3.42 to 4.10

[NIsaacs]

When I need 4x4 I use it, loaded, empty, wet or dry. The cinder pit I haul out of, 4x4 is mandatory, it is steep. I watch the diesel sled pullers with big power running stock running gear, yet it is rare to see breakage. I am carful but don't worry about it much.

Nick

 

[SnoKing]

I hear mention a lot on locked/unlocked torque converters. I need some educating on this cause I don't understand. Does the truck do this on its own? Do I need to do something? This is my first experience owning this kind of truck. Long way to go!

Les, the TC clutches are unlocked when the vehicle is not moving so that you can put it in gear and run against the fluid coupling. As you take to the road the transmission computer determines when to lock the TC for "direct drive" without the slippage of the fluid coupling. typically the computer unlocks to shift gears and then re-locks. the advent of locking TC is what made them get similar MPG to what a manual transmission could do. SNOKING

 

[Dogpatch]

Thanks SNOKING. I wondered if there was a button I hadn't found yet LOL.

 

[dfb]

John, People do not want the fact's.

Also to me this there is no debate on what gear ratio to order if you buy a SRW truck equipped with the Cummins engine. Ram only offers one gear ratio and that is the 3:42 so except and let's move on. If you want a different gear ration than buy a DRW truck; end of story.

As pointed out to us that were at the TDR rally in Columbus IN., in 2013. Ram has done their testing and they have determined that the 3:42 differential ratio is all that is required for a SRW truck to tow within it's limits.

Jim

Not really end of story... The ring and pinion can be swapped out. I checked with a driveline shop. Do the front and rears is 2500.. I was thinking about going to 3:73s... However, after pulling the Montana great news! Previous 04.5 ram with the nv-5600 and 4:10s pulled our hill at 52 mph... New truck with 6.7 h. O . And 3:42s aisin pulled that hill at 65 mph....I don't get it....
Jim ,,, question. You said ram used 3:42s to keep the short bed within its throwing limits...... Go to the 2015 towing guide.... Go to 4x4 h.o. Mega cab tow ratings...srw vs drw Megaca ... Both the srw and the drw short bed Megan's have the same engine, same transmission and same rear axle ratios of 3:42... I know the dually is for th higher gvwr but how does a dually effect tow capacity. .? The SRW is rated to tow 16660 lbs... How ever, the dually is rated to tow 20330 lbs!!! What is this?... It's the SAME TRUCK! Anyone have the answer?

 

[Cummins12V98]

If you have a SRW 3500 and AISIN be happy with it you have the best of both worlds! Tow in 5th and solo hit 6th. You will regret changing the gear ratio.

 

[Cummins12V98]

Hard to tell with the downward angle of the pic but the RPM's are at or very close to 1,750 at 60 in 5th. Yes the converter is locked.

 

[Newsa]

Not really end of story... The ring and pinion can be swapped out. I checked with a driveline shop. Do the front and rears is 2500.. I was thinking about going to 3:73s... However, after pulling the Montana great news! Previous 04.5 ram with the nv-5600 and 4:10s pulled our hill at 52 mph... New truck with 6.7 h. O . And 3:42s aisin pulled that hill at 65 mph....I don't get it....
Jim ,,, question. You said ram used 3:42s to keep the short bed within its throwing limits...... Go to the 2015 towing guide.... Go to 4x4 h.o. Mega cab tow ratings...srw vs drw Megaca ... Both the srw and the drw short bed Megan's have the same engine, same transmission and same rear axle ratios of 3:42... I know the dually is for th higher gvwr but how does a dually effect tow capacity. .? The SRW is rated to tow 16660 lbs... How ever, the dually is rated to tow 20330 lbs!!! What is this?... It's the SAME TRUCK! Anyone have the answer?

I believe the DRW has a different front end. It won't dip as far when braking hard and towing. But the SRW has a better ride

 

[Cummins12V98]

SRW and DRW 3500's have same front end. SRW's better ride I disagree, I have the rear air ride on my 3500 DRW and my Son has a 3500 SRW with rear air ride and I don't notice a ride difference. Also I have ridden in SNOKING'S 3500 SRW and did not notice any difference between his ride and mine. I can't comment on the 13 and newer DRW with standard rear suspension.

 

[AH64ID]

Hard to tell with the downward angle of the pic but the RPM's are at or very close to 1,750 at 60 in 5th. Yes the converter is locked.

So I started looking at the tires a little more. It seems that Ram has the Nexen's at 673-675 rev/mile (2 different models), yet every other 235/80R17 is ± 649-654 rev/mile. The General's used up thru 2014 are 649 rev/mile.


With 675 rev/mile 1750 rpms, 4.10's, and the Aisin in 6th is 60 mph, but at the 654 rev/mile that Michelin's are it's 62 mph... or at 60 mph it's 1689 or 1679 at 649 rev/mile (also a common 235/80R17 rev/mile).

Very odd that the Nexen's are so much smaller than other 235/80R17's, but it does explain your speddo reading 60 at 1750, when it seems you are probably going 62. Pretty big change considering they are the same "size" tire.

 

[NIsaacs]

Go to the 2015 towing guide.... Go to 4x4 h.o. Mega cab tow ratings...srw vs drw Megaca ... Both the srw and the drw short bed Megan's have the same engine, same transmission and same rear axle ratios of 3:42... I know the dually is for th higher gvwr but how does a dually effect tow capacity. .? The SRW is rated to tow 16660 lbs... How ever, the dually is rated to tow 20330 lbs!!! What is this?... It's the SAME TRUCK! Anyone have the answer?

When you add all your personal must haves to the SRW, it runs out of payload quick. The 20,330 lb trailer will have about a 4066lb pin weight or 20%, that will far exceed the srw payload.

Nick

 

[gsbrockman]

When you add all your personal must haves to the SRW, it runs out of payload quick. The 20,330 lb trailer will have about a 4066lb pin weight or 20%, that will far exceed the srw payload.

Nick

Exactly, Nick. The obvious answer is the 12,300 GVWR of the SRW vs. the 14,000 GVWR of the DRW. 1,700 lbs more of pin weight, cargo or passengers can be utilized in the DRW. An oddity dfb may have overlooked is the towing capacity of a 4x4 MegaCab SRW is more with the 68RFE vs the AISIN (16,800 vs. 16,660). Apparently there's 140 lbs more "guts" in an AISIN equipped truck----and subsequently 140 lbs less towing capacity.

The AISIN really shines with 3.73's over 3.42's and it shines most with 4.10's over 3.73's. When comparing all DRW trucks with 3.73's or 4.10's, the AISIN shines quite alot more over the 68RFE. The AISIN shines less in the SRW applications---where it is actually under utilized, IMO.

 

[Deleted member 995608]

If you have a SRW 3500 and AISIN be happy with it you have the best of both worlds! Tow in 5th and solo hit 6th. You will regret changing the gear ratio.

I planned to pony up the money for the R&P swap when I bought my truck a few weeks back. Now that I have it, I'm not too sure I'd swap now. I have to get hay this Friday, so I'm gonna play it by ear for now and see how I like it.

 

[AH64ID]

I planned to pony up the money for the R&P swap when I bought my truck a few weeks back. Now that I have it, I'm not too sure I'd swap now. I have to get hay this Friday, so I'm gonna play it by ear for now and see how I like it.

I honestly think it depends on how much time you spend loaded below 25 mph.

 

[SnoKing]

We were at 22050 combined coming down to Arizona, and thought the gearing was great, walked up 58 East of Bakersfield to Tehachapi like it was not there.

The long legs bobtail are a BIG BIG plus.

I also was one of those that thought the SRW should have lower gears. However after 14 years with 4.10's in the 2001.5 it is really nice to cruise on the free way at low RPMs. We drove most of one day on the way back from Colorado at 80 MPH like we were out for a Sunday drive. Even DW drove at that speed comfortablely.

Snoking

 

[Cummins12V98]

I

So I started looking at the tires a little more. It seems that Ram has the Nexen's at 673-675 rev/mile (2 different models), yet every other 235/80R17 is ± 649-654 rev/mile. The General's used up thru 2014 are 649 rev/mile.


With 675 rev/mile 1750 rpms, 4.10's, and the Aisin in 6th is 60 mph, but at the 654 rev/mile that Michelin's are it's 62 mph... or at 60 mph it's 1689 or 1679 at 649 rev/mile (also a common 235/80R17 rev/mile).

Very odd that the Nexen's are so much smaller than other 235/80R17's, but it does explain your speddo reading 60 at 1750, when it seems you are probably going 62. Pretty big change considering they are the same "size" tire.

I changed to the MS2's at 200 miles and sold the NEXENS.

 

[Cummins12V98]

I planned to pony up the money for the R&P swap when I bought my truck a few weeks back. Now that I have it, I'm not too sure I'd swap now. I have to get hay this Friday, so I'm gonna play it by ear for now and see how I like it.

When I bought my 11HO dually it had 3.42's. DS offered to swap both diffs for $1,500 a steal! After towing a combined 28k I left the gears stock. Only negative was getting the load rolling on a grade. The Aisin would have resolved that.

 

[AH64ID]

I

I changed to the MS2's at 200 miles and sold the NEXENS.

I know. If you didn't have the speedo reprogrammed it is slightly off and why you show 1750 rpms at 60 when you should be below 1700. The Nexen's are a very small 235/80R17. They are 3% smaller than the MS2's of the same size.

 

[Cummins12V98]

I know. If you didn't have the speedo reprogrammed it is slightly off and why you show 1750 rpms at 60 when you should be below 1700. The Nexen's are a very small 235/80R17. They are 3% smaller than the MS2's of the same size.

OK, I will hook up my garmin when I get home to see where I am. So in reality I should be 62mph at 60.

 

[AH64ID]

OK, I will hook up my garmin when I get home to see where I am. So in reality I should be 62mph at 60.

Yes based on 1750 rpms, 4.10's, Aisin in 6th, and Michelin MS2's in 235/80R17 you should be doing 62 mph.

 

[spoon059]

An oddity dfb may have overlooked is the towing capacity of a 4x4 MegaCab SRW is more with the 68RFE vs the AISIN (16,800 vs. 16,660). Apparently there's 140 lbs more "guts" in an AISIN equipped truck----and subsequently 140 lbs less towing capacity.

I noticed that too... really makes you wonder. We all know that GCVWR of the 2500 is artificially determined by the 10K rating for a class 2B truck registration. The 3500 with the Aisin is certainly a more stout driveline than the 68RFE, but I wonder why the GVWR of the 3500 isn't a little higher with the stronger transmission...