Community Forums

SpaceBall1 · 06-27-2022, 05:55 PM

Has anyone replaced an Allegro Bus Fan Gear Box on a Powerglide Has anyone replaced an Allegro Bus Fan Gear Box on a Powerglide Chassis?
2015 40SP
Wondering if it’s DIY or what the mechanic will need to get to the gear box, remove the fan and replace gearbox, drive shaft and find clutch.?
Any assistance appreciated.
- Mike
2015 40SP

RangerIV · 06-27-2022, 08:11 PM

It would be a tough DIY project laying on your back under the coach. If you have access to a lift or pit it still can be a big job. You need to remove the steel shield, disconnect the driveshaft and the gear box and the fan. I had a leaking gear box that was replaced under warrant at Bay Diesel in Red Bay. The tech had all the tools and experience replacing many gear boxes and it took him a few hours. If your coach is road worthy I would take it to a good mechanical shop. Tiffin recommends Rush truck centers if 1 is in your area.

1doodadd · 06-27-2022, 09:13 PM

I took mine out to reseal it because it was leaking and New keyway installed for the input u-joint. If you have the tools its a doable job. The hardest part was breaking the main fan bolt loose, just one, due to a very confined space. Your part number is a 412M type F gear box. You can look it up on the mfg. website Curtis Machining. Your gear box is specific to Tiffin and only available through Tiffin. Curtis will not talk to you about it I tried and was told NO. This was my write up . The second link is one on ebay for sale. If you consider the one on ebay make sure the shafts are the correct length for your application input, output

https://www.irv2.com/forums/f106/tif...ox-575999.html

https://www.ebay.com/itm/26478467864...53.m1438.l2649

SpaceBall1 · 06-27-2022, 11:05 PM

Thanks for the great information and links. Did you pull the bottom steel covers in order to reach the pump? Tiffin suggested it could be done from the rear,
But I don’t see how.

1doodadd · 06-28-2022, 06:47 AM

Did all the work from the bottom make sure you use jack stands in case you loose air and air bags deflate. If you do buy one from ebay as a replacement I would replace the seals. The correct part numbers are in the write up along with the New seal sealant.

garykk · 06-28-2022, 08:29 AM

Looking at the pics on the links to eBay and the repair, it appears that the gearbox shaft on eBay may be too short. Probably why Tiffin has a proprietary gear box.

DRM901 · 06-28-2022, 10:27 AM

Just curious, what caused the failure? Had the oil been changed regularly (every 2 years)?

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TUCSONRAIL · 07-12-2022, 04:23 PM

I had the fan gearbox and fan clutch fail, a $7000.00 repair. $3786 for the gearbox and $1034 for the fan clutch. It took an experienced tech at Transwest 7 hours to do the job. It actually took a lot longer because of frozen rusted bolts, but they honored the original estimate.

weighit · 07-12-2022, 08:49 PM

I bought a gear box from Tiffin to keep just in case, it came in a nice wooden box and I really hope never to need it, but did not want to be stuck somewhere waiting for parts. At the time I purchased it Tiffin said they had zero in stock and would ship the one I ordered when they got it in. Took about 4 weeks to get it to me.

langtons.g · 07-13-2022, 09:51 AM

Mike. I have a 40SP as well. Have replaced mine twice, once Bay Diesel in Red Bay and then FreightLiner Redding. Redding asked me not to bring it back, the mechanic didn't have lift to get it up. He took most of a day, very$$$$. It is a big job. I'm looking for seals for the last one (I kept it for a spare but not having luck on seals.) Anyone have advice???

SpaceBall1 · 07-13-2022, 10:14 AM

This coach has impeccable maintenance records and the fluid was changed as listed in the manual. I suspect the seal failed as you can’t see the leak as it’s got a pan and then the bearings seized.

SteveBev · 07-14-2022, 08:26 PM

Did Tiffin give you a lead time for getting the parts you need? I have been waiting for cooling module. keeps getting pushed back, now its been pushed back to October. Cooling module is the entire radiator assembly.

Crasher · 07-14-2022, 08:37 PM

Guess I must live right. The first time I had mine inspected and changed was @ 50,000 miles. The oil looked pretty good yet. I now have 85,000 on it. Still no leaks, but will have it changed again. I might just buy a spare to carry in the event of a failure. I do carry a spare DEF head, but have not had any issues with the original one.

Bill Overall · 07-15-2022, 04:26 PM

I thought mine was leaking, had oil all over it but it wasn't wet just kind of caked on. I could not find a service record for it and the coach had over 30k on it. I talked to Tiffin and ordered the newest gear box and new shaft after they looked at my pictures. I was going to do it myself but for some reason ran out of confidence, so I had a shop in Vancouver Wa. do it. at first I was happy and even started so on the forum. but after a couple of days I started looking at it and became very disappointed they made an unholy mess inside the coach, before leaving it I even stated to the service advisor to make sure not to make a mess and he assured me not to worry. So after 6hrs of cleaning I calmed down and moved on. Well that wasn't the end of it, we left for Boise Id. and when we pulled into the campground to register there was a loud and I mean loud sheeling sound coming from the eng. when restarting, we made to our spot and then I started to look and found the yoke to the gear box shaft free turning. long story short I removed the hatch cover and found the allen jam nut to the keyway loose and the actual jam nut on the other side missing and when I took it apart the key was laying on the gear box mount. I carry plenty of tools I just needed some small parts all that were found at tractor supply. after going thru all of that I wish I would have just done the job myself. it's not a technical job just hard to get to. After I got home I started to look and the original gear box, the oil was bad but it had 22 of the 24 oz required and it seemed to me it just may have been dirty because of the fan blowing on it, even the gears and bearing looked good so I probably should have just serviced it but maybe I was over worried about it because of all the things I read about them. The good news is it's not a worry anymore. Good luck however you decide to do it. B.O