Gear ratio

[GBBrown]

Looking at a dually for pulling a fifth wheel (14,000#) and trying to figure out best gearing with the Aisin transmission with cruising speed of around 60mph. Current TV in sig with the RFE hunts between 5th and 6th with just my 3200# TC. Pondering between the 3.73 or 4.10. Not much use having 6th gear if its locked out all the time.
thanks...

 

[Cummins12V98]

This topic has been ran over a few times! I have owned 3.42's with 68RFE and now 4.10's with AISIN. I towed 28-29K combined with my 11 HO 3.42's in 5th at 60 at around 1,750 rpm's. I tow 33-35K combined with current truck in 6th at about same rpm at 60.

The AISIN makes the 3.42's work great up to 28K or so because of it's lower starting gears. Bonus is the 3.42's will give MUCH better mileage solo than 4.10's. Don't even consider the 3.73's.

Look at the 3rd line up from the bottom. 29,300# SAE rated combined load!

 

[NIsaacs]

Looking at a dually for pulling a fifth wheel (14,000#) and trying to figure out best gearing with the Aisin transmission with cruising speed of around 60mph. Current TV in sig with the RFE hunts between 5th and 6th with just my 3200# TC. Pondering between the 3.73 or 4.10. Not much use having 6th gear if its locked out all the time.
thanks...

Everything you posted dictates a 4;10. The difference between a 3.42/3.73 is only about one tire size.

Nick

 

[RVTRKN]

Beating a dead horse again, 3500 DRW should be optioned with 4:10's, 3:73 at the minimum. Your going to read how wonderful the 3:42's are pulling massive loads. I grant it is capable with the 3:42's per the testimony/history of the owners of them, however a 3500 DRW is not meant as a grocery getter, or cruising to work at 70MPH empty on a daily basis. Yes they will get good mileage empty, however you buy them for pulling heavy pin/load weights, that's the reason for the DRW. The 6spd Aisin auto will help in running at lower RPM's with 4:10's. Of coarse its your choice, at least you have one with the 3500 DRW.

 

[Cummins12V98]

"Everything you posted dictates a 4;10."

Please explain???

 

[Cummins12V98]

Beating a dead horse again, 3500 DRW should be optioned with 4:10's, 3:73 at the minimum. Your going to read how wonderful the 3:42's are pulling massive loads. I grant it is capable with the 3:42's per the testimony/history of the owners of them, however a 3500 DRW is not meant as a grocery getter, or cruising to work at 70MPH empty on a daily basis. Yes they will get good mileage empty, however you buy them for pulling heavy pin/load weights, that's the reason for the DRW. The 6spd Aisin auto will help in running at lower RPM's with 4:10's. Of coarse its your choice, at least you have one with the 3500 DRW.

I guess the SAE chart I posted above means nothing. I have towed with both, if my combo was 29k or less I would be running 3.42's.

 

[Cummins12V98]

29K combined load with 11 HO Dually West Coast towing ZERO issues for 65K with well over 1/2 of those miles towing. Only thing that would have made it DA **** would to have had the AISIN with lower starting gears.



Second pic is at about 60K, with the machining still shows on the ring gear. Running AMZ/OIL 75/110 severe Gear 50K on lube.

Third pic about 50K on the AMZ/OIL Universal ATF.

 

[NIsaacs]

"Everything you posted dictates a 4;10."

Please explain???

The OP already did. He wants to cruise at 60 mph without gear hunting in 5/6th and don't want to lock out 6th. Since he made no mention of wanting to run 80 mph empty I assume that was not necessary.

Nick

 

[kthaxton]

Don't even consider the 3.73's.

OR.....you could consider the 3.73's and it will work just fine.....because in reality, 3.73 actually work as intended.
But, as NIsaacs said, if you only want to go 60 mph, go 4:10.

 

[RVTRKN]

I guess the SAE chart I posted above means nothing. I have towed with both, if my combo was 29k or less I would be running 3.42's.

As posted in other treads, I must have passed up the Coolaide when at a dealership.

 

[kthaxton]

As posted in other treads, I must have passed up the Coolaide when at a dealership.

It seems that to you, only your rare, partially unrelated experience is valid and the experience of others is not valid.....for some reason. You just cannot fathom that others could possibly have had a different experience than you. It seems you are attempting to serve the KoolAid.
Nobody told us our 3.42's will do the job fine.....They DO the job fine, this is how we came to our conclusions.
I still find myself in disbelief how well these things tow.

 

[Cummins12V98]

As posted in other treads, I must have passed up the Coolaide when at a dealership.

Real world experience is what I am spouting. Don't think too many have the same experiences as me.

When I came on this forum telling about my new 11 HO Dually and HEAVY DRV towing with 3.42's you would have thought the sky was falling (Hbarlow for one)! I had a price from Dave Smith to change out to 4.10 for $1,500 total (great price). But after realizing how well my truck performed and after talking to Stan Gozzi (Head west Coast Warranty guy) at MayMadness telling him what I was doing and asking him what he would suggest. He said just run it as it can't hurt it's self.

As I have said having the AISIN in that truck would have made everything GOLDEN.

You guys that are convinced otherwise that's fine, my comments are for those looking to buy a new Dually or even those concerned with 3.42's in a 3500 SRW. Just ask SNOKING what he thinks after owning his 3500 AISIN 3500 for a while and towing heavy.

 

[NIsaacs]

Real world experience is what I am spouting. Don't think too many have the same experiences as me.

Yes, not doubting you at all that 3.42 will work for some people, just not the OP. He has one that he is unsatisfied with. Since the top gear is the same for both trannys, the Aisin is not going to cure his complaint unless he goes lower on the rear axle.

To the OP:

Here is some RPM numbers that are approximate, I am using a 31" tire and don't know the exact size for a dually. These numbers are at 60 mph in 6th gear for all three axle gear choices.

3.42 is 1398 or the bottom of the torque band, any movement of your right foot will cause a down shift or dead pedal.

3.73 is 1521 still on the low side for performance. This gear would work good for me but I tow a lot faster than 60 mph, in general.

4.10 is 1677, rolling hills better look out!

Nick

 

[RVTRKN]

My personal experience with the 3:42, was too low RPM for 50mph in drive @1000 rpm. I would give it a little throttle and it would shudder and ping real bad. I had to manual shift it during low cruising speeds. The advise I got was to keep it in T/H which I didn't like with the 68rfe. If your going to cruise at low speeds at any weight you'll have hunting and possibly what I experienced. Yes, on the open HWY at 70mph, it was nice running low RPM but climbing Cajon pass into the high desert sucked.

 

[Cummins12V98]

Yes, not doubting you at all that 3.42 will work for some people, just not the OP. He has one that he is unsatisfied with. Since the top gear is the same for both trannys, the Aisin is not going to cure his complaint unless he goes lower on the rear axle.

To the OP:

Here is some RPM numbers that are approximate, I am using a 31" tire and don't know the exact size for a dually. These numbers are at 60 mph in 6th gear for all three axle gear choices.

3.42 is 1398 or the bottom of the torque band, any movement of your right foot will cause a down shift or dead pedal.

3.73 is 1521 still on the low side for performance. This gear would work good for me but I tow a lot faster than 60 mph, in general.

4.10 is 1677, rolling hills better look out!

Nick

Your info is accurate i'm sure so please post what you just did with 3.42's in 5th. You will see what I am talking about.

 

[Cummins12V98]

My personal experience with the 3:42, was too low RPM for 50mph in drive @1000 rpm. I would give it a little throttle and it would shudder and ping real bad. I had to manual shift it during low cruising speeds. The advise I got was to keep it in T/H which I didn't like with the 68rfe. If your going to cruise at low speeds at any weight you'll have hunting and possibly what I experienced. Yes, on the open HWY at 70mph, it was nice running low RPM but climbing Cajon pass into the high desert sucked.

There is a reason there is a TH button and you chose not to use it. Pretty simple to touch the gear down rocker and drive it like a manual.

" climbing Cajon pass into the high desert sucked" Well I had ZERO issue towing the same pass with my 28-29K combined as the truck down shifted like it should have and just climbed the hill.

When towing heavy I experimented in leaving it in 6th and down shifting as needed or just leave it in 5th. 5th won! Same as 6th with 4.10's.

 

[NIsaacs]

Your info is accurate i'm sure so please post what you just did with 3.42's in 5th. You will see what I am talking about.

Since you said "please" here it is

68RFE, 3.42's, 5th (0.82) @60 mph, rpm is: 1820

Aisin, 5th (0.77) rpm is: 1710

For an SRW truck with no other choice the 3.42 works, there are likely a million out there. But on a dually you have all sorts of options, why not custom order for your personal preference.

The OP has a '15 3500 3.42 geared truck, he don't like it.....he is a faster learner than you, he is going to dump it after 3 years, it took you 4 years

Nick

 

[Cummins12V98]

Thanks!
If mu 11 had the AISIN I would still be driving it even towing 33-35K. But buying new for my weights I would get 4.10. Under 28K I would get the 3.42's any day.

 

[GBBrown]

Yes, not doubting you at all that 3.42 will work for some people, just not the OP. He has one that he is unsatisfied with. Since the top gear is the same for both trannys, the Aisin is not going to cure his complaint unless he goes lower on the rear axle.

To the OP:

Here is some RPM numbers that are approximate, I am using a 31" tire and don't know the exact size for a dually. These numbers are at 60 mph in 6th gear for all three axle gear choices.

3.42 is 1398 or the bottom of the torque band, any movement of your right foot will cause a down shift or dead pedal.

3.73 is 1521 still on the low side for performance. This gear would work good for me but I tow a lot faster than 60 mph, in general.

4.10 is 1677, rolling hills better look out!

Nick

Thanks NIsaacs...info i was looking for. Speed limit on most roads where i live is 55, so 6th gear is pretty useless with 3.42's. I only pull at 60~65 due to tire ratings and for me thats fast enough. Run alot in 4th and 5th depending on the road, thats why i was asking about lower gearing.

 

[CMB]

Not trying to hi-jack the thread but since we are kinda on the topic:
Would 4.10s in a 2012 SRW be a special factory request or did some come with this gear package? I'm just trying to understand when it sounds like SRW gearing options are limited from the factory.

Thanks!