Low speed loaded test of 3.42....

[AH64ID]

As some of you might recall I've been skeptical of 3.42's and low speed performance for some time. We all know that at speed a truck with 3.42's can downshift and make up the gearing difference to 4.10's. But you can't downshift from 1st...

A couple times a year I pull some long slow dirt/gravel grades loaded up, and my Sep/Oct trip is often the heaviest of the pulls. This year I was right at 24K GCW and the grade is 7 miles long and averages 5%, with the last 3 miles averaging 7% with stretches above 9%... all at 20 mph or less and often in 4wd. So I started at the bottom watching trans temp and TC outlet temp.

I had noticed in the owners manual that it tells you to lock it into 1st at speeds below 20 mph on long grades to reduce trans temp, so I played with this as well.

Here's what I found...

Plenty of power in 1st and 2nd.

The trans would prefer to hold 2nd, so using ERS was the only way to keep it in 1st at those speeds.

Trans sump temps never got above 183°, but when I let the trans do it's own thing (2nd unlocked) the TC outlet temp would get above 220°. When I would then lock it in 1st the rpms were ±2500 and TC outlet temp would drop quickly to 199° and hold... so I stayed in 1st.

Needless to say I was not worried about the temps I saw, and was very happy with the long mostly 1st gear pull.... probably more miles in 1st this weekend than most trucks see in a year.

So my 3.42's are here to stay, and based on what I have seen so far I am surprised that Ram dropped 3.42's... personally I would offer 3.42's or 4.10's, 3.73's are a compromise in most gears and I actually think I would like them less than my 3.42's ALL the time. (another reason I'm glad I didn't get a '19) I'm very happy with the ability to grab 4th at 70 loaded with 3.42's and the empty rpms at 85 too.

On other stretches I found that if the TC is locked in 2nd it will hold down to ±18 mph and has a LOT more torque down there that I expected... I guess that's what extra displacement and a VGT can do for you.

Later in the tow I did find some sections of road that were too steep/rough for 1st to keep the temps below 230° on the TC oulet, still with good sump temps. So I just used 4Lo for those couple short stretches.

I was amazed that I didn't miss my NV5600 once on the entire tow in, thou dad (who has a '17 like my '18) said he missed his '06 G56 on a few of the stretches. He was likely in the 18-19K GCW range.

 

[NIsaacs]

My guess is, you will miss the standard on the return trip. It will be interesting to see what works on the down hill.

 

[AH64ID]

My guess is, you will miss the standard on the return trip. It will be interesting to see what works on the down hill.

The back side of that grade is about the same.

It's not fast enough for TC lock and thus exhaust brake, but keeping it in 1st worked better than I expected and only had to use the service brake for corners similar to the 05. I looked once and the intake plate was down to 39% so there is likely some restriction and helping a little. It's not as good as the manual, but also nothing to complain about.

 

[Wiredawg]

I think for the higher grades, putting into 4Low would work well.

I know the 3.42 guys catch a lot, but no worries. I had a 3.54 00 Ram 2500 6spd QC 4x4 that did pretty good towing heavy. I was SO far over weight ratings except tires and axles that it did struggle starting up hill towing heavy.

Anyhoo, interesting to hear folks driving towing stories.

Happy Trails, Ron

 

[AH64ID]

I think for the higher grades, putting into 4Low would work well.

Yes 4Lo worked quite well when I needed it. I was a little disappointed that it won't lock the TC in 4Lo until 20 mph, like high range, but oh well.

 

[kthaxton]

Sounds like you could benefit from BD's 2 Low kit. I sure love it when I need it.

 

[AH64ID]

Sounds like you could benefit from BD's 2 Low kit. I sure love it when I need it.

I've thought about it, as I used 2 Lo every now and then in my 05 with a spin free kit. On long steep dirt/gravel roads I'm in 4wd most the time anyhow, as I like how it pulls and doesn't slip tires as much.

The time of year where I would use it the most is coming up, so I am going to see how it does or if 4Lo is annoying... it's all dirt, but I still don't like the xcase binding up.

 

[SnoKing]

Another owner in my 3.42 gears are great with the Aisin Club!!! SnoKing

 

[Cummins12V98]

If I were to order a 20 I would have chosen 3.42's even towing the 33-35k combined I do. Of course it would have an AISIN!!!

 

[SnoKing]

Another owner in my 3.42 gears are great with the Aisin Club!!! SnoKing

Fueled at Fry's in Globe Az and drove back to Gold Canyon, it must be down hill most of the way! No I did not drive 29 MPH all the way. Picture was as I turned into the right exit lane to the Park.

 

[Cummins12V98]

Nice!!! Now turn around to your fill up and report back.

 

[HPSimpson]

Maybe 18 or 19 going back to fuel station ?

 

[cerberusiam]

I am surprised that Ram dropped 3.42's...

Not so surprising if you look at from the big picture of an HD truck market. I suspect there is a lot more to the 3.42 story than has ever been exposed. Very few people that bought those trucks to use hard have much good to say about the road gears. In a real HD hard usage scenario it is even a valid discussion point.

Have to be honest here, if you are doing that traverse a couple times per year instead of day after day week after week it isn't really comparable. There is a lot more to consider than the recreational users when targeting these markets.

What route did you take to develop these observations?

 

[SnoKing]

Elevation drop was 3510 to 1778. Which is not the much in 47 miles. Lots of ups and downs on the route however. From Globe you climb to 4518 at Top-of-the-world, Superior is 2888, Miami is 3402, you mush then drop down and and back up to Gonzales Pass at 2631, then you drop into the valley and on to Gold Canyon.

 

[Cummins12V98]

Not so surprising if you look at from the big picture of an HD truck market. I suspect there is a lot more to the 3.42 story than has ever been exposed. Very few people that bought those trucks to use hard have much good to say about the road gears. In a real HD hard usage scenario it is even a valid discussion point.

Have to be honest here, if you are doing that traverse a couple times per year instead of day after day week after week it isn't really comparable. There is a lot more to consider than the recreational users when targeting these markets.

What route did you take to develop these observations?

Have a friend with a 13 DRW AISIN 3.42’s with over 125k. He tows a HEAVY Mobile Suites like I do 34k combined full time.

He loves the 3.42’s!!! Tows 60 at 1,750 rpm in 5th. Hill starts no problem on grade.

I asked would you get the 3.42’s again, yes!

I loved my 3.42’s at 29k combined. Only issue was steep hill starts because it had the 68rfe.

So unless you have towed what I have along with my friend ya just don’t know!

 

[NIsaacs]

So unless you have towed what I have along with my friend ya just don’t know!

I don't recall any complaints about the 3.73 gear from '07-'12....It's not like you and your friend are the only truck drivers here....

 

[Cummins12V98]

I don't recall any complaints about the 3.73 gear from '07-'12....It's not like you and your friend are the only truck drivers here....

Don't think I was responding to 3.73"s. I think "I" explained why "I" loved the 3.42's along with my friend.

 

[SnoKing]

Don't think I was responding to 3.73"s. I think "I" explained why "I" loved the 3.42's along with my friend.

What about me???????????????????????

 

[AH64ID]

Not so surprising if you look at from the big picture of an HD truck market. I suspect there is a lot more to the 3.42 story than has ever been exposed. Very few people that bought those trucks to use hard have much good to say about the road gears. In a real HD hard usage scenario it is even a valid discussion point.

Have to be honest here, if you are doing that traverse a couple times per year instead of day after day week after week it isn't really comparable. There is a lot more to consider than the recreational users when targeting these markets.

What route did you take to develop these observations?

Honestly I can only think about 1 person with really negative comments on 3.42's. I did have plenty of negative preconceived notions about 3.42's but they have all been erased. Sure there can always be complaints, it's impossible to please everyone.

Most people don't tow heavy at 10-15 mph sustained so it's seamless to them at low speed. 3.73's aren't enough lower to get the tq converter to lock at those speeds, and I honestly am not even sure 4.10's are. You will get some benefit from the added mechanical advantage but nothing like being able to lock the torque converter. That's were the 8-10 speeds are going to shine, if they do the ratio's correctly.

All my slow speed stuff is in the middle of Idaho on forest service roads.

My biggest gripe on the 3.73's in the 05 was highway towing. Too many rpms in 5th for 65-70 and not enough in 6th.. that doesn't change with 3.73's and the Aisin just referencing 4th and 5th. 4.10's are enough lower that you can run similar rpms/speeds at one gear higher. This is another place the 8-10 speeds could really do well.

The ratios in Ford's 10 speed are actually awesome for super low speed and interstate towing, and they run a tall rear end too.

So I still am surprised that Ram offers 3.73 and 4.10 as their two choices. 3.42 and 4.10's just seem like a better spread to offer. 3.42's will help with emissions, NVH, and economy over 3.73's.

Just my thoughts and opinion on the gearing.


For any of the 4.10 crowd, @Cummins12V98 @TFucili, what is the lowest speed you have noticed the torque converter lock in 2nd? I can't get mine to lock below 20, but I wonder if that's speed or rpm restricted... or both. The same rpms is 16 mph in a DRW with 4.10's. With my OE SRW tires I'd be doing 17 mph, hardly worth the cost of gearing for 3 mph on tq converter lock and I don't even know if it would lock. The mechanical advantage would help some, but I still don't see a need for it at SRW weights.

 

[SnoKing]

I looked at new SRW RAMs for 3 or 4 years before buying the 2015. Lucky for me they only had 3:42's or I would have bought one with 3:73's. I now know that would have been a mistake. I think the reason RAM dropped the 3:42 is all about the taller 1st and 2nd gears in the 68RFE, and the Aisin transmission'd trucks got swept up in that decision.