in to stabilize the truck and still have 5” clearance to my box rails. The picture is deceiving because the 5er frame in front drops below the 5er body.

I wouldn’t be taking mine into the backwoods for obvious reasons. LOL
I actually put a wheel on my 5er hitch for low clearance at the rear.
 

Attachments

·
Registered
Joined
·
695 Posts
High modern trucks are a huge issue with 5th wheel trailers. .........
The goal is to keep the 5th wheel trainer nearly level. .............
Those 3 blocks under your leaf springs are not cut leaf springs. They are factory spacer blocks and can easily be removed. ..............
The spacer blocks come out easily. Most guys just mount them on top of the spring pack so the original spring center bolt and U- bolts can be reused. ........
:agree2:

This is what I did on my previous 2007.5 3500 which now has 165k on it and also on my current 2017 3500 which now has 50k on it - to date neither truck has had any driveline issues. I did add airbags to both trucks so when it is loaded I air it back up to level.
Note there is a TSB for this procedure issued years ago by Dodge.
 

·
Registered
Joined
·
1,605 Posts
Take that BS 2" front lift spacer out and lower the front to stock height. Reverse level your truck by removing the three spacer in your other picture. Your truck will look like this when done(my old 2500 with reverse level):

The pic is before and after. Also a pic of our trailer hooked up that had a tonque weight of around 1700lbs.
 

Attachments

·
Registered
Joined
·
50 Posts
Discussion Starter #20
Dogpatch, thanks for your input. If you read back a bit, I believe your concerns were addressed in earlier posts. That's a nice looking rig you have there!

Thanks for the pictures, RadRide! Your post gives me hope.

Saturday brought nice weather, so the spacers came out. Believe it or not, the OE shocks were in good condition! I base that on how the shocks respond, and that there's no sign of any fluid leakage. Removal went pretty smoothly, i.e.; no skinned knuckles! We lost 1-1/2" in height. Once new u-bolts are procured, the spacers will come off of the back. Hopefully, the trailer will find its way to my yard this week, so that's when the real fun begins!
Before and after pictures:
 

Attachments

1 - 20 of 42 Posts
Top