Community Forums

Rummy · 10-01-2017, 10:32 PM

Looking at 2009 coach with upgrade from 450isl to a 500ISM but still has Allison3000 tranny. According to Allison a 500 should be mated to the 4000. Does anyone have any experience with a 500/3000 drive train? I am looking for info to help with decision on purchase.

CountryB · 10-02-2017, 06:49 AM

Are you sure the transmission is not the 4000 series?
Usually when the "optional" engine upgrade is purchased it comes with the upgraded transmission too.

Look under the Coach and see if you can identify (there is a model tag on the left side). I believe these pictures correctly show the external difference in the 3000 and 4000 series based on my research and downloads. If anyone has additional info to share, please post.

The photo captions were added by me.

Steve Ownby · 10-02-2017, 08:42 AM

Quote:

Originally Posted by Rummy

Looking at 2009 coach with upgrade from 450isl to a 500ISM but still has Allison3000 tranny. According to Allison a 500 should be mated to the 4000. Does anyone have any experience with a 500/3000 drive train? I am looking for info to help with decision on purchase.

What is the coach and why do you think it's a 4000? I have never seen an ISM with anything but a 4000 mates to it.

Smitty77 · 10-02-2017, 10:57 AM

OP - Do some more fact checking on this with whoever is selling it... Quite a bit of surgery involved to change over form ISL450/3000 to ISM500/4000. Usually the differential and axles would also need to be swapped out. Air bags logistics, etc...

Is it possible the owner pumped up the ISL450 via so after market gizmo? Or more probable, ISM450 upgraded/reprogramed up to ISM500?

Best to you,
Smitty

Rummy · 10-03-2017, 11:43 PM

The coach is 2009 Imperial Bali, standard equipment lists 425ISM OPTIONAL EQUIPMENT UPGRADE 500ISM cost of upgrade $30,000 advertisement lists 500ISM AND Allison 3000. I have seen the same situation in adds for 2008&2009 Dynasties. I will get back to the seller. Coach is quite a drive didn't want to make the drive yet until I was clearer on the engine upgrade.

I appreciate your help, let you know what I find.

Steve Ownby · 10-04-2017, 06:29 AM

Quote:

Originally Posted by Rummy

The coach is 2009 Imperial Bali, standard equipment lists 425ISM OPTIONAL EQUIPMENT UPGRADE 500ISM cost of upgrade $30,000 advertisement lists 500ISM AND Allison 3000. I have seen the same situation in adds for 2008&2009 Dynasties. I will get back to the seller. Coach is quite a drive didn't want to make the drive yet until I was clearer on the engine upgrade.

I appreciate your help, let you know what I find.

Have the owner give you the coach number. Call REV tech support and ask for the “data card” on that coach. They can also send you the window sticker.

I guarantee the transmission is a 4000.

Gary RVRoamer · 10-04-2017, 09:16 AM

The other possibility is that the ISM was de-rated to keep within the 3000 torque & Hp spec. Monoco/HR (now part of Rev Group) should be able to tell you exactly what it is. You need the VIN, though, so they can look it up.

I would not put much faith in used RV ads - they are often full of errors. heck, I see claims of Allison trannies in Ford F53's!

jimmy braden · 10-05-2017, 10:47 AM

Everything I see says the 3000 is rated for 1250ft/lbs and 450 hp. Certainly in the range of lowend ISMs (280-350 hp).. but those were not put in Rvs. So I think the odds are good its a 4000.

Rummy · 10-05-2017, 12:47 PM

Thanks all, I talked to the Monaco service center this morning, I found the coach I am looking at does indeed have the 4000Allison transmission. Thanks Steve for the suggestion to call them.

Bob Drum (Rummy)