Well I went to a few "big rig" shops on Friday wanting to get one of the free flow Donaldson or Nelsons. Only one shop had a Donaldson in stock and it was 5" in and out and they didn't have any reducers to be able to match them up. I would like only to replace the muffler. One shop told me they could order it but would need the dimensions I want to stay with 4" . Hoping someone here had that handy so I order it. Still want to know if I can go with duals after the replacement. If so how and what is needed?

 

If you look at Donaldsons website you will find a wide range of mufflers that would work on our trucks. Here's a couple

M100464 for the 4" Id Od 51" long muffler

Exhaust Mufflers Product Attributes
A - Inlet Diameter (Inches): 4
B - Body Diameter (Inches): 10.33
D - Overall Length (Inches): 51
E - Outlet Diameter (Inches): 4
Rated Flow LR (CFM): 820
Rated Flow MR (CFM): 1159
Rated Flow HR (CFM): 1420
Back Press LR (In Hg): 1
Back Press MR (In Hg): 2
Back Press HR (In Hg): 3
Attenuation (dBA): 25-35
Product Type Description: Muffler, Round, Style 1,
Product Type Description 2: Wrapped
Primary Application: SVV, 6-71N, PRE''78 NOISE



Packaged Dimensions
Country of Origin US
Gross Height in Inches 10.5
Gross Length in Inches 52
Drawing Version U
Gross Weight in Pounds 49.8
Pieces Per Pallet 12
Gross Width in Inches 10.5


M085171 for 4" 40" long muffler.

Exhaust Mufflers Product AttributesA - Inlet Diameter (Inches): 4B - Body Diameter (Inches): 8.5D - Overall Length (Inches): 40E - Outlet Diameter (Inches): 4Rated Flow LR (CFM): 1800Rated Flow MR (CFM): 2546Rated Flow HR (CFM): 3119Back Press LR (In Hg): 1Back Press MR (In Hg): 2Back Press HR (In Hg): 3Attenuation (dBA): 8-12Product Type Description: Muffler, Round, Style 1Primary Application: OFF ROAD APPLICATIONS
Packaged DimensionsCountry of Origin USGross Height in Inches 8Gross Length in Inches 41Drawing Version UGross Weight in Pounds 18.85Pieces Per Pallet 30Gross Width in Inches 8