Allison 4560 to 8LL

[renner]

Hi all new to forum, I didn,t want to jump on the other topic about auto to standard. Anyway I want to swap my allison4560 that's in a 2006 granite triaxle dump with a E7 375hp for an 8LL. just purchased truck not long ago and am very disappointed in performance of trany, just not suited for my area and use. I wanted to know if any of you know the best Mack salvage yard in east coast to go to for all the small parts as in pedals/cables and mounts. thanks in advance

[GearheadGrrrl]

The 8LL manual won't make it any faster- the splits are about the same as the Allison's. If the Allison is upshifting too early, etc. you can shift it manually or have it reprogrammed. Also, the Allison can have multiple shifting programs- touch the "program" button and see if it makes any difference,

[rsb502]

Yeah making the swap to an 8LL with a 375 aset it will be a turd for sure. Take it to have the trans programmed for performance if it doesn't already have it in the mode button. Most are setup with performance and economy shifting, one will be the default and the other is activated by pushing the mode button, but facts are an 06, 375 is a turd.

[rsb502]

Oh yeah it will be very expensive to swap too, then you will more than likely have to tow it to Mack to have the ecm reprogrammed to run with a manual. I don't know if it will run or not once you remove the inputs from the tcm, at best it will be in limp mode until its flashed at Mack. Best option if you really dislike it is to trade for one you do, you can't just swap parts around on newer trucks like you could non electronics.

[renner]

I don,t know my 2000 Volvo with 330hp DD 11 liter with an 8LL will run circles around the mack, same wheelbase, same tires, and same body. It needs more gears . Most guys around me have the same engine setup with 8LL and they are fine. Even manually shifting doesn,t help much, Another part is stopping the engine brake and trany just don,t work together and we are roaring thru brakes. Most of our driving is around rural roads not much more than 50mph, lots of stop and go and fair amount of off road.Its my mistake for not researching the auto first but I am into this thing now and it sits in the yard as nobody wants to drive it and we all want to use the older trucks. I have a line on a trany ,bellhousing and driveshaft, talked to mack already not a big deal re-programing ecm. Just don,t want to buy new pedals and misc stuff direct from Mack. Its a lot cheaper than having it sit around not used. no one knows of a dedicated Mack salvage yard that a private person can buy from?

[other dog]

I'd say the salvage yard is your best bet for all necessary parts. I know a Chevelle ain't a truck, but I put a 4 speed in a '70 Chevelle that was an automatic once. Went to the junkyard and bought all the parts out of a 4 speed Chevelle- I already had the transmission, I just got the clutch pedal, all the linkage,bellhousing, flywheel, and so on. I expected it to be a lot harder job than it was, everything was there for the 4 speed, all holes already drilled and tapped, so it was pretty much just bolt it in and go. I had expected to have to drill, tap, cut, weld, cuss, and all that, but I didn't.

[HK Trucking]

More proof that automatic transmissions have no place in class 8 trucks.

If someone hadn't made a big mistake and ordered that truck with a slushbox, you wouldn't be needin' to change it to a manual now.

[GreenGiant2]

i would try Casey's Truck Salvage. 716-681 0750. they are in buffalo new york.

[renner]

Thanks for info Green Giant 2

[GreenGiant2]

where in ny are you

[renner]

Eastern Long Island , Sag Harbor. we have Gabrelli Mack on the Island, but they aren,t exactly cheap or friendly.Only go there in a pinch.

[HK Trucking]

You also should get a spec sheet on that Allison trans & see what the gear ratio is in hi gear, then compare that to the gear ratio of the 8LL in hi gear.

Unless the 2 are fairly close, you may need to change your rear diff. ratios too.

[2stacksuperdog]

Eastern Long Island , Sag Harbor. we have Gabrelli Mack on the Island, but they aren,t exactly cheap or friendly.Only go there in a pinch.

So they are like that to everyone just not us CT people

[rsb502]

I dont know whats wrong with your truck but an allison in a truck running 50 or less stop and go should leave the others all day long, and the engine braking should be excellent. I know I get a lot of crap from some on here advocating allisons for vacational work but they are proven performers. your D11 is not the same as your aset in that granite, the aset engines from 04-06 are turds unless you get em set right, the DD11 will outrun it in that regard. I would get the trans and engine calibrations checked it should run better than the manual trans trucks in town for sure. If you swap to a manual you will have to reprogram the ecm, and if you want it to run the same speed as the others change the gears, allisons are true double OD your looking at a .67 6th gear that is gonna have a rear somewhere in the 5's if I had to guess which means with the .74 in that 8LL your gonna be geared way low the allison has a 4.70:1 forst the 8LL has a 14.56:1 your looking at second gear being the equivalent to your first now, then topping out about 55 mph at 1800rpm. I say something is wrong somewhere it should run great stop and go, and with the engine brake on it should go into lockup and drop gears to keep the rpm up you should be able to stop it without much brake pedal at all. I would take it to a Mack dealer and have them check the claibration and look for updates on the engine, you can have them set the shift points where you want em and with an aset they should be around 1600-1700 to keep it in a pull, also check for boost leaks in the intake system. just me I doubt its running right if its that bad in stop and go I never could keep up with the automatics here and my Granite was turned up quite a bit, obviously I could get em after we were up to about 40 then I had better gear steps but thru town it was no contest.

[HK Trucking]

The reason the Allison automatic doesn't have as low of a ratio in 1st gear (on paper) is that it relies on torque multiplication of the torque converter.

Even though the 1st gear ratio is 4.70:1, the engine can rev up into it's power band until the converter reaches stall speed, giving the same effect as a lower gear ratio.

[RFCDrum]

I've driven both Allisons in Macks and other trucks and I have had mixed feelings with it. Tomorrow I;m drving a Oshkosh cement truck with a 6 speed allison and 3 stage Jake with a Cat. That's another story.

Cheers, Rob

[renner]

It takes off fine, shifts 1-3 right where I would shift myself (Talking loaded). its the third to fourth spread, motors has to be flat out on the govener so that when it shifts it won,t dog out in fourth as the rpm drop is about 600 rpm and she falls off her torque curve and you basically flounder along not making any speed and if there is any and I mean any kind of hill forget it. the trany has a .67 OD but 5th gear is 1.00. rear ratio is 5.06. I am going to try a Allison dealer on the island to see if they can re-program it as a friend of mine runs a septic truck with almost same setup and he drove it sunday and said something isn,t right. As far as the 8LL goes yes I would have to get the OD one as thr rear ratio is pretty low, but like I said 55 mph is very rare around here on our roads, truck never sees the highway.Thanks for all the replies very helpful.

[GearheadGrrrl]

I agree- the problem is probably low power output from the engine and/or misprograming of the transmission. When you have the Allison reprogrammed, you might want to ask them to make sure 1st gear isn't locked out and have two programs, performance and economy, programmed into the transmission. I drove a Postal Service Mack with a mere 300 HP and an Allison and even at 80K gross weight it did fine.

[rsb502]

From your new description of the issue I think you main issue is low power from the aset engine. Mack has several updates for that engine to get it running better the low power at low rpm was a big issue with those engines and its all to keep the truck from smoking to meet EPA particulates requirements. In as delivered form those engines power band was high and they made almost no power below 1300rpm, if you can get Mack to fix that issue your truck will run fine if the low gears are good.

[renner]

Well today I took the truck to Van Burean automotive ,Strictly a Allison dealer. Anyway I got there and they hooked up the laptop and ran thru all the parimeters while driving the truck. It was pretty cool he could see if there was any clutch slippage, overheat, torque converter slip, low fluid level, you name it it could tell you what its been thru. Basically the trany has never had a problem , no codes, all the sensors are working properly. What he did do is totaly clear the shift history and lowered the gear it will downshift into during engine braking which will help it slow down.Clearing the shift history will let the trany re-learn with the first 500 shifts. He also told me he has driven many Macks with this very same setup and mine feels exactly the same, he also told me that he thought that Mack could re-tune the ecm to a little higher HP rating which would help the truck pull out of the gear shifts from 3-4 and 4-5 which are the widest spread.I guess all in all its a learning curve, just so used to rowing gears. Thanks for all the input and advice and will let you know how she runs loaded after a full day behind the wheel.