I NEED A 4.11 Differential

[anglersoutreach]

I have a 1970 Wanderlodge with a 391 Ford and MT40 Allison. The Bird
has a 5.8 differential now and runs 60 mph @ 3000 rpm's.

I would like to replace the 5.8 with a 4:11.

Does anyone know a source where I might find one?

Thnaks, Billy

[davidkerryedwards]

Isn't 5.8 to 4.11 an awful big leap? Even the lower powered CAT engines run
lower gears
than 4.11.

Kerry
82 FC 35
Denver

--- In WanderlodgeForum@yahoogroups.com, "anglersoutreach"
wrote:
>
> I have a 1970 Wanderlodge with a 391 Ford and MT40 Allison. The Bird
> has a 5.8 differential now and runs 60 mph @ 3000 rpm's.
>
> I would like to replace the 5.8 with a 4:11.
>
> Does anyone know a source where I might find one?
>
> Thnaks, Billy
>

[Mike Hohnstein]

Don't do that, you will be sorry. I have the same chassis as you, repowered
with a custom 520 cu.in. engine that dynoed 450 hp. My rig weighs 20,000 lbs.
and has the 5.8 rear gear
and a 42" dia. tire. I see about 60 at 3000 rpm. I could get by with less
reduction, a 5.2 would be good in my case.
However I was unsuccessful in finding any support for the axle in my coach due
to it's age. My recommendation for your old Ford engine would be 5.5 or maybe
the 5.2. The engine doesn't have the nuts to pull more gear than that. Lugging
the 391 isn't wise.
MH
----- Original Message -----
From: anglersoutreach
To: WanderlodgeForum@yahoogroups.com
Sent: Wednesday, November 15, 2006 9:41 AM
Subject: [WanderlodgeForum] I NEED A 4.11 Differential


I have a 1970 Wanderlodge with a 391 Ford and MT40 Allison. The Bird
has a 5.8 differential now and runs 60 mph @ 3000 rpm's.

I would like to replace the 5.8 with a 4:11.

Does anyone know a source where I might find one?

Thnaks, Billy





[Non-text portions of this message have been removed]

[anglersoutreach]

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

[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





[Non-text portions of this message have been removed]

[anglersoutreach]

Thanks Mike, you convinced me to stay with the mt40. Did your 31' come
with the Chevy or did you convert it? I worked for GM for about 20 yrs
as a technician and would really like ot go to a Chevy instead of
spending money on the 391.

Thanks, Billy

[Mike Hohnstein]

A fellow gave me 643 Allison that had been in a dump truck with a 427 truck
engine. The adapter parts worked for the 40/42 but I had to take some material
off the fly wheel to get the pull up clearance right. I had my local machine
shop balance the flywheel for a 454. Had to screw a counterweight in the right
place, you know how that is. I had a whole truck to get parts from, it was a 85
C 70, got the stainless headers and all the stuff that made the installation
pretty easy. A 454 with the 6 speed trans works real well. If you have air
brakes you will crafting to get the pump mounted. I do have the stuff to mount
air brake compressor on a big block Chevy. My 31 has juice brakes and I had to
replace all the cylinders, lines and hoses. I decided to use the dot 5 silicone
fluid, expensive but it doesn't attract water the way conventional fluid does
and it doesn't hurt paint.
Problem with the old Ford is parts are made out of unobtainium, not available at
any price. And what you find you wouldn't want to use. The 454 fits great in
the chassis and has plenty of power for a 31. The radiator is big enough for
the Chevy and the GM steering pump is better than the Ford parts. I had to
craft a Ford Louisville steering box to mine as it had the old lame ram on the
cross link type of power steering.
I had a 454 boner motor in the 31 to shake it down but soon installed the
stroker 522. That makes the 31 run. If you could find a tired 540 race motor
short block, you could create a great power plant, using flat top pistons and
oval port heads. I used the truck holley intake and it works fine.
HEI ignition and a 800 Holley. With a big engine you could try to find ratios
in the high 4s. I have not been able to find any gears for the diff in my 31.
MH

----- Original Message -----
From: anglersoutreach
To: WanderlodgeForum@yahoogroups.com
Sent: Sunday, November 19, 2006 2:55 PM
Subject: [WanderlodgeForum] Re: I NEED A 4.11 Differential


Thanks Mike, you convinced me to stay with the mt40. Did your 31' come
with the Chevy or did you convert it? I worked for GM for about 20 yrs
as a technician and would really like ot go to a Chevy instead of
spending money on the 391.

Thanks, Billy





[Non-text portions of this message have been removed]

[anglersoutreach]

Mike, how would a 366 do in the Bird?

I have found a GMC 6500, I think it has a 366 in it. I will check the
ID #s on Monday to verify which eng. I know it has an allison in it.

Thanks, Billy

[Mike Hohnstein]

454 would be the minimum I would want, and that is just barely enough.
MH
----- Original Message -----
From: anglersoutreach
To: WanderlodgeForum@yahoogroups.com
Sent: Sunday, November 26, 2006 9:37 PM
Subject: [WanderlodgeForum] Re: I NEED A 4.11 Differential


Mike, how would a 366 do in the Bird?

I have found a GMC 6500, I think it has a 366 in it. I will check the
ID #s on Monday to verify which eng. I know it has an allison in it.

Thanks, Billy





[Non-text portions of this message have been removed]