Ram 5500 w/ 4.88 gears

N

NYSUPstater

Well-known member
Was told recently about a fella who bought said truck (used w/ RV flatbed) and the Asion tranny and claims that at hiway speed (70-75), RPM's were below 1600. I didn't think anything above a 3.31 ratio would be that low of RPM's. Is this possible to do w/ the Asion and 4.88? Or are there extra gears within the Asion trans. Claims it's a 6 speed. Plus, the Asion is a Allison in disguise built by Allison, but can't call it that due to Allison being pared up w/ D-max/GM. IDK- just from what was told.
 
S

sengli

Well-known member
My RAM 3500 with the aisin tranny has 3.73 gearing and at 70..pretty sure I would be turning over 2200 RPM's. I never drive that fast towing ever, but on an occasional run w/o a tow vehicle I have driven that speed for short periods of time. At 60 I am right about 1600 RPM.
 
LBR

LBR

Well-known member
Lol....another "over-compensating" story....

We have a 2003 Ford F-550, 4.88:1 gears (Dana 135), automatic, 19.5" tires (brand new), that we will be driving today...will run it at 1600 RPM for the MPH, then buzz it up to 70 MPH for the RPM. This will give everyone a look at 4.88 gearing and you should then appreciate the gearing you now have!

With a little researching on the 2 transmissions drive gearing for a final math correction, we will be able to put this story to rest.
 
porthole

porthole

Retired
NYSUPstater said:
Was told recently about a fella who bought said truck (used w/ RV flatbed) and the Asion tranny and claims that at hiway speed (70-75), RPM's were below 1600. I didn't think anything above a 3.31 ratio would be that low of RPM's. Is this possible to do w/ the Asion and 4.88? Or are there extra gears within the Asion trans. Claims it's a 6 speed. Plus, the Asion is a Allison in disguise built by Allison, but can't call it that due to Allison being pared up w/ D-max/GM. IDK- just from what was told.
Click to expand...


Somebody is smoking crack - he probably gets 22 MPG and 21 MPG towing.


Aisin - is a Japanese conglomerate, probably the largest transmission maker in the world.

The Aisin is not an Allison in disguise.

It is not an Allison, which is an American manufacturer.

The Allison - GM exclusive thing has past.

I still don't get why RAM makes the Aisin an option.

All three are very similar in ratios and hardware size.
All three have excellent, proven track records.

For maintenance, the Allison wins. With an external spin on filter you could get away with just changing that filter every year and topping off the fluid.

The Allison's weak point is not the trans but in how it operates cold, and GM's crappy transmission cooler lines (well theres that and the fact it is in a GM)
 
ramdually4100king

ramdually4100king

Well-known member
I own that exact truck. Ram 5500 with 4.8 rear. At 65mph I’m at 2300rpm and at 75mph I’m screaming at 2800rpms. Normally cruise at 65mph when not towing due to the 19.5 tires are rated for 75mph only. When towing I do 60mph. I get 14mpg no tow and 10mpg towing my 20k cyclone.


IMG_2394.jpg


Sent from my iPhone using Tapatalk
 
SNOKING

SNOKING

Well-known member
porthole said:
Somebody is smoking crack - he probably gets 22 MPG and 21 MPG towing.


Aisin - is a Japanese conglomerate, probably the largest transmission maker in the world.

The Aisin is not an Allison in disguise.

It is not an Allison, which is an American manufacturer.

The Allison - GM exclusive thing has past.

I still don't get why RAM makes the Aisin an option.

All three are very similar in ratios and hardware size.
All three have excellent, proven track records.

For maintenance, the Allison wins. With an external spin on filter you could get away with just changing that filter every year and topping off the fluid.

The Allison's weak point is not the trans but in how it operates cold, and GM's crappy transmission cooler lines (well theres that and the fact it is in a GM)
Click to expand...

The Allison 1000 has reached it's torque limit and GM does not seem to be pushing them for a heavier duty offering. Both the Aisin and Ford's Torque Shift are very good transmissions. RAM's maintenance schedule for the Aisin is not to most peoples liking, along with their 6 months or 15K which ever occurs first engine oil change interval.

Chris
 
jayc

jayc

Texas-South Chapter Leaders
I have a buddy that had that same exact truck, Ram 5500 with tow bed. He hated it, the ride was terrible, the mileage was 8-10 mpg towing at 65. He never drove it bobtail, they have one of those tiny little Honda FIT's to run around in.

He kept his a couple of years and traded it for a Ram 3500 HO with Aisin and .410 rear gears and loves it! Much better ride and 11-12 mpg towing. He has a very heavy Carriage trailer.
 
SNOKING

SNOKING

Well-known member
jayc said:
I have a buddy that had that same exact truck, Ram 5500 with tow bed. He hated it, the ride was terrible, the mileage was 8-10 mpg towing at 65. He never drove it bobtail, they have one of those tiny little Honda FIT's to run around in.

He kept his a couple of years and traded it for a Ram 3500 HO with Aisin and .410 rear gears and loves it! Much better ride and 11-12 mpg towing. He has a very heavy Carriage trailer.
Click to expand...


11-12 mpg towing very heavy must be from lie-o-meter on down hill runs, as no one else is getting that kind of mileage, except on a single downwind flat leg.
 
B

BouseBill

Guest
Our 2008 F-450 with 4:88s turn almost 2400 at 65, but does seem to be the best fuel mileage at that RPM, right at about 10mpg towing
 
B

bwdt

Well-known member
The Allison does have a weakness when put behind the Cummins, The C-3 clutch wears out rather quickly if not modified. The cummins engine torque comes up much more quickly than the Duramax and causes the Clutch to slip prematurely. Ask me how I know.......LOL. The two transmission do look similar in design and possibly similar in operation...But that being said does not make the Aisin an Allison.......
 
LBR

LBR

Well-known member
Per my post #4 above....

1600 RPM = 43 MPH
2625 RPM = 70 MPH

Mythbusters final results....BUSTED!...lol
4e9e093656ad5699d56536d5ecf99819.jpg
2c9551e52d87f0a4768319055bcf4321.jpg
 
N

NYSUPstater

Well-known member
Thanks a lot for all the great replies. Personally, I doubted what I was being told on figures as it just didn't seem right. Never having anything "higher" than a 3.73 in my old 6.uh-oh, it ran 2000@70, so the low rpm's at hiway speed just didn't add up in my pea sized noggin. Now for a $6.00 question. Is it possible that the previous owner did do something different to the transmission?

As to the Asin being a clone to the Allison, Thanks to all for dispelling that myth that Ally was building /owned the Asin.
 
SNOKING

SNOKING

Well-known member
NYSUPstater said:
Thanks a lot for all the great replies. Personally, I doubted what I was being told on figures as it just didn't seem right. Never having anything "higher" than a 3.73 in my old 6.uh-oh, it ran 2000@70, so the low rpm's at hiway speed just didn't add up in my pea sized noggin. Now for a $6.00 question. Is it possible that the previous owner did do something different to the transmission?
Click to expand...

The Aisin has two overdrive ratios.
5th gear is .77 to 1
6th gear is .63 to 1

The Allison has two overdrive ratios.
5th gear is .714 to 1
6th gear is .611 to 1

So both the .63 Aisin and the .611 Allison are already very steep overdrive ratios. One would need a aux overdrive unit like Gear Vendors, however I do not believe they ratios available to would make up that many RPMs or are rated for the HP and Torque of these newest diesels.

BTW Here are the Ford Torqueshift ratios.
5th gear is .858 to 1
6th gear is .674 to 1
 
N

NYSUPstater

Well-known member
SNOKING said:
The Aisin has two overdrive ratios.
5th gear is .77 to 1
6th gear is .63 to 1

The Allison has two overdrive ratios.
5th gear is .714 to 1
6th gear is .611 to 1

So both the .63 Aisin and the .611 Allison are already very steep overdrive ratios. One would need a aux overdrive unit like Gear Vendors, however I do not believe they ratios available to would make up that many RPMs or are rated for the HP and Torque of these newest diesels.

BTW Here are the Ford Torqueshift ratios.
5th gear is .858 to 1
6th gear is .674 to 1
Click to expand...

WOW, great info. But why does the Ford seem to have higher numbers than the other 2? All 3 have pretty much same power/tq ratigs, so you'd think if all 3 have 4.10's, they'd be the same. Could be too as to why the Fords don't seem to get the same mpg results as GM/Ram do. Saying that, if that translates into just 1-2 mpg's, not a big deal IMO.
 
CarterKraft

CarterKraft

Well-known member
LBR said:
Per my post #4 above....

1600 RPM = 43 MPH
2625 RPM = 70 MPH

Mythbusters final results....BUSTED!...lol
4e9e093656ad5699d56536d5ecf99819.jpg
2c9551e52d87f0a4768319055bcf4321.jpg
Click to expand...

But the truck in question has a single .71 over drive and the mythical truck has a .63 double overdrive like the .67 ratio of the 6r140 in the 11+ Ford and the .61 OD in the Allison 1000.

That .6x gear ratio in the top OD makes a huge difference in highway RPM.
 
CarterKraft

CarterKraft

Well-known member
NYSUPstater said:
WOW, great info. But why does the Ford seem to have higher numbers than the other 2? All 3 have pretty much same power/tq ratigs, so you'd think if all 3 have 4.10's, they'd be the same. Could be too as to why the Fords don't seem to get the same mpg results as GM/Ram do. Saying that, if that translates into just 1-2 mpg's, not a big deal IMO.
Click to expand...

Hard to say, could have something to do with peak hp/tq numbers, parts interchangeably between models or ???

After coming from a 4r100 with the 3 speeds and a single OD the 6 speed double OD transmissions are one of the greatest improvements in these modern trucks (all brands) the upcoming 8-10+ speed tranny's might even improve that.
 
SNOKING

SNOKING

Well-known member
CarterKraft said:
Hard to say, could have something to do with peak hp/tq numbers, parts interchangeably between models or ???

After coming from a 4r100 with the 3 speeds and a single OD the 6 speed double OD transmissions are one of the greatest improvements in these modern trucks (all brands) the upcoming 8-10+ speed tranny's might even improve that.
Click to expand...

I can see gassers with a narrower power band benefiting from more gears, however with diesels having wide power band, I just do not see the need and the extra shifting that will occur. The time shifting gears is time not putting the power to the road.
 
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