Axle Ratios for the M1028 & M1031: Same or Different?

[donald_r]

I picked up a stock, low mileage M1031 Contact Service Body truck this month.

The first thing I noticed is while driving at 55 mph the engine seems to be screaming.

The 1028a1 is supposed to have the same axle ratios, yet my stock 1028a1 unit can go 60 mph, even 65 for a short burst without the same screaming engine noises.

I spoke with Alex over at IdahoMotorPool.com, about this issue, and he said he also noticed this issue with all the ones he has received and sold over the years. He thought the axle ratios were NOT the same for the two vehicles.


My questions are:

What do you guys know about this issue?

Have you experienced it?

Are the ratios different for the two vehicles, and if so, is it documented somewhere?

Don
Boise, Id.

 

[Westech]

yes there the same. 4.56 the Trucks ALL had 4.56..... the blazers ALL had 3.08.

 

[donald_r]

Then maybe its the transmission gearing that is different. Something sure is.

 

[Westech]

no all TH400's are the same 3rd gear... 1:1

 

[merace19]

Look to see what size tires are on it. If smaller than the stock ones then your RPM will be higher. I have run 37s and that is a little to big for the diesel. But a 33-35 seems about right to me.

 

[Recovry4x4]

I'd be checking for a loose air filter housing. When these get loose they sound like they are sucking the hood in.