Gear switch from 3.42 to 3.73 or 4.10

[TDEvans]

Hey guys I have a friend looking at a 2015 3500 6.7 Dually 4+4 but it has 3.42 gears in it,he"s not sure that gearing will work pulling his 16,000 fiver,anybody got a ball park figure to switch up to 3.73 or 4.10s,Any comments are welcome,Thx.

 

[jhenderson]

It won't be cheap! Gears plus install kits( some will say reuse the old bearings but you can't count on getting them off undamaged) plus someone who knows how to get it right th first time all add up. I wouldn't count out the 3.42s. I tow a 9 ton GN dump on a regular basis with 3.42s. Never had a problem yet. I just lock out 6th.

 

[gsbrockman]

Expect around $2,000 to $2,500 for parts & labor.

 

[JackFate]

Ok , I'll bite I got 3:42 & I've wondered if I would be better served with 3:73/4:10 's . I have owned 3:73 on a v10 350 all around worked well 3 sp auto plus od .and had an 4:10 454 3sp auto 3500 suburban . These were gassers but with only 3 speeds. With 6 speeds + the toque of a diesel the only way I'd go to lower gears was because I was ALWAYS towing. Like was said just lock to 5 , 16k is in range for 3:42

cheers

 

[AEdelheit]

We re geared our 2014 2500 to 4.10 gears through the dealer, used OEM parts and kept the warranty and it was right at $3000 OTD.

 

[EGroeneveld]

Hey guys I have a friend looking at a 2015 3500 6.7 Dually 4+4 but it has 3.42 gears in it,he"s not sure that gearing will work pulling his 16,000 fiver,anybody got a ball park figure to switch up to 3.73 or 4.10s,Any comments are welcome,Thx.

16K fiver is still way under the tow rating of that truck with 3.42 gears. I won't worry about it. 1st gear is pretty low to match it perfectly.

I have the 4.10 in my 2016....which fully loaded with toyhauler or truck camper/enclosed trailer is overkill. I don't mind the low gears in the hills of Oregon. But when I hit the 70, 75 and 80MPH zones the low gears kill my mileage. My next truck won't be 4.10s unless we have a 20k toyhauler by then (not likely)

 

[kthaxton]

If he intends to buy it regardless of gear swap costs/need, he should just get it and try it first before deciding (or random internet guys deciding) whether it will suit his needs or not.

Coming from the gas engine world....it is hard to fathom how such high gearing will work....but it does when you have 650-800 ft/lbs torque at 1500 rpm.

 

[Cummins12V98]

We re geared our 2014 2500 to 4.10 gears through the dealer, used OEM parts and kept the warranty and it was right at $3000 OTD.

Yes you had a 12 mo 12,000 mile warranty after the gear swap.

 

[shorthorn]

I pull a 14k 5er with my 2014 with 3.42 gears. It really does great. At speedsspeeds of 60 and lower, I locked it in 5th. At 70-75 themail truck has no problems in 6th until it hit the Smokey Mountains.. then locked in 5th again and all is well.

I have the 68RFE in my truck. In 5th gear with 3.42 rear end works out to about the same final drive ration as 6th gear in a 4.10 rear end.

See what Trans it has too... Aisin has lowered gears for 1-3 which would make the 3.42 even less of an issue

 

[AEdelheit]

Yes you had a 12 mo 12,000 mile warranty after the gear swap.

Actually we kept the factory and extended warranty since the dealer did the work.

 

[dfb]

We have a 15 3500 megacab sb wth AISIN and 3:42s. Towing a fiver at 13000 lbs, gvwr is 16000. We just did a x country trip. I use tow haul mode with full exhaust brake. Towing, the truck stays in 5th gear. When hitting a grade the truck shifts into 4 th gear but shifts back into 5th again then back to fourth. So I just keep it in 4th going up grades. Going from Las Vegas to flagstaff in a head wind 8.3 mpg.... most refills were about 11 mpg with a high of 12.2... the PERFECT GEARING I WOULD THINK is 3:73... a shop in my area will swap out both the front and rear ring and pinions for 1200.00. However, 3:42 while not perfect is still better than my 04.5 ram with nv5600 and 4:10s...I'd climb a hill in 5th at 52 mph, the new truck pulls that same hill over 70 mph...

 

[Cummins12V98]

^^^^ I disagree you are around 1700 in 5th at 60. That is a great RPM and the fact solo you get the best MPG with the 3.42's.

 

[SnoKing]

Hey guys I have a friend looking at a 2015 3500 6.7 Dually 4+4 but it has 3.42 gears in it,he"s not sure that gearing will work pulling his 16,000 fiver,anybody got a ball park figure to switch up to 3.73 or 4.10s,Any comments are welcome,Thx.

If the truck has the Aisin with lower 1st and 2nd gears vs the 68RFE, it is a no brainer to stay with the 3:42. We just towed our 16K 5th wheel from Washington to Arizona with 3:42 gears. In tow haul it will not try to shift to 6th until over 65 MPH. On some grades it would hunt between 4th and 5th, so I just locked it in 4th until I crested the hill.

Swapping geard at the dealer gives you the one year parts warranty on them, not the vehicle warranty. Hopefully you will never have to face the issue debate with a dealer. Maybe your home dealer might slip it by, however have an issue away from home could have a different ruling. SNOKING

 

[Cummins12V98]

Dave Smith made it VERY clear if I did swap gear ratios I would have a 12mo 12,000 warranty NOT the 100K powertrain any longer.

Anyone that thinks this is not so please show me the warranty is not effected in WRITING!!!

 

[Gonzo 1066]

My 2013 3500 has 4:10s. The next one will be at least 3:73s,

 

[HWTG]

I had 3:73 gears in my 2013 Ram. Pulling my 16K toy hauler, I would always have to drop a gear otherwise the transmission was constantly shifting.

I ordered my 17 with 4:10 gears. It is great for towing, and my mileage is actually better with 4:10 than it was with 3:73 gears. I would walk away from anything with 3:42 gears.

 

[Cummins12V98]

"I would walk away from anything with 3:42 gears."

I towed 29K combined with 3.42's and now 33K with 4.10's. The 3.42's pulled every 6% grade along I-5 in the OR, CA area about 5 mph faster. They are nearly identical gearing with 3.42's in 5th and 4.10's in 6th. So your pulling away statement is most likely not reality. Compared to the 3.73's I would agree.

 

[HWTG]

"I would walk away from anything with 3:42 gears."

I towed 29K combined with 3.42's and now 33K with 4.10's. The 3.42's pulled every 6% grade along I-5 in the OR, CA area about 5 mph faster. They are nearly identical gearing with 3.42's in 5th and 4.10's in 6th. So your pulling away statement is most likely not reality. Compared to the 3.73's I would agree.

3:73 in 5th is similar to 4:10 in 6th.

Drive what you want, you couldn't give me 3:42 gears for towing.

 

[gsbrockman]

16K fiver is still way under the tow rating of that truck with 3.42 gears

The OP never mentioned the cab configuration....but if we assume it's a Crew Cab, that 16k fiver is "hardly" way under the tow rating of that truck if it's a 68RFE.

A 2015 RAM 3500 Crew Cab 4x4 DRW w/68RFE & 3.42's has a 16,660 max trailer rating and a 25,300 GCWR.
A 2015 RAM 3500 Crew Cab 4x4 DRW w/68RFE & 3.73's has a 18,660 max trailer rating and a 27,300 GCWR.
A 2015 RAM 3500 Crew Cab 4x4 DRW w/68RFE & 4.10's has a 21,660 max trailer rating and a 30,300 GCWR.

Conversely....here's the AS69RC specs :

A 2015 RAM 3500 Crew Cab 4x4 DRW w/AS69RC & 3.42's has a 20,510 max trailer rating and a 29,300 GCWR.
A 2015 RAM 3500 Crew Cab 4x4 DRW w/AS69RC & 3.73's has a 23,510 max trailer rating and a 32,300 GCWR.
A 2015 RAM 3500 Crew Cab 4x4 DRW w/AS69RC & 4.10's has a 29,010 max trailer rating and a 37,800 GCWR.

https://www.ramtrucks.com/assets/towing_guide/pdf/2015_ram_3500_towing_charts.pdf page #5

 

[Cummins12V98]

Based on my personal experience towing 29K combined 68RFE and 3.42's with only issue getting the load rolling on grade I would buy this combo towing the same with NO hesitation!!!

Seems RAM knows what they are talking about.

"A 2015 RAM 3500 Crew Cab 4x4 DRW w/AS69RC & 3.42's has a 20,510 max trailer rating and a 29,300 GCWR."