The Breakaway and I spent more than an hour with he North Florida Allison field tech. He did not think there was anything wrong with the AT 542 other than it being an AT 542. He talked with the Cummins expert who said “those old 5.9s will run forever wide open, don’t worry about the rpms”. When I asked about a 2000 he said that would not be a problem to install. I said I had a write-up to work from and he said “I’ve got it figured out already.” Then he said a 2000 would be expensive and I should look for a 1000 . He said the 1000 was stronger than the 542 so I could save a lot by going that way.
I Know the engine looses power the faster it spins , I am considering looking for a 1000 series 5 speed. It seems they can be had for about $1000-$1500 without a core charge.
Any Words of wisdom on this plan of action. Also the Allison tech said my tach is reading incorrectly. Is a direct replacement available if not what would be a good replacement.
Thanks
Wayne

you'll have to drive thousands and thousands of miles to recover the retrofit cost with fuel savings 5sp vs 4sp. In fact, if the 1000 is 5sp w/o OD, savings will be negligible IMO.
What bugged me more the fuel consumption, running a non OD Alli in a 5.9 Breakaway, was limited cruising speed. I am not aware whether Turtle has done anything to increase it.

Good point. When I installed the Gear Vendors in my Barth, '85 454 TH400something, it was more for the engine than for fuel ecomomy. I wanted to be able to cruise at 60mph at something less than 3000RPM. One of these days, I'll install a tach and see what it's actually doing. I'm guessing about 2400RPM.

wanna swap???


http://www.4btswaps.com/forum/...nd-swap-guide-thread

Doug, I presume you're not talking about Old Blue.