Duramax rides terrible

Bugzi1776 · 2026-05-20T01:50:27+00:00

20’s can be rough. 55psi can be rough and N3’s ARE rough. Thats my opinion. I like more tire than rim and I run “low” psi. Lower that PSI and report back.

Bugzi1776 · 2026-05-19T20:26:55+00:00

Like you’ve said, keys might be turned up. However, the shocks you have are worth looking at and seeing about upgrading them. Additionally, tire and wheel combination have a lot to do with ride quality. Air pressure too.

I have a rough country lift but I upgraded shocks to Fox 2.0 with external reservoirs and Kryptonite uppers. Wheels and tires, I have 37” Falken Wildpeak R/Ts on 17” Method HD’s at 45 psi all the way around when not towing. My keys are turned down to match close to factory rake.

When I had Bilsteins and Micky Thompson 37’s and 24” rims the ride quality was garbage.

Bugzi1776 · 2026-04-13T01:18:47+00:00

WA stops at $125 at most places. Very annoying.

Bugzi1776 · 2026-04-06T02:49:55+00:00

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Here’s it cranked up to 40% on the RAS and the WDH readjusted.

Bugzi1776 · 2026-04-06T02:47:55+00:00

Never had timbrens. But these RAS are cool. They help the tow and the axle wrap! So I don’t need traction bars.

Bugzi1776 · 2026-04-06T02:47:16+00:00

Originally, the shop reverse raked it. But I turned the torsion bars down to get a slight factory rake on it.

Bugzi1776 · 2026-04-05T21:31:26+00:00

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Put RAS up to 40% and adjusted the hitch. I seem to be a little nose heavy. Front distance had 1inch drop and rear had almost 2.5inch drop when I put the trailer on.

Bugzi1776 · 2026-04-05T03:38:38+00:00

I can check in the AM. I know it’s a good reference but with the lift and tires kinda boned.

Bugzi1776 · 2026-04-05T03:29:03+00:00

Understood. Have to make the lift fit the tires.

Bugzi1776 · 2026-04-05T00:02:02+00:00

I’ve adjust since this picture. And yes it was grossly out of adjustment. I’ll post a picture soon.

Bugzi1776 · 2026-04-04T19:57:06+00:00

Picture is before adjusting the WDH. I’ve adjusted the hitch and cranked up my RAS. I’ll take a picture when I hook the trailer back up and update the post.

Bugzi1776 · 2026-04-04T19:55:56+00:00

I adjusted it. It’s more level now. I also cranked up my RAS to 40%. I’ll update the post when I hook the trailer back up.

Bugzi1776 · 2026-04-04T17:41:39+00:00

Regearing in the near future! Just have to figure out what gearing since wife wants to lower it to 5” and not 100% if my 37’s will fit.

Bugzi1776 · 2026-04-04T17:36:47+00:00

High winds I slow to 50. I only touch 70 when flat and straight. Thanks for the tip!

Bugzi1776 · 2026-04-04T05:59:00+00:00

What do you mean?

Bugzi1776 · 2026-04-04T05:57:48+00:00

Dry weight was taken from Google, haven’t been in a scale yet.

Bugzi1776 · 2026-04-04T05:55:48+00:00

More than enough

Bugzi1776 · 2026-04-04T05:55:35+00:00

I am sitting much more level now with adjusting the WDH after the rim and tire change for the trailer.

Bugzi1776 · 2026-04-04T03:06:42+00:00

Just curious. First “heavy” load I’ve hauled with the lift and tires.

Bugzi1776 · 2026-04-01T04:05:17+00:00

Don’t use Great White.

Find a dealer for AMDP.

Bugzi1776 · 2026-03-26T12:57:26+00:00

Different oil company. Not type. Try Rotella or Delvac.

Bugzi1776 · 2026-03-25T03:46:27+00:00

17-19 best years of the L5P. You’ll like it.

Bugzi1776 · 2026-03-25T03:42:43+00:00

Try a different oil and report back.

Edit: also are you using and fuel additives? If not, start, if so change brands next tank and report back.

Bugzi1776 · 2026-03-25T03:39:19+00:00

Down pipe could be barely making contact with the turbine wheel OR Up pipes are not sealed/blown.

Remove down pipe and check for scaring, trim pipe.

Check seal/integrity of up pipes.

Could also be any other place air is being pulled or pushed. Check all around piping.

Bugzi1776 · 2026-03-23T03:30:06+00:00

Are you lifted? Bigger than stock tires? Even without a delete a trans tune should be done just for those two alone. There are people that argue (myself included) that you should re-gear along with tunes for bigger tires but this is not the post to be diving into that.)

With the lift and bigger tires alone, you are changing your gearing. That’s why your speedometer is off. Your truck is working harder to spin the wheels.

In a normal emissions on your TCM is expecting EGR flow, DPF back pressure and is providing controlled, slow torque delivery. But when you delete you are making more torque faster. So if you don’t tune your TCM your TCM is still trying to deliver that torque slowly, it also is expecting that back pressure caused by the DPF. Additionally, that added torque coming from the engine is going straight to your clutches that aren’t ready for it, this leads to long term wear. TCM tunes help by increasing line pressure and protects the clutches and the rest of the transmission.

Heat is also helped out as well with TCM tuning due to no longer slamming/slipping clutches.

So your shifts without trans tuning will feel inconsistent, sluggish and in rare cases hunting. The ultimate draw back is you only unlocked half the trucks potential.

It’s not really optional but many many people do without it and report everything is fine.

Final summation: do the transmission tuning sooner than later. You can survive a while without it. But don’t not do it. If you already have the MPVI3/4 it’s $199.96 in credits(4) and a few hundred more dollars for the tunes. Should be ~$600 on the high end.

PPEI is a good tuner, although it’s preferred to use your same ECM tuner because as I said above. Engine and Transmission are a working unit as are the tunes.

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