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Ryanmcgrim
New Member
United States
4 Posts |
 Posted - 06/03/2009 : 2:45:45 PM
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Hello All,
And thanks in advance for all your help, I have been a lurker here for a while, to help me keep my bus on the road, but am in dire need of some personalized help this time around.
I am the proud owner of a 1989 Ford B-600, Blue Bird, with a Ford / New Holland 6.6L Turbo (Brazilian) Motor- AT545 - Air Brakes 66 Passenger (11 Window).
Over the last few year I have been converting her to a motor home. I am finally approaching the finish line as far as the conversion goes, but there is one final power train Issue that needs to be resolved.
Due to the gearing of the Rear end, she tops out at 48mph at almost 3,000 RPM, which is way too fast for her to spin. The problem is I can't seem to find Any info regarding my differential model, so I have no idea where to start as far as changing the gears, or the whole thing.I would like to at least be able to find compatible parts, then maybe have a professional drop it in for me, so I can save some money.
Do any of you good folks know what my options may be?
I have a Rockwell RS17140 mfmm 18
Serial AVA89041008
Air Brakes
Leaf Springs
Ratio is 6.43
I would like to change it to a 4.56 -4.88, just don't know where to start.
Any ideas? |
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Mechan1c
Top Member
USA
853 Posts |
Posted - 06/03/2009 : 5:30:38 PM
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| I'm not sure who your local suppliers are, but I'd call my local FleetPride which has a gear shop and tell them what I had, and see if the housing would accomodate a 488 gear set. |
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bwest
Administrator
United States
3820 Posts |
Posted - 06/03/2009 : 8:46:40 PM
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| I would think you could find a salvage yard around that could help. Just my 2 cents. |
Bryan |
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Ryanmcgrim
New Member
United States
4 Posts |
Posted - 06/08/2009 : 08:08:13 AM
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| Thanks Mechanac1c and Bwest for your replies. My local fleet pride unfortunately has gone out of business, and of the other two heavy equipment garages, one wants $2300 to swap out my rear differential, and the other wants $2000 to swap the gears out. This is so far beyond my ability to pay it is silly. I was able to find out that my rear end will take the 4.56 gears that I am looking for, My Differential is a Rockwell RS17140. My question is, knowing that I can fit the 4.56 gears into my rear end, does that rule out swapping out the complete rear end for another and is this something that a relative big equipment novice and some friends could do on our own? Does just changing the gears require very specialized tools and expert know how. Also, what do i have to know when considering finding either gears or a complete rear end, will any Rockwell 4.56 rear end gears work, or do i have to be specific to my model number. If I am doing a complete swap out, will any rockwell out of a school bus that has leafs and airbrakes work or do I have to find something more specific. Sorry for rambling on, I really appreciate your help. Basically I need to do this swap on the cheap, is this something that I could handle, I have worked on VW bugs and jeeps before, but am basically a quicklearning novice, never worked on anything this big before. Also, I am willing to drive 300 miles or so around asheville (Atlanta, Charlotte, Greenville, Knixville, Charleston to find what I am looking for in either parts or mechanics if that makes a difference. Thanks again, Ryan |
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Mechan1c
Top Member
USA
853 Posts |
Posted - 06/08/2009 : 09:19:04 AM
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| Labor-wise swapping the entire rear end seems like a ton of heavy work. Changing just the diff is not all that hard, but I've been at this for more than 20 years and we have all the tools and lifts. See if you can find a shop manual that shows the procedure. Common tools are used if the drop-in diff assy is set up by whoever you purchase it from. Not all Meritor gears interchange between rear-ends. Both quotes seem about correct since a rebuilt gearset costs about $1200. You'll need gear oil and axle gaskets. Watch your fingers! |
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origcharger
Top Member
United States
619 Posts |
Posted - 06/08/2009 : 09:39:19 AM
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I used to have 1988 and 1991 Ford buses with 7.8 diesel-4.30 gears and 6.6-4.88 gears. I ended up having to swap the 6.6 engine, tranny, and differential into the 91 bus after the 7.8 died.
Because of the higher torque output of the 7.8, the axle shafts and yoke on differential were larger.
I was able to swap because I had both buses here and had a good transmission jack that I could mount the heavy differential on.
Cheapest source for a differential is probably out of another Ford diesel school bus, I know most of them would not have came with that ridiculous 6.43 ratio that would have been more at home behind a gas engine. |
Operating; Seven T444Es, One MaxxForce 7, One VT365, Four DT466s, One E-450 6.0 and one Mercedes in a C2. |
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bwest
Administrator
United States
3820 Posts |
Posted - 06/10/2009 : 12:47:27 PM
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| My two cents again. I don't know about the numbers you gave but again a salvage yard will. I am realativly sure you can just change the carrier. All you need to do is block the front tires, jack up the rear end, pull the axle shaves and drive shaft, unbolt the carrier, (these things are heavy so be carful), then put the new carrier in and reinstall the shaves and drive shaft. Oh yea, drain the oil first it is less messy!! You should do fine. And one other thing, don't use too much silicone sealer you don't really want that stuff running around inside the rear end. |
Bryan |
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origcharger
Top Member
United States
619 Posts |
Posted - 06/10/2009 : 1:24:24 PM
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| As I noted above, Ford used differant sized axle shafts and drive shafts depending on engine power output. The driveshsft yoke could most likely be changed if needed BUT the axle shaft diameters must match the differential you intend to use. |
Operating; Seven T444Es, One MaxxForce 7, One VT365, Four DT466s, One E-450 6.0 and one Mercedes in a C2. |
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Ryanmcgrim
New Member
United States
4 Posts |
Posted - 06/21/2009 : 10:02:18 AM
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Thanks for all the help folks, so it looks like i could do a full swap if I found a similar bus on the cheap, but need to locate shop manuals, or compatibility lists before I can start, any ideas where to get this information?
Ryan |
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Rear Differential / Rear End Question
