Eagles International Forum

Posted: **Wed Aug 16, 2017 7:53 am**

To recap the history about my project, around 10 months ago (time flies!) I purchased a 1982 Eagle conversion equipped with an Allison HT740 transmission and a 1994 vintage Cummins N14 500 HP engine. I drove it back from the west coast to Ohio. On the way home I lost reverse and the remaining gears started slipping badly. After returning home I was able to find an Allison MH4000 transmission that had been mated to a Cummins ISX engine in a motorhome for a very reasonable price from a motorhome salvage yard in Missouri. The salvage yard included the TCU and the touch pad shifter along with a short amount of wiring harness.

I had the transmission tested on a dyno at an authorized Allison service facility. To prepare the transmission for the dyno the technician replaced the fluid, changed the filters and replaced the multi-pin connector that had been damaged after removal from the motorhome. I was charged approximately $1500 by Western Branch Diesel for the dyno service so at the present time I have around $2600 invested in a functioning World transmission that the salvage yard told me had low miles.

My plan is to remove the shift cable assembly, trace the control cable back to the engine compartment and hopefully use that cable to fish the transmission wiring harness from the driver's area back to the engine compartment. I spoke with the foreman of a local automotive electric shop who is willing to wire the touch pad and ECU into the bus at my location for a reasonable hourly rate. While speaking with him he just happened to have in his desk a wall chart wiring schematic for Allison World Series transmissions so I'm confident he has the knowledge to wire it correctly. Hopefully I'll learn something while observing him work. I have a large garage with a grease pit I can use to lower the HT740 down into. I checked around and can rent a 2000 lb capacity transmission jack from a local tool rental center.

I'm wondering if I can remove the transmission from the coach myself or if I will need a helper to assist with the process. I was told by Western Branch Diesel that the torque converter clearance needs to be checked when changing to a different model of Allison transmission. While the transmission is out it would be a perfect time to re-ratio the differential so I can use all 6 gears of the World transmission. Can I use the transmission jack to do it? Any advice from those who have experience with an Allison upgrade or differential R&R would be most appreciated! -Jim

Posted: **Wed Aug 16, 2017 8:08 am**

You have a great bargain at the price you paid. You will never want to look back after driving with the MH4000. There are lots of ways to change the transmission. With a pit you can set up a come a long in the floor above the trans. and drop it down with cable. You will have to change the flex plate the 740 and world are not the same.
Lots of luck.
Jack

Posted: **Wed Aug 16, 2017 8:25 am**

It seems to me that it would take just as much time to drop the trans into the pit as it would to remove the engine and trans out of the rear. At that point you can go over a lot of the systems and make sure they are OK. The use of a pallet jack or make a dolly with caster wheels is not that hard to do but maybe your pit is now in the way. There is more than one way to skin a cat.
I think you have 3 gear ratios to choose from 3:73. 3:36 (3:38) and 4:11 the last 2 are getting harder and harder to find.

Wayne

Posted: **Wed Aug 16, 2017 9:24 pm**

Thanks Jack and Wayne for the advice. I found a flexplate to mate Cummins L10, M11 & N14 engines to Allison MD3050, MD3060, MD3550, MD3560, B300, B400 transmissions but my MH4000 isn't listed. The seller lists L10, M11 & N14 engines in the heading of the listing but underneath the photo it only lists L10 & M11 engines. Perhaps he made a mistake in listing the N14 since those other engines are smaller displacement.

As far as pulling the engine and transmission out of the back of the bus, I figured it would be less work if I could leave the engine in the bus and just drop the transmission. N14s weigh 2800 lbs and the transmission another 830 lbs so that's a lot of weight to pull out of the rear of the bus. All that weight makes the rear sit a little lower than the front suspension. I'm hoping I can adjust the torsilastic suspension to raise the rear a couple inches since the trailer hitch is so low to the ground.

Posted: **Wed Aug 16, 2017 9:59 pm**

You will be saving time to roll the engine out you are going to need drive shaft work anyways and dealing with the drop box it is a tight fit.If you have a concrete floor with a pallet jack they roll fairly easy 2800 lbs is just a few hundred pounds more that a 8v92 weighs and I roll the 8v92 and 740 Allison out by myself from Eagles

Posted: **Thu Aug 17, 2017 3:34 pm**

luvrbus wrote:You will be saving time to roll the engine out you are going to need drive shaft work anyways and dealing with the drop box it is a tight fit.If you have a concrete floor with a pallet jack they roll fairly easy 2800 lbs is just a few hundred pounds more that a 8v92 weighs and I roll the 8v92 and 740 Allison out by myself from Eagles

Thanks for the advice. I may go ahead and roll it out the back.

Next on the agenda is to determine the part number for the correct flex plate and spacer plates to mate the N14 to the MH4000. The Allison service manager told me that he'll need the engine and transmission serial numbers to research it. He also asked me if the engine had a #1 or #2 flywheel housing.

Posted: **Thu Aug 17, 2017 4:56 pm**

If it is a 740 it will be a number 1 bell housing all 740's used number 1 ,the 600 series did use a number 2 bell housing or a step down ring from number 1 to 2

Posted: **Tue Aug 29, 2017 7:16 am**

luvrbus wrote:If it is a 740 it will be a number 1 bell housing all 740's used number 1 ,the 600 series did use a number 2 bell housing or a step down ring from number 1 to 2

Thanks for the info regarding the bell housing. That will be one less part for me to look for.

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