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  1. Vehicle Suspension
  2. Timbren
  3. Jounce-Style Springs
  4. Rear Axle Suspension Enhancement
  5. Extra Heavy Duty
Timbren Suspension Enhancement System - Severe Service - Rear Axle

Timbren Suspension Enhancement System - Severe Service - Rear Axle

Part Number: TGMRTT35D
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8,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader. Great Prices for the best vehicle suspension from Timbren. Timbren Suspension Enhancement System - Severe Service - Rear Axle part number TGMRTT35D can be ordered online at or call 1-800-940-8924 for expert service.
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Timbren Vehicle Suspension - TGMRTT35D

  • Jounce-Style Springs
  • Rear Axle Suspension Enhancement
  • Timbren
  • Extra Heavy Duty

8,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader.


  • Improves suspension, handling, and safety
    • Ideal for trucks with slide-in campers or an in-bed salt spreader
  • Provides additional support as needed, so you always get a smooth, comfortable ride
    • Allows the leaf spring ample movement and cushions light loads
    • Becomes more rigid as more weight is added
      • Increases stability - gives you great performance when you are hauling heavy loads
      • Reduces rear sag
  • Works independently - side to side
    • Helps to compensate for off-center loads
    • Reduces body roll when you have to swerve or execute a sharp turn
  • Acts as shock absorber, taking the brunt of bumps and rough roads
    • Extends the life of your suspension
  • Includes 2 Aeon hollow rubber springs, custom-fit brackets and hardware for simple installation
    • Replaces axle bump stops on frame
    • No drilling required


  • Capacity: 8,000 lbs
    • Do not exceed your vehicle's weight-carrying capacity
  • Designed to work with a suspension system that is in good working order
  • Limited lifetime warranty - satisfaction guaranteed

An example of sag on a vehicle's rear axle under a heavy load

Whether you're hauling heavy loads in your bed or cargo area or you're towing a trailer, you will often see the rear of your vehicle sag while the front end rises. In these cases, the rear axle is handling not only the weight of the cargo, but also more of the vehicle's weight. Because less weight is on the front axle, the front tires are making less contact with the road. Overall handling - traction, steering, and braking - is negatively affected. But the resistance from Timbren's Suspension Enhancement System works with your factory suspension to keep your vehicle level and improve your driving experience.

Diagram of the Timbren spring installed

The Timbren system comes with custom-fit brackets that are bolted onto each frame rail above the rear axle. Hollow rubber springs are bolted to the bottom of the bracket and hang down to where the bottom of the spring sits, 1" above the axle. The inch of clearance allows the existing factory suspension to operate normally under light loads and standard terrain, ensuring the smooth, comfortable ride that you are used to.

Animation of a standard Timbren rubber spring

Timbren Suspension Enhancement Systems are designed to work progressively. When the hollow rubber springs are compressed, the convoluted design causes them to quickly collapse along the folds. Once the folds are compacted, the stacked barrel shape increases resistance, stiffening the suspension and keeping your vehicle level.

Timbren suspension system works to prevent body roll

Each hollow rubber spring works independently to support the driver's side or passenger's side of your vehicle. This is helpful when you swerve or make sharp turns. Each spring is activated when it is needed, so body roll is greatly reduced. The independent action also works well when you are hauling off-center loads.

An example of a trailers swaying

Because the vehicle handles better with the springs, less turbulence will be passed along to the trailer, and this helps to keep the trailer in line. Your driving comfort is further enhanced if the trailer does begin to sway (from a gust of wind or a passing semi), because the movement from the trailer is not transferred to your vehicle. This also works to make the sway subside more quickly.

An empty truck on a bumpy road without Timbren

Another great feature of the rubber construction is that the springs absorb most of the road shock, creating a smoother, more stable ride overall. Wear and tear on the factory suspension is also lessened because the rubber springs work to prevent bottoming out on rough roads.

Timbren Suspension Enhancement Compared to the Competition

Timbren's Suspension Enhancement Systems are much easier to install than air springs - there are no air hoses to run, no compressors or gauges to hook up, and no manual adjustments to make. The rubber construction makes Timbren's springs more elastic than similar products constructed of microcellular urethane. And more elasticity allows for a more comfortable ride because the rubber has more travel.

GMRTT35D Timbren SES with Aeon Hollow Rubber Springs - Rear Axle - Severe Service

Installation Details TGMRTT35D Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Timbren Suspension Enhancement System - Severe Service - Rear Axle - TGMRTT35D

Average Customer Rating:  4.7 out of 5 stars   (6172 Customer Reviews)

8,000-lb Capacity hollow rubber springs sit above the rear axle to help stabilize and level your vehicle. Provides a comfortable ride by absorbing road shock and improving stability. Ideal for trucks with slide-in campers or an in-bed salt spreader.


after hooking up my 5th wheel camper, We went for test drive, they changed the ride to rock solid and ruined it, I returned to the and removed them, Big mistake on buying them I'm ordering Air Bags like I should have in the first place


After a year of ownership and towing my toy hauler many times, I’m happy I went with Timbrens as opposed to air bags. Easy install, maintenance free, and they really do help keep things level.


Removed air lift bags and installed Tim bren

Ram 3500

Added these bump stops to my GMC Denali 3500 to help improve towing my fifth wheel. They do a great job of preventing the bed from sagging under heavy load. The truck is perfectly level with 3000+ pin weight on the hitch. The truck is extremely stable when the load is sitting on these rather than just on the springs. They do limit travel of the rear suspension (which is exactly what they're designed to do) when not under load. So with no load on, some big dips or bumps that would normally be absorbed by the suspension travel cause the suspension to hit the bump stops instead. It's well worth the tradeoff though for the added payload capacity.


These are a must have for a slide in camper. I am one my third truck and these are my third set.



These things are bullet proof! Air bags are for old people who never leave the pavement.


They work as described,happy with the purchase & installation was a breeze


I’ve had Timbrens in the front of my last two trucks for plowing and I have been more than pleased. The truck rides just as well. I decided to get a set for the rear of my 2020 Silverado 2500HD to help with my gooseneck equipment trailer and truck camper. Installation was a breeze, maybe 10 minutes for both sides. I highly recommend them, and I highly recommend etrailer.

2022 GMC Sierra 3500

After 1 year hauling a 16K fifth wheel up and down the east coast, the Timbrens are working great. Smoother ride, no sag. Mechanic installed them in 15 minutes.


Items were exactly what I needed, description was spot on. Super fast delivery.


Waiting to see how they do with my 5th wheel rv. Easiest install I've ever done.

2022 GMC Sierra 2500

Very easy install. Didn’t want airbags. This is perfect for towing my 4 horse gooseneck trailer.


Extremely "easy" to install. Took me almost longer to get my jack, some boards together and soap than it did to install this product. Shipment came quicker than I paid for it to come. Wow! Very pleased with Samantha's customer service!


These are my third set of Timbrens on the third truck in a row. I installed them in about 45 minutes by myself in 105 degree Texas heat.

2019 Chevrolet Silverado

Easy installation 2019 Silverado Hight Country 3500 4x4 single axel, if you can lift the rear of your truck as we do. The only thing is when the truck is under no load and we drive it the rear suspension will bottom out and kit the suspension enhancement system when we hit a pump on the road. Its sudden and it can be felt by the crew in the truck. Under load they work great.


I've been using these for a month now. I decided to give these a try instead of air bags. So far I've been please, Yesterday I had 2,500 of tongue weight (I have a scale on my hitch, it's super handy btw) on my 2021 2500HD and it handles very well. These didn't allow the truck to sag, so the truck bed was fairly close to level (so a very slight sag). But without these, my front end would've looked like it was way higher then the front. So far, I'm a believer in this product, 10 minute install and your set


arrived fast and was easy to install


Work great. Offer stability, especially in corners. Do not provide for a level truck as the weight of the camper still compresses the springs up to where the Timbrens engage, but I knew that going in. Alternative to full-on air leveling systems.


Got excellent coaching on the proper part for my 2020 GMC 2500 HD. The new horse trailer did not exceed the the weight limits, but squatted the back end more than I wanted. These new bump stops worked perfectly. Install was easy, and the truck rides like normal without load and rides better with load, so its a win win. Thanks for the quick shipping, follow up, and always having great reviews to read when selecting parts to purchase. THANK YOU ALL at "etrailer"...


etrailer never disappoints. Installation was easy, did not have to raise truck axle per directions. A small amount of bearing grease worked better than the recommended soapy water. Cannot comment on effectiveness yet as I am still awaiting delivery of our new truck camper...more to follow.

2015 Ram 3500

Arrived fast and installed in about an 30 minutes.

Removed the old bump stops with couple screwdrivers.

For the new install, don't waste your time with soapy water (I tried it)...just use liquid soap without the water...worked way better. Coat the entire top and 1/4 inch down the side to the first indent.

I used a flat 15 inch pry bar to help push them in. I then jacked the truck up and put a piece of wood between the stop and the axle and lowered it. Helped seat them fully.

Installed on a 2021 Chevy 3500 4x4 dually.

2014 Chevrolet Silverado 2500

Etrailer provided me excellent service. One of my Timbren bump stops was lost due to my fault. I needed another set very quickly. They made sure they were shipped promptly and followed through to make sure that I had them in time. Excellent customer service, and unlike amazon I was able to speak to real people who cared.


Works great

2021 GMC Sierra 3500

I have purchased a lot of things from etrailer and they never disappoint. The products are always as they say they are and the shipping is above average; meaning most of the time is before the quoted time of delivery. The Timbrens went right on no problems. Thank you etrailer!


Great product! Sold on it after hitching up the first time. Mrs Hally took care of my order and got it to me the next day. Was a great experience with the etrailer & timbren products. Will order from again. Thanks.

2011 Ram 2500

Adds just the right additional support for the heavier fifth wheel as the truck approaches it's maximum load. 2500 HD Duramax. Simple instructions and easy to install.

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