dieselJon

Ok which would be better? I know the Allison is a 4spd lock-up, non-OD, tranny but the A518 is a non-lock-up, OD tranny. What is better for a DD/drag/2wd puller? The draggin' and pullin' coming a couple of years later. Going into a 87 1500 Suburban

1stGen545

Most 545 are non-lockup like mine. The 545 is much larger and stronger stock that any A518 even with upgreaded parts and if you up grade it like mine it is very strong. I am taking mine out becose the sled pull rules wont let me pull with it becose it was never put in a 1ton or smaller factory. It also has a much lower 1st. With no OD you will need a to try to find a set of 3.08 gears to run stock size tires. Its realy up to you.

dieselJon

I did some research and they said the RM is lock-up in 3rd and 4th only. Maybe newer ones are like that?

1stGen545

Yes some are and I wish mine was.

93beater

ever considerd the 727 i heard there pretty tough and put the power to the ground more than the a518

JD730

How do you figure? I don't want to pick a fight, but both are non-lockup transmissions and you are at the mercy of the converter.

The 518 is only a 727 with an overdrive added (its really a 2 speed planetary gear set, 1:1 and .69:1) with some other changes to activate the overdrive. The overdrive seems to have its own issues that are easily resolve, but the front section where the 3 speeds are is pretty much the same.

dieselJon

Have you seen one for sale? I have yet to see it. These 2 are for sale and I can get either on shipped to my door with everything needed for less than $1000, plus I would also have to find a 3.07 rear or I will be at the mercy of the Chevy 10 bolt 2.73 rear.

1stGen545

You can use a Dana 71 like in the dodge cummins 1st gens with and auto 89-93. If you can get the AT 545 with all the adapters for $1000 thats a great deal. Is that starter, Flywheel housing, flywheel and every thing? Mine has driver side starter( much more $$$ than a pass side and harder to find) most have a pass side starter and it gets in the way of the exhaust. You can get around it but its close in a 1st gen.

haloman

a 2.73 rear would be sweet tho if you kept the power down.

dieselJon

1stGen, it includes trans, adapter, converter, starter, crank spacer, and flex plate.

Halo, that diff needs to go. Every time I shifted into drive or reverse, it went CLUNK! really loud. I had a friend look underneath to make sure it wasn't the u-joints, nope, not them.

haloman

That sucks, You would be able to go 140+

dieselJon

Anyone else?

Also, how would a Chevy 10 bolt 2.73 hold up to about 300 hp? I am thinking (for now) just a turbo upgrade and getting my stock injectors rebuit. Maybe even a 12cm housing. OH and a BHAF.

dieselJon

Ok guys. I am going to bite the bullet. But still a little undecided. I know parts for the A518 is plentiful but what about the 545? I think being able to say "Yea, it has the Cummins and the Allison" would be a good coolness factor I am leaning more towards the Allison as it is cheaper by about $20. Plus in stock form the Allison can handle more.

Anything else?

Jon

1stGen545

Parts are easy to find and cheep. there is a shop here that only dose HD Allison work

mhuppertz

The 12 bolt has tapered axles and will twist in two the first time you romp on a 300hp, 800lb/ft Cummins, and since they are retained by c clips the wheel and axle piece will leave you at the worst time! Been there, done that.. Go with a very well set up Dana 60 or a stock Dana 70.