LBZ: ProThane Body Mounts

fajitatone

Almost Stock
Jul 6, 2007
733
14
18
WA
www.fajita.net
So I replaced the stock, worn, body mounts with ProThane mounts and did the GMT900 rear mounts. While the "Chevy Shake" at 40-45 MPH is gone, the noise in the cab is louder, but WOW the vibrations at idle. Especially when cold. I know that polyurethane is stiffer than rubber, but is there any way to quell the vibrations?
 

HWI

Member
Feb 7, 2016
36
0
6
FL
You are stuck with the vibrations with Prothane mounts. Go with some Dorman mounts or wait for the S&B mounts to come out. I replaced my rears with the GMT900 mounts as well, biding my time on the other ones until the S&B mounts are released.
 

gmduramax

Shits broke
Jun 12, 2008
4,045
226
63
Nor cal
So I replaced the stock, worn, body mounts with ProThane mounts and did the GMT900 rear mounts. While the "Chevy Shake" at 40-45 MPH is gone, the noise in the cab is louder, but WOW the vibrations at idle. Especially when cold. I know that polyurethane is stiffer than rubber, but is there any way to quell the vibrations?

Have your rotating assembly balanced :D
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,905
1,073
113
Neenah, Wisconsin
You are stuck with the vibrations with Prothane mounts. Go with some Dorman mounts or wait for the S&B mounts to come out. I replaced my rears with the GMT900 mounts as well, biding my time on the other ones until the S&B mounts are released.

Whats the details on the GMT900 rear mount, is there a quick "how to" that I should reference? My crew cab shakes like a MOFO inside above 40mph and it isn't driveline related, it's like a resonance.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,106
4,841
113
Phoenix Az
So I replaced the stock, worn, body mounts with ProThane mounts and did the GMT900 rear mounts. While the "Chevy Shake" at 40-45 MPH is gone, the noise in the cab is louder, but WOW the vibrations at idle. Especially when cold. I know that polyurethane is stiffer than rubber, but is there any way to quell the vibrations?

nope, the poly bushings put a ton of noise/vibration into the cab. i have a thread on here about when i did mine. I made it two days and fricken hated them.

i wound up putting dorman mounts in every mount and sold the poly's off. So far, they are holding up with 0 sag after 2 years.
 

N2BRK

Well-known member
Dec 31, 2009
1,898
211
63
Mine vibes more with Merchant driver's side engine mount and trans mount. My buddy's LMM too. I can't imagine all poly. Although, mine vibes a ton less than his - might be my Fluiddampr helping.
 

zakkb787

<that’s not me...
Sep 29, 2014
2,340
52
48
Granite Falls NC
You are stuck with the vibrations with Prothane mounts. Go with some Dorman mounts or wait for the S&B mounts to come out. I replaced my rears with the GMT900 mounts as well, biding my time on the other ones until the S&B mounts are released.

Saw a garage I follow post about putting the S&B mounts in a Ford and thought it was a typo till I looked. Pretty neat. Always nice to see new options for products from a trusted brand
 

fajitatone

Almost Stock
Jul 6, 2007
733
14
18
WA
www.fajita.net
You are stuck with the vibrations with Prothane mounts. Go with some Dorman mounts or wait for the S&B mounts to come out. I replaced my rears with the GMT900 mounts as well, biding my time on the other ones until the S&B mounts are released.

Any idea when this may be? I have to do engine mounts too. Should I do Merchant or somebody else?
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,302
1,596
113
Mid Michigan
IMO, using urethane for body mounts is foolish unless its a drag or pull truck only. Urethane has way too little "give", and you dont want that between body and frame. The ride quality will suck badly.
 

HWI

Member
Feb 7, 2016
36
0
6
FL
Whats the details on the GMT900 rear mount, is there a quick "how to" that I should reference? My crew cab shakes like a MOFO inside above 40mph and it isn't driveline related, it's like a resonance.
They are a straight replacement, no need to mod anything at all.

Any idea when this may be? I have to do engine mounts too. Should I do Merchant or somebody else?
No idea when they are coming out, I've been waiting for about 6 months now. On their website it just says coming soon.
For engine mounts I would just bolt the stock style, that will keep it from pulling apart and keep the vibrations to a minimum.