Installing a Trailboss 2" rear lift block on a non-trailboss truck

fondupot · January 11

Hi all, I installed the 2" block from a Trail Boss on my non-trail boss truck (2022 Custom). The part number I used was 84379975.

I was wondering if these blocks are tapered? I didn't think to measure them when I installed them, and now I am having second thoughts.

I can't seem to get an accurate measurement with them installed on the truck. As far as I can tell there wasn't any indication of a forward/backward indication on the block itself, which makes me think they are not tapered.

But I developed a very slight "rumble" coming from the rear of the truck after installing the blocks and I am not sure what it is. It's not that bad, but definitely noticeable. I also installed new Bilstein 5100's out back and have new Bilstein 5100's up front set on 1.5".

Any input is appreciated. Thanks

TrailBossMike · January 12

Have you had a 4 wheel alignment check?

fondupot · January 12

Truck was aligned after all the new bilsteins went in yes.

Diamond817 · January 12

So you added 1/2" more rake to your truck? 2" rear lift and 1.5" front lift?

The blocks are flat. The axle might be bound up a bit depending on the angle of the axle when the u-bolts were tightened. On a flat/level surface I would loosen all 4 U-bolts, bounce the rear of my truck with my body weight, then torque the U-bolts to 85lb-ft.

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Edited January 12 by Diamond817

fondupot · January 12

Yea, so the truck was pretty much level, before the lift, because I have a toolbox in the back with a bunch of stuff in it on a regular basis. But I wanted to get a little rake back. The rear lifted 2" with blocks, and I did 1.5" with the Bilsteins, because I read reports of them lifting more than what they were rated, so I didn't want to go too high. I ended up only getting about 1.25" up front, so I may have to do an adjustment and put the fronts on the 2" setting to bring it up a bit. Either way, the truck has about 1" of rake right now from rear to front. Not bad.

As for your recommendation, thanks. That seems logical. I can try that this weekend and see what it does.

Edited January 12 by fondupot

Vincej138 · January 12

3 hours ago, fondupot said:

Yea, so the truck was pretty much level, before the lift, because I have a toolbox in the back with a bunch of stuff in it on a regular basis. But I wanted to get a little rake back. The rear lifted 2" with blocks, and I did 1.5" with the Bilsteins, because I read reports of them lifting more than what they were rated, so I didn't want to go too high. I ended up only getting about 1.25" up front, so I may have to do an adjustment and put the fronts on the 2" setting to bring it up a bit. Either way, the truck has about 1" of rake right now from rear to front. Not bad.

As for your recommendation, thanks. That seems logical. I can try that this weekend and see what it does.

Your springs will settle also after a few days of driving. I think that's a bit of thing people see when they post higher #'s. Even on my 2.7L the 0" was a bit higher, then settled to be true.

Diamond817 · January 13

15 hours ago, fondupot said:

Yea, so the truck was pretty much level, before the lift, because I have a toolbox in the back with a bunch of stuff in it on a regular basis. But I wanted to get a little rake back. The rear lifted 2" with blocks, and I did 1.5" with the Bilsteins, because I read reports of them lifting more than what they were rated, so I didn't want to go too high. I ended up only getting about 1.25" up front, so I may have to do an adjustment and put the fronts on the 2" setting to bring it up a bit. Either way, the truck has about 1" of rake right now from rear to front. Not bad.

As for your recommendation, thanks. That seems logical. I can try that this weekend and see what it does.

Interesting. How much does that tool box weigh? I got exactly 1.5" of front lift from installing the Bilsteins. The weight of the tool box might be compressing the front end that 1/4".

fondupot · January 15

On 1/12/2024 at 11:14 AM, Diamond817 said:

So you added 1/2" more rake to your truck? 2" rear lift and 1.5" front lift?

The blocks are flat. The axle might be bound up a bit depending on the angle of the axle when the u-bolts were tightened. On a flat/level surface I would loosen all 4 U-bolts, bounce the rear of my truck with my body weight, then torque the U-bolts to 85lb-ft.

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So I did this over the weekend. Didn’t seem to make a difference. I didn’t loosen the shocks. But I loosened the u-bolts and then jumped up and down several times, til I was out of breath.

I wonder if my u-joints are worn and just aren’t happy with the additional 2” in them. The truck has 95,000 miles in it.

Did some highway driving today and it seems like the “rumble” is present at all speeds. It’s accompanied by a slight vibration that can be felt throughout the truck as well.

Any other thoughts?

Diamond817 · January 15

1 hour ago, fondupot said:

So I did this over the weekend. Didn’t seem to make a difference. I didn’t loosen the shocks. But I loosened the u-bolts and then jumped up and down several times, til I was out of breath.

I wonder if my u-joints are worn and just aren’t happy with the additional 2” in them. The truck has 95,000 miles in it.

Did some highway driving today and it seems like the “rumble” is present at all speeds. It’s accompanied by a slight vibration that can be felt throughout the truck as well.

Any other thoughts?

I would look at the U joints. How do the front hubs feel when you spin them? How about the CV axles?

fondupot · January 15

I popped under the truck to inspect the u-joints. I checked for play by hand, none apparent. The rear u-joint has some grayish dust/grease around it. Maybe that’s a sign it’s going bad. I should have taken a picture. I’ll go out there later again and get one.

Front CVs look fine. Front bearings appear fine. The noise feeling definitely feels like it’s coming from the “center” of the truck.

It was definitely paired to installing the blocks. I actually did the rear blocks and shocks about a week before I had a shop do the front struts. And I noticed the noise/vibration immediately on my test drive after doing the rear shocks and blocks.

Edited January 15 by fondupot

fondupot · January 16

Here are some photos of my u-joints. You can see the grayish dust/grease on the rear u-joint. Not as much on the front one, but a little.

REAR

FRONT

fondupot · January 18

@Diamond817 I ordered a pair of new u-joints. They’re supposed to come today. I’m gonna swap them in and see if that helps.

Naughty Donkey Performance · January 18

36 minutes ago, fondupot said:

@Diamond817 I ordered a pair of new u-joints. They’re supposed to come today. I’m gonna swap them in and see if that helps.

Please keep us posted as to what you find

fondupot · January 19

I got curious again today and went under the truck. This time I measured from the front of the spring perch to the center of the bolt on the front leaf spring bushing.

On my driver side I got 29.5”

On my passenger side I got 29.25”

Meaning it appears my axle is not straight. This is most likely the cause of my vibration/rumble. It has to be.

I am still going to replace the u-joints as a precaution, they should arrive today or tomorrow. But I am also going to loosen the u-bolts back up and straighten the axle back so it’s even on both sides of the leafs. Maybe the centering pin on the blocks has a large enough hole so that there is some play in getting them perfectly centered.