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2003 GMC Sierra
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Timbren

Timbren Suspension Enhancement System - Rear Axle

Part Number: TFRTR350HD
7276 Reviews | 4 Questions
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$398.07
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2003 GMC Sierra

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8,600-lb Capacity. These hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Becomes more rigid as more weight is added for great performance when you're hauling a heavy load. Great Prices for the best vehicle suspension from Timbren. Timbren Suspension Enhancement System - Rear Axle part number TFRTR350HD can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Timbren Vehicle Suspension - TFRTR350HD

Highlights

  • Custom Fit for Your Vehicle: Mounts to existing attachment points
  • 8,600-lb Load Support: Keeps your vehicle level and stable when hauling or towing heavy weight.
  • Safer Steering and Braking: Prevents rear sag so handling stays steady and braking feels consistent.
  • Reduces Body Roll and Sway: Independent rubber springs keep control when turning or hauling uneven loads.
  • Smoother Ride on Rough Roads: Rubber springs absorb bumps and prevent bottoming out under load.
  • No-Drill DIY Install: Bolts to the frame with included brackets and hardware for quick setup.

Features to know about

Stay Level and Confident Under Heavy Loads: 8,600-lb Rear Suspension Support

When the rear end squats under heavy weight, steering and braking can feel off. The Timbren Suspension Enhancement System adds up to 8,600 lbs of load-leveling capacity to keep your vehicle level and steady when hauling or towing. These hollow rubber springs stiffen progressively as more weight is added, improving stability and keeping your factory suspension from bottoming out. The result is confident handling and a level stance even when you’re carrying serious weight.

Truck with rear sag under heavy load demonstrating need for Timbren suspension enhancement system

Reduce Sway and Body Roll: Independent Spring Action

Heavy loads or top-heavy setups can make cornering and crosswinds feel unpredictable. Each Timbren spring works independently to support its side of the vehicle, cutting down on body roll and sway when turning, swerving, or hauling off-center loads. With the springs taking the weight as needed, your ride feels planted through curves while helping trailers stay in line behind you.

Illustration showing Timbren suspension reducing body roll, sway, and squat during turns or uneven loading

Illustration of truck towing trailer experiencing reduced sway with Timbren suspension enhancement system

Smooth Out Rough Roads: Rubber Springs That Absorb Shock

Bumps, dips, and uneven roads are easier to handle with Timbren’s hollow rubber springs taking the hit. Acting like shock absorbers, they cushion impacts and absorb road shock before it reaches the cab. This keeps your ride smoother when loaded and helps protect your suspension from wear by preventing bottoming out on rough surfaces.

Empty truck driving on rough road illustrating Timbren suspension shock absorption performance

Simple Bolt-On Upgrade: No Air Lines or Adjustments Needed

Installing extra load support doesn’t have to be complicated. The Timbren system bolts directly onto the frame above the rear axle using custom-fit brackets and included hardware—no drilling or air hoses required. Once installed, the springs automatically engage under load and return to normal clearance when unloaded, giving you a smooth everyday ride without gauges or manual adjustments.

Specs

Weight and Capacity

  • Load-leveling capacity: 8,600 lbs

Note

Timbren springs will not increase your vehicle's weight-carrying capacity. Do not exceed the manufacturer's recommended weight limit.

Diagram showing Timbren suspension spring installed above vehicle rear axle in loaded and unloaded positions

Warranty

  • Lifetime warranty
  • Satisfaction guarantee

FRTR350HD Timbren SES with Aeon Hollow Rubber Springs - Rear Axle

Installation Details TFRTR350HD Installation instructions

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Video of Timbren Suspension Enhancement System - Rear Axle
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Feature Breakdown: Timbren Suspension Enhancement System-TFRTR350HD

Today. We are taking a look at the Timbren Rear Axle Suspension Enhancement Kit for your Ford Transit. Before we dive in, let's see if the suspension enhancement system is gonna be a great option for your Ford Transit. Suspension upgrade Why Adding weight, more weight, and even more weight causes rear sagging, your headlights will point up, you will get worse handling and steering, less control and less comfort. With suspension enhancement added, your ride stabilizes, it levels out your vehicle, better control and steering, headlights straighten out, reduces road shock and have a safer ride in comfort. Check out the footage that we took underneath of your Transit.

We put about 250 pounds on a cargo carrier, and as you can see, the factory bounce stops don't even hit the axle. So it does feel pretty violent in the cab. Once we have the new bounce stops installed, you notice there's a lot smaller gap between our axle and the bottom of the bounce stop. It definitely helped a lot on the test scores, so the whole entire back suspension engaged much quicker. And also the biggest improvement I saw was when we took these big wide turns and really sharp turns at a higher speed.

I didn't feel the body of the vehicle roll near as much. The bracket on top is gonna be made of steel and it has a powder coated finished, so it's not gonna really rust away over time and the bounce stop is gonna be made of rubber. But it is a hollow rubber, so it's not just gonna completely stop your axle. It's also gonna flex, even with those heavier loads you may have. If we do have a really heavy load on here and it does hit the axle, it's gonna be a lot more heavy duty than the factory bounce stop that we removed earlier.

This is not gonna increase our Transit's capacity when we're hauling, it's just going to handle those heavier loads a little bit better. So the leveling capacity of this is gonna be 8,600 pounds. It goes in the same exact spot as our factory bounce stop. All you need is a socket, maybe an extension or two, a ratchet to tighten it down. It's a very quick and easy process, so let's show you how.

First you wanna chock your front wheels. Then we want to jack up the back of our vehicle. The goal here is to get the suspension on the rear axle to sag, so we have a little bit more room to work with. And then find a solid part on your frame to put your Jack stand. Let's remove the factory hardware. All we gotta do is just pull this out like this and undo this bolt. Take a 13 millimeter socket to loosen and remove this bolt. Here's our factory hardware. So there's two different options we have with our new system. One, we can just have the metal plate here and the main bounce stop with a smaller bolt. That's a little bit bigger than the factory set up. Or we can go ahead and use this extra spacer that's included with the longer bolt to make it a little bit taller. The goal here is we want at least a half an inch to a inch and a half a gap between the bottom of this and our axle. Some usual measurements to see which one's gonna be best. This one has a height of seven and a quarter inches. And this one without the spacer has a height of six and a quarter inches. What we're doing is not using the spacers. So we're using the smaller bolt and then you want the rounded part like this to be facing up towards your frame. You definitely want to use a short socket and it's gonna be a 17 millimeter. That's just going to make sure it's not gonna fall down into the socket too much, cause we do need to catch some of these threads. Lift it up into place, line it on up and thread it down. And then we can go ahead and tighten this down all the way once it's in place. Quick little tip, one, use a shallow socket, two, if the bolt kind of falls in, even if it's just a half inch, you are gonna want to put something in there just to keep that bolt pushed up in the outside of the socket right here. So the threads are gonna be able to touch the threads on the frame. Now repeat on the other side, we can take our jack's out and we can lower our Transit down and remove the chocks. Doesn't take a whole lot of time to enhance the suspension on your Ford Transit. And that's pretty much it for a look at the Timbren Rear Axle Suspension Enhancement Kit..

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Ratings & Reviews

4.7

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8,600-lb Capacity. These hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Becomes more rigid as more weight is added for great performance when you're hauling a heavy load.

by:

Stiffens and corrects kneel in rear end of 2023 Chevy Silverado 1500. You will notice a stiffening of the rear end suspension while unloaded, but it’s a fair trade off to prevent sagging and porpoising while towing. I found it easier to pull the rear wheels and work from the side than underneath the vehicle while installing.

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The timbres bump stop is exactly the right height to meet the axel when the trailer is connected with all its weight onto the hitch. I have an Andersen weight distribution hitch and it levels out perfectly. The day picture is with the coach (Winn 2100bh) with factory equipment. The night picture is after the timbres are in place. Looks good.

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It has been almost a year since I installed Timbren Suspension Enhancement Systems (DVF350 and DVR350R) on the front and rear of my 2003 Dodge RAM Van 3500. These bumpers replaced the OEM bump stops that were on my van. I like the Timbren bumpers much better than the OEM bump stops because they provide a progressively cushioned response for suspension compression when traveling over significant humps like speed bumps in a parking lot, or curb ramps into driveways. I did not like the abrupt stop the OEM bump stops provided when traveling over the same objects. I installed the Timbren rear bumpers first, and after a few months of use, I decided to add them to the front. In both cases, the front and rear Timbren bumpers were easy to install once the OEM bump stops were removed. Installation required reuse of the factory hardware. On my van, the Timbren bumpers are not always engaged. Under normal load and travel conditions the bumpers are relaxed and about 1/2” away from the suspension landing points. However, their presence is much appreciated and very noticeable when the van is carrying heavy loads or handling significant humps.

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Absolutely Pleased with the TIMBRENS. They were easy to install, and took less than an hour to install both. I noticed a slight stiffness in the ride as the rear bounced over a bad roadway. Towing is great, with a nice level and smooth ride. I am glad that I did not order the heavier duty Timbrens, than what was recomended for my truck. I believe the ride would have been too stiff. If you look at the photos showing the timbrens, the truck is still lifted in the rear, so what you see is a big gap between the rubber, and the steal plate. When the truck is lowered, there's 1" of space as it should be. BTW, I have been purchasing from etrailer for years now, and I have to say that I have never had any issues with any orders. They are my go to folks for all of my vehicle suppension stuff and trailer stuff. You can't go wrong with buying from them.

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Just got these on and haven’t been able to do a lot of testing yet, but it looks like they command their price. Huge difference in sag in the rear end of our Honda Pilot. As others have appeared to do in this review section before me, I started using a WDH with these and that looks to really be the winning combination with the Timbren SES. Our travel trailer is 3,500 lbs and it was squatting the pilot pretty well before. This timbren SES is a great addition. Can’t go wrong.

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My F53 was like driving a waterbed down the road. With the Timbrens, it’s a different vehicle. Should have installed them years ago. Etrailer is my go to for anything trailer. FAST shipping and prompt responses to questions or concerns.

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2022 F250 Super Duty. Super easy to install. I have about 3/4" gap between the spring and the plate. Time will tell how they impact the ride quality and how much sag they mitigate with my 5th wheel hooked up.

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by:

Timbren Spring Helpers were exactly what I needed on my Tundra plus a spacer kit since I have a 3” TRD lift. They were packaged neatly, with proper hardware, and excellent instructions! They absolutely do exactly what they are supposed to do! Truck rides much better and helps level out the load!

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by:

I'm suitably impressed with the difference i feel.
I have about 250 lbs. of static load with my topper and Decked cargo system. This put my install gap with no spacers just under the reccomended 1 inch minimum.Then add a couple hundred more pounds hauling music gear 100 shows a year, and the stop is resting on the axle.
I feel the absorption of the Timbren material is better than the flimsy stock bump stops. More cushion.
Where i really feel the difference is in the stabilty of excessive side sway when turning while loaded.
I have a gig coming up that will involve some unpaved mountain roads to get there so I think i will have a real goid idea of how these Timbren's will perform.
Instalation took me about an hour at 11 p.m.
The product it of the highest quality in design and build.
And Etrailer is a company that I would not hesitate to buy from in the future.
Thanks Dee Dee.
You rawk!!

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looks great



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Good product worked well and a nice company to deal with I will deal with them again . Thank You



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helped



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Good product



by:

They definitely reduced sway and lean when driving. But also seems like you really feel every bump and increase road noise?
I assume since vibration from axle can now travel directly to frame?
Might need to upgrade shocks?
Might soften liitle over time?
Might need to get softer onesv
Only have gone 80 miles with them so far.
Will give it another few hundred miles and see what feel then.

Overall pretty happy So far.

2017 Thor Gemini TX



by:

Install was easy. Raised our Thor Gemini up as product said it would. Great job etrailer!



by:

Good, very Good, no problems, better as air ride!



by:

They are awesome took the sag out of my van also lifted it about 2 inches so I don’t drag bottom when pulling in and out of my driveway .
I installed them quickly and easily!



by:

Excellent customer service!



by:

We purchased these for our one ton Ford Transit, which was converted by Winnebago into an RV. The springs did stabilize our ride and take away most of the vehicle roll. However, they also made the ride more bumpy. It's a trade off if you're looking for a solution to your RV riding conditions.



by:

I LOVE my Timbrens on both of my F350’s, Ranger & Transit 350
A+
I’m no fan of leaking air bags

Brooke M. profile picture
Etrailer Expert

Brooke M.

4/1/2025

I agree with you there! There's something to be said about a product with no maintenance. Out of curiosity, because Timbrens seem to be pretty polarizing, do you use these on work trucks/vans?



by:

I am very pleased with these pillows, they are better than inflatable pillows and all my friends who have a Ford Transit, on my recommendation, bought and installed them on their cars and are very satisfied!

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by:

Initial feels: Definitely made my Motorhome steering more responsive, did firm up the rear a bit. Make sure to check the size of the hex on the bolts I had 1-17mm and 1-16mm

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25
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See what our Experts say about this Timbren Vehicle Suspension

Do you have a question about this Vehicle Suspension?
  • Best Timbren Kit for a 2019 Ford Transit T350 Motorhome Chassis
    The best Timbren kit for your 2019 Ford Transit T350 motorhome chassis is part # TFRTR350 rated for 5,600 lbs. The other kit # TFRTR350HD you referenced is rated for 8,600 lbs and designed around vehicles with heavy-duty applications like a service vehicle. The standard kit will give you the best ride quality which is why I recommend going that route. If you were to use the heavier rated kit then the ride quality would be very harsh and you wouldn't enjoy driving your motorhome around.
    view full answer...
  • Recommended Suspension Support to Address Sway on a 2020 Leisure Travel Wonder Motorhome
    Hey Anker. I recommend starting with the Timbren Suspension Enhancement System item # TFRTR350HD and seeing how that addresses the sway you're feeling on your 2020 Leisure Travel Wonder Motorhome. If you had a top overhang I would say tackle the front and the rear end at the same time. The Timbrens are going to prop up any squatting you're encountering and help with any top heavy feeling you're getting when you make turns. We don't have a set of Timbrens for the front end of your 2020...
    view full answer...
  • Timbren Suspension Enhancement For A 2024 Ford Transit 350 HD High Roof Passenger Van
    Hello Ronald. It sounds like you are on the right track here because the Timbren Suspension Enhancement System - Rear Axle Item # TFRTR350HD is going to be the best choice for your 2024 Ford Transit 350 HD High Roof Passenger Van. These are rated for 8,600 lbs which is considered heavy-duty and is recommended especially for dually high roof models.
    view full answer...
  • Rear Suspension Enhancement Option for a 2017 Ford Transit T350 Dually
    I do have a rear suspension enhancement option that will work with your 2017 Ford Transit T350 but as you mentioned, the Air Lift LoadLifter 5000 Air Helper Springs part # AL57213 will not work on models equipped with dual rear wheels. For a similar type of suspension enhancement that will fit your T350 with dual rear wheels, I recommend using the Timbren Suspension Enhancement System part # TFRTR350HD. The Timbren Suspension Enhancement System will act as a buffer between your frame and...
    view full answer...

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Info for this part was:

Employee Leah B
Edited by:
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