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'21 AT4 3500 SRW crew long box 5th wheel clearance issue

11K views 40 replies 17 participants last post by  MRAllen 
#1 ·
Hi,

I just traded in my '15 SRW long box for a '21 AT4, am sooper stoked.. BUT:

on my new truck the bed rail to 5th wheel clearance is way too tight ! it was marginal on the previous truck and I didn't think it would be that different (doh). Now I cant take my 5th out of my driveway !! Trailer already had axles flipped already has the biggest tires it can on it it can fit and pin box is lowered (which raises the front) as high as it goes... 5th is also on highest setting. And in this config the trailer is already pretty nose up..

So I thought ok, my only options are smaller tires (sacrilidge !) or ?? I fitted a set of 265/65r18 and it added an inch but now the truck looks like a "train truck" (you know, with the skinny little train wheels).. super ghey... so want to go back to bigger tires but what else can I do ? Is removing the lift block a viable option? any other ideas ? I still need to be able to drive in ice/snow/mud when 5th isn't on for work.. so yeah... thanks.

ps no I cant put a hauler body on it I need the box for work...

-Ph
 
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#2 ·
I put 2" lowering shackles on mine. Needs air bags now though
 
#4 ·
Surprising that the flipped axles don't create enough height; I had to raise my Titanium 5th but did not want to flip axles - I went with the lippert correct track kit which raised it 2" giving me just under 6" of clearance. I had already increased the height of the trailer with larger lt tires a few years ago when I went away from trailer specific tires and was thinking of doing the dropped shackles but did not have to go that direction. These new ones are tall!!!
 
#5 ·
To get it to fit the '15 3500 SWB DBL CAB LB truck I already flipped axles, added 3" shackles off the frame, and dropped the pin, and raised the 5th hitch as high as it would go. On the new truck (same config crew cab), I didn't realize they came 2" higher ! I feel pretty lame. (doh) Its an older '09 so built when trux were small LoL.. aside from my FUGLY skinny train truck tires I really want another way forward..
 
#10 ·
Yes, all 2020/2021 HD's are the same height.

In the 1500 series, the gmc AT4 and the chev Custom Trailboss and LT Trailboss each have a 2 " factory lift.


Yes, the 20/21's HD's are taller than the previous generation.
And fwiw, the new HD's are taller than the 'factory lifted' 1500's.
 
#9 · (Edited)
ok so I took the wheels off etc. THERE IS NO LIFT BLOCK. what I read on forums as a lift block is actually just on the 1500 and on the HD theres no block its just a part of the spring mount and its integrated, definitely no block. so shackle is the only way ? has anyone done a small drop shackle on an HD 3500 ? any side effects ?
 
#11 ·
ok got it. so anyways, its a very real problem.

I have 5 trailers too (all for work) so I need to figure this out ! Was only honestly really worried about my big 5th but I'm gonna have clearance issues on the gnecks /w decks too...

Only option I am seeing right now is putting super lame 265/65-18s on and having er look like a "train truck" (you know, those ones that run the tracks with super skinny pizza cutter tires).. that would drop er an inch or so...

shackle ??
 
#32 ·
I ran into this when I went to the Reese Goosebox on our 5th wheel toy hauler. Pull with a 2015 Chevy 3500 Dually. The trailer to bed side was a little too narrow for my comfort. The Goosebox was set as high as was possible. Bought a gooseneck ball that was 1” taller for the Curt hitch. Doesn’t seem like much, but gave about 6” clearance total. Made pulling in and out of drives a lot easier on the dips.


Sent from my iPad using Tapatalk Pro
 
#15 ·
The lippert correct kit is for the trailer only and in my case raised my trailer approx. 2 inches, I didn't word that reply very good but I had also looked at the lowering shackles if I needed it and had asked others who may have installed those shackles and how it effected their trucks. None had reported any adverse affects from it but in the end I did not have to go that route.
 
#16 ·
Watching this thread ...

Coming from a 2004.5 Ram 3500, this new truck is 3" taller. My fifth wheel is already flipped. But,I thought I was going to have a bigger problem with it than I actually have. First, the squat from the trailer's pin weight was more than I thought it would be. That helped a bit. Second, I have an Andersen Ultimate Hitch which moves the kingpin back about 9". That reduces the amount of the trailer overhang that's actually over the bed of the truck. I have about 6" of bed clearance and the trailer rides just a bit nose up. I can live with it the way it is but would love to lower the truck a few inches to make it easier to get in/out and access stuff in the bed.
 
#17 ·
What 5th wheel hitch are you using?

We recently ordered a 5th wheel toy hauler to tow with our 2020 AT4 HD. I have the 6'9" bed.

The hitch I'm decided on is the B&W RVK3710, which is for the 2020+ puck systems. Now you have me concerned about height of the hitch and 5er to rail clearance.

I was looking at the Andersen Ultimate Hitch but have decided against it. My understanding for it though is that Andersen has released a new version that is slightly taller to accommodate the higher bedsides.
 
#21 ·
What 5th wheel hitch are you using?

We recently ordered a 5th wheel toy hauler to tow with our 2020 AT4 HD. I have the 6'9" bed.

The hitch I'm decided on is the B&W RVK3710, which is for the 2020+ puck systems. Now you have me concerned about height of the hitch and 5er to rail clearance.

I was looking at the Andersen Ultimate Hitch but have decided against it. My understanding for it though is that Andersen has released a new version that is slightly taller to accommodate the higher bedsides.
I have the same truck (even in the same color) and I have the hitch you listed. As explained in a previous post I had to raise my 5th whl to get the bed rail clearance that I wanted, I have towed into a boonedocking spot with no clearance problems and did a 1,400 mile round trip and it tows great. I had considered going with 1.5 inch lowering shackles before I raised it, I still wouldn't rule that out as in my estimation these trucks are too high as is. Once I hooked up my truck sits pretty level and I have between 5 and 6 inches bed clearance. Wished I had taken pictures when hooked up so that I could share them.
 
#18 ·
I have 2 hitches I've tried em both at max height, bed hitting doghouse when I do over the crown on my driveway... looking at lifting the trailer with lift blocks (!) cant really think of anything else I haven't done, short of lowering the truck which I really dont wanna do ..
 
#20 ·
I feel your pain. I'm new to 5th wheel towing, and trying to figure this stuff out makes my brain hurt! Our 5er that we ordered is already at 13'6". No option to raise it any taller without causing all sorts of clearance issues with overpasses, etc.
 
#19 ·
on the 2011 to 2015 ( not sure on newer trucks) , the 3500 when lowered causes interference with overload springs hitting the stops when driving unloaded. which is a real pain in the ass-literally and figuratively. I took the hangers out and added airbags to get cargo capacity back. looks better, fits my 5er without mods.
 
#25 ·
Thanks Tom! I've never pulled a 5er before, so I'll be spending some good quality time in an abandoned parking lot once we finally get it.

It's a Grand Designs Momentum G class. Approximate length is 39'10". We like to get out camping as much as possible and this will allow us to bring our RZR and our two golden retrievers will have a nice place to relax with A/C when we're out on the trail.

I'm anxious to use the truck for what it was made for.

Sorry to hijack your thread OP, I hope you come up with a good solution. Keep us posted please, it might be helpful down the road (no pun intended)!
 
#26 · (Edited)
So is it the AT4 option that's causing all the problem? When I traded my '12 for an '18 I noticed the newer truck sits really high, and it's just a regular HC.

I have to have my truck inspected to haul new RV's and the bedside is supposed to be 59" max. Mine was closer to 60" but it passed anyway. I really could do without all this extra height, especially on a highway truck. I understand extra clearance on an offroad package but not sure why they're making some of the other options so high now.
 
#30 ·
So is it the AT4 option that's causing all the problem? When I traded my '12 for an '18 I noticed the newer trucks sits really high, and it's just a regular HC.

I have to have my truck inspected to haul new RV's and the bedside is supposed to be 59" max. Mine was closer to 60" but it passed anyway. I really could do without all this extra height, especially on a highway truck. I understand extra clearance on an offroad package but not sure why they're making some of the other options so high now.
With the HD's the AT4 is the same height as the rest.

With the 1500's the AT4 has the 2" factory lift.

(even with the 2" factory lift, the 1500 is lower than the HD's...)
 
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#34 ·
Hi,

I just traded in my '15 SRW long box for a '21 AT4, am sooper stoked.. BUT:

on my new truck the bed rail to 5th wheel clearance is way too tight ! it was marginal on the previous truck and I didn't think it would be that different (doh). Now I cant take my 5th out of my driveway !! Trailer already had axles flipped already has the biggest tires it can on it it can fit and pin box is lowered (which raises the front) as high as it goes... 5th is also on highest setting. And in this config the trailer is already pretty nose up..

So I thought ok, my only options are smaller tires (sacrilidge !) or ?? I fitted a set of 265/65r18 and it added an inch but now the truck looks like a "train truck" (you know, with the skinny little train wheels).. super ghey... so want to go back to bigger tires but what else can I do ? Is removing the lift block a viable option? any other ideas ? I still need to be able to drive in ice/snow/mud when 5th isn't on for work.. so yeah... thanks.

ps no I cant put a hauler body on it I need the box for work...

-Ph
From my reading various RV fora for the past 15 years, with the newer trucks, they should have spacer blocks in the suspension you can remove to lower the truck. Not sure if it's still available, but you could add a Correct Track suspension alignment to your FW to gain 2" lift. Only other =safe= alternative is to add a spacer subframe on the FW, between the spring hangars and the frame. You can then raise the FW however much you want; just remember to stay at 13'6", or less. You'd want the subframe to extend at least a foot beyond the current front and rear spring hangar attachments and you'd also want to add cross-braces from side-to-side.

Lyle

Lyle
 
#37 ·
I thought the AT4s came with the pro tailgate and those tailgates are shorter than the regulars thus the bed rails are shorter on these? Also why would getting smaller tires or changing suspension height help clearance between trailer and truck bed rails? If you lower the suspension or tires of the truck 2 inches you are lowering the entire truck 2 inches. AKA the receiver where the trailer connects... Sorry if I missed something but I think you need to lift the receiver in the truck bed or extend the neck on the trailer. Do you have any pictures?
 
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