I NEED A 4.11 Differential

[Mike Hohnstein]

The 545 uses a much weaker torque converter structurally speaking, more over the
trans you have (MT 40/42) doesn't bear any more parasitic loss. In addition to
a stronger torque converter, the 40/42 converter has a clutch that positively
locks at speed. 545 has an open converter that slips all the time, not the tip
on the road due to heat generation and fuel consumption issues. The 40/42 has a
retarder range that is useful in slowing the vehicle both in traffic and on down
grades. 545 is great for school buses and vocational trucks, but changing to
one from your present transmission is a step back ward. You keep us up to date
with your gear selection and how that 391 does with it. I used to have a 391 in
my 31' Wanderlodge, they don't have the power to pull the gears you are talking
about, but hell, it's your dinero have at it. What you are overlooking is the
fact that the gearing you are considering will result in constant down shifting
on the highway and a lot detonation. (pinging)
Mike Hohnstein
Automatic Transmission Design Inc.
Germantown, WI
FC 35 diesel
FC 31 522" Big Block Chevy
450 hp @ 4200 585 lb.ft. @ 3000
----- Original Message -----
From: anglersoutreach
To: WanderlodgeForum@yahoogroups.com
Sent: Saturday, November 18, 2006 7:54 PM
Subject: [WanderlodgeForum] Re: I NEED A 4.11 Differential


Thanks for your replies.

The 4:11 will allow the 391 to run 60mph @ 2100rpm. Considerating the
stock 391 produces maxium torque at 2600-2800 rpm. I will be able to
run 70 mph @ 2450 rpm. A 4:56 may possibly be the better choice of gears.

I plan to change the camshaft, intake manifold, and make several other
modifications to the 391 that will enable it to run at these rpms
efficiently. These improvement will not decrease the dependability of
the 391. I am even considering replacing the Allison mt40 with a 545
to get rid of a lot of rotating weight.

Thanks, Billy





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