08 6spd and 3.42 rear
 

Anyone got an 08 6spd with a 3.42 yet? Just wanted to see if the mileage was better and ran out like it should on the highway.

Thanks

Jason

Don't think you can get 3:42. Only 4:10 or 3:73.

Yes, you can get 3.42 gears with a 6 speed manual tranny. With a manual your choices are 3.42 or 3.73. With the auto your choices are 3.73 or 4.10.

I saw it as an option on some of the 2500's and just wondered.

Jason

I couldnt tell you one way or the other about fuel mileage, but IMO if you are going to be towing heavy or plan on getting larger tires in the future id stick with the 3.73s, if not 3.42s might work out fine for you.

I hve a 98 180HP w/a auto & use it mainly f/towing 6-8000lbs it has a 3.55 gear w/taller tires that end up w/a 3.41 ratio & I don't have any problems other than it slows me down alittle in the mountains.
So if I were getting a new truck I'd go with the 3.42 gears & w/a 6 speed you can always drop to 5th as needed.

Slows you down a little in the mountains? I've towed with that combo and had a friend with that combo in a 02.It wasn't a little slow down in the mountains it was a LOT. If you slowed for anything on a hill towing all you could do until a flat and level or downhill was maintain 45 or 50 mph etc.That gear stinks for towing much of anything.I swapped mine to 4.10s and he traded his off for one with 4.10s. Chrysler wanted to get rid of the 3.55 gear way back when but Dana had no 3.73 only a 4.10 as a option. Heck just save a bunch of money if wanting 3.42 gear and get it with a Hemi.

The older ones slowed down because they have a 100 less horsepower than these new ones. I wish they would have had the option for 3.42's when I bought my 07. If you're towing anything with any weight to it you're going to have to downshift anyway. My first travel trailer weighed 6000lbs, this new one weighs 9000lbs and the truck still pulls them the same. Overdrive on the flat ground and rollong hills, 5th in the mountain passes. Once you're in 5th it will rev it all the way out on a 6% grade. Almost 80mph is fast enough. So I think if you drive over 70 I would opt for the 3.42's.

my '01 had 3:55's and I pulled 15,000-20,000 with it and a good hill (no mountains here) I might have to down shift to 5th if I was under 70 mph.

nothing like over gearing a diesel. turbos need to be loaded up ive run 4.10's and ive run 3.73's and ive run 3.54's with 12v's and all ove my truck swere used to haul GN's with 16k-20k lbs loads the 3.54s were an excellent combo direct was perfect for pulling the hills at any speed i wanted.

if you are using 4.10s you are tacking out the motor and using rpms instead of the turbo to do the work. and on top of that you are sacrificing mileage.


FYI i ran either 285's or 315's for my tires. 100 extra hp help but no matter these motors love low speed gears


And 3.73's have been available for Dana 80's, Dana 60's and dana 70's since Way back in 1992 and before for the dana 70 and dana 60. the reason for the low gears were that they worked very well reason they were discontinued is that AAM didnt offer a 3.42 at the time for the 11.5 axle.
[duhhh]


The arguement for higher gears is a mute one when discussing the cummins. its been proven on paper and in the field for years. if 4.10's are so great for hauling why do so many hotshots opt for 3.73's or back in the day they opted for 3.54's? and if 3.54's sucked so bad and they eliminated them for 3.73's (a 100 rpm jump) why then did they spend all the money re-developing a 3.42 gear set 4 years later? last i checked they dont design out trucks as commuters though the high speed gears do help improve the empty mileage

Nothing like making the sweet spot RPM wise for it to be good at 75 plus mph which stinks.You must have had trucks with some magical h.p.tune to tow that kind of weight with THAT gearing and say it was comfertable to pull with cause mine sucked.Felt like you wanted to put a leg out on inclines and help push.Guess thats why Ford even offers a 4.30 gear in 2500/3500 and 4.88 in the 450/550.They are also bring back the 3.55 range of gear for folks who don't own one of these trucks for what its designed for.

actually own 3 f550's they are great with a gear vendor OD otherwise they cant pull anything but od over 50mph. nothing like pulling a hill in od all the time excellent way to burn a tranny i suspect you may have had another problem but what do i know i've only been towing with them since 89.....[duhhh]

another thought on the dana 135 the only gear ratio available was 4.88's, i often suspect that is to make up for the lack of.... that the std motors in that chassis have... a interesting case study of that is Rick Newland in CA who has a 06 f550 that started life with a 6.0 and a6spd towing a GCVW of 42000 lbs, chipped and all he gripped about the lack of torque and lack of the ability to down shift and take advantage of anyother gear on a grade without loosing speed. the 6.0 was a major disapointment he installed a gen 2 24v nv5600 and a set of twins..... along with a gear vendor od. without the gear vendor the truck was tacked out way too soon all he could use was OD. he searched high and low for taller gears for that diff. he has talked to numerous machine shops about making a custom set of higher speed gears. those 4.88's work great witha ford V-10, they are marginal with a 6.0 and flat suck with a 5.9 and a little power and no gearing to capitalize on it with.
check out diesel power awhile after he built it they did an article on it. he's currently putting a common rail in now to replace the vp44 motor.. its an animal



my trucks it must be that magic that the screw driver and a grinding wheel provides.....

feel free to drop in i'll gladly take you for a ride.

FYI. 315s at 70 mph and 3.73's are 1800 rpm seems perfect to me. direct tows at 2200 save the OD and keep the tranny oil temps down in my 6spds .... i dont like using od on hills you must. out west hills at 65mph are legal but grades are 7-8% . OD and 4.10s require downshifting since if you try pulling hte grade in OD your asking to heat things up, temp gauge in tranny will lety you know when. downshifting with 4.10s is like hitting the brakes so that you arent pulling 3000 up the grade...


when i tow i use direct from 50 mph to 70 mph on the grades and then i still have OD to drop my rpms when i hit a flat.


its all magic i tell you, thats why so many of us do it.

Cheers

I figure with the 3.42 it makes 5th gear (1:1) a much better towing gear. 6th OD is pretty much for cruising unloaded or towing on level ground.

MikeyB

X2 on this ^^^^
My truck pulls the hills better with my 22.5 then it did with the stock tires because of the lower RPMS. If 3.42 gears were a option when I got my 06 No question I would have had them. And then I wouldn't have had to get the 22.5's so I could drive the speed limit.

Someone needs to jot down the RPM's at different speeds using KLENGERS ratio database, that way we will have some real numbers to work with.. Scotty

So here is a chart that shows RPM's.. .Everything in red is either above 2900rpms or below 1600 (since there is no point in cruising above 2900 or below 1600). Rpm's are based off the listed ratios and OEM 265/70/17 Tires.

http://i79.photobucket.com/albums/j1...enHunter_6.jpg

Don't quite follow the above chart but.....
like 'Sewman' said .....

With 35" tires on my 3.55 rear end, I figured once I'm actually at 3.42..... if memory serves?
Lot's of us are! Gives 2000 rpm at 80 mph and works well!
Tows well up to say 12,000 lbs. on my automatic. With a 6 speed I know several that tow heavy and have no concerns.

RJ

Shows RPMs in a gear at a speed, even if the truck cant do it... like you can't go 80 in 1st... but if you did you would be at 21835rpms with 3.73s.


If you have 3.73s and 265/70/17 stock this is what tires does to your effective ratio.. using OEM and toyo rev/mile specs... each tire is a little different, but you get the idea.

285/70/17 : 3.605
285/75/17 : 3.481
325/70/17 : 3.378

With 35 BFG's and 3.55's you actually closer to 3.262 if your truck came with 265/75/16, 3.128 if your truck came with 245/75/16 or 3.252 if your truck came with 235/85/16...

figured using a NV5600 transmission which aside from the 05/06/07 G56 with the high OD the new 07 and later G56 shares similar ratios to the nv5600 so i just used a nv5600 to calculate[guitar]

315/70/R17 35" tire 4.10 gears

55 mph 65 mph 75 mph
4th gear 3065 3622 4179
5th gear 2205 2606 3007
6th gear 1610 1902 2195




315/70/R17 35" tire 3.73 gears

55 mph 65 mph 75 mph
4th gear 2769 3272 3776
5th gear 1992 2354 2716
6th gear 1454 1719 1983


315/70 r17 35" tire 3.54
55 mph 65 mph 75 mph
4th gear 2557 3021 3486
5th gear 1839 2174 2508
6th gear 1343 1587 1831



315/70 r17 35" tire 3.42
55 mph 65 mph 75 mph
4th gear 2646 3127 3609
5th gear 1904 2250 2596
6th gear 1390 1642 1895



285/70/R17 33" tire 4.10 gears

55 mph 65 mph 75 mph
4th gear 3220 3805 4391
5th gear 2316 2738 3159
6th gear 1691 1998 2306




285/70/R17 33" tire 3.73 gears

55 mph 65 mph 75 mph
4th gear 2929 3462 3994
5th gear 2107 2491 2847
6th gear 1538 1818 2098


285/70 r17 33" tire 3.54
55 mph 65 mph 75 mph
4th gear 2780 3286 3791
5th gear 2000 2364 2727
6th gear 1460 1726 1991



285/70 r17 33" tire 3.42
55 mph 65 mph 75 mph
4th gear 2686 3174 3663
5th gear 1932 2284 2635
6th gear 1411 1667 1923


hope that helps

Ok, I'm at 3.26! Thanks :)
So, to answer original question... 3.42 should not be a problem, if towing.... and with smaller tires, should aid mileage, IMO :)

RJ

Wasn't being a dick... just had the calculator built in excell so I ran it :D

Yeah you should be ok towing.. .thou it will drop your tow rating by 1K lbs to get the 3.42's... Personally i would take the 3.73's and add a GV over/under drive if you really want mpgs and good towing... gives you 11 fwd gears (really 10 since 5th over and 6th are very close on a NV5600 and even closer on a G56)....

But look at these numbers.. speeds based on 2200 rpms (CR sweet spot)...

http://i79.photobucket.com/albums/j1...enHunter_9.jpg

And with the gear vendors if you shift at 2200 rpms will be greater than 1600 in the next gear, on every shift (except 1-2)... W/out the GV you have to shift at 2700 to get all the shifts above 1600.


You also have to think about using the EB... with 3.42's your going faster in each gear at max retarding hp... another vote for the GV... look at how many speeds you can choose from, or downshift at with the GV...

http://i79.photobucket.com/albums/j1...nHunter_10.jpg


The only drawback to the GV is the cost... but if you plan to keep the tuck for a long time it will pay for itself.

3.42's all the away.. thats what i would order with a new truck order... my '92 has a 5spd and i am swapping a '07 G56 in it and I run 3.07 gears its great plows greta towes awesome.. out pulls my friends '01 3500 6spd ho with 4.10's, and my dads '02 355 auto..etc.. and i run 285 tires so my effective final ratio is even lower then the 3.07s..etc..
I'm seriously thinking of a third gen manual...a mega cab 5500 4wd 6spd manual would be perfect for me.. but no mega cab in a 5500 with out doing soem parts swapping from a wrecked truck..when i pay some debts off.. if the truck i find doesn't have 3.42s i'm gonna buy teh r&P sets and swap them in etc.. its worth it that much to me...
Later
Deo

The Gear Vendors is an excellent choice for higher gearing/lowering RPM. BUT...is not reccomended by gear vendors, to be used in a towing/heavy load situation (see gear vendors website). I changed out my 3.73's for 3.42's 25,000 miles ago and am very happy. I have the stock tire size and have noticed a reduction of about 175 rpm at 75 mph.

One other thing to take into consideration is where the torque curve is on the cummins motor. I remember the ford 6.0 reached max torque at around 3500 rpm (hence the need for the lower gear ratio). I can't recall but im sure someone will note that the cummins makes all its torque between 1600-1900 rpm. The 3.42 gears in 6th (g56) put me right above it at 75-80 mph.

Just some food for thought.

Please show me where it says not to tow heavy loads with it... everything I find is the opposite...

IMO 189rpms at 75mph just isnt worth the cost..

don't think you can get a 08 with 3.73 anymore.. all 4.10. That's the only option when I ordered mine

just checked again. You can't get the 3.73 with the new 68rfe Auto. So I guess only 4.10

Yeah the website says that, but they are on the lots???

ahh.. I think those are left overs from when they where offering 3.73's. So I think this is a recent change.

Gear Vendors Website
 

Check under "commercial towing" on the Gear Vendors website. It will also explain about a +/- gain in fuel economy while towing.

Like lots of others on here I used to gross 32000lbs + with a NV 4500, 265's 3.54s and other than off the line they were great. I can't imagine getting the 4.10's in anything I was going to pull on the highway there's no need.

Well I guess my neighbor and I have had some SICK trucks cause most miserable pulling he and I both have done is with 3.54 3.55 gear in these trucks pulling anything over 8k.Its all you can do to maintain on grades and if anybody pulls in front of you then its 50 or so mph until the flat/level or downhill.Now pulling through Florida or Texas they work ok not great but ok.Any kind of long uphill pulls unless your floored and running 75 mph that gear not worth a plug nickel for pulling.Thats a hiway CRUISE gear not a working gear.

Hounddog, could you expand on the highway cruise gear comment? Are you referring to a 5 or 6 speed trans (late 01 had nv5600 with a 6speed)?

Granted the older NV 4500 had some trouble with 5th "popping off". But for the most part I used and still use 5th in the NV 4500's and 6th in the NV/G56 trans with no problems.

I currently gross 25-30,000 lbs using 6th gear on the highway at 75-80 (legal speed limit) with no problems at all.

Although I do not own a newer Dodge (wish I could afford one!), I thought that this was interesting. I have had experience with 4.10 gears, but they are not in a Dodge pickup.

They are in my father's 98 Chevy 3/4 ton 4X4 with the 350 Vortec and a five speed. Not exactly the low rpm torque monster that a Cummins is! Also, he owns an 89 GMC 3/4 ton 4X4 with a 350 and the 5-speed and 3.42 gears. Also not a torque rich motor. I can tell you with confidence that the only, THE ONLY thing that the 4.10 gears do is make the 98 pickup slower and cause it to drink more gas. We tow 12,000 lbs with these pickups on a regular basis and the 89 keeps right up with the 98. 4.10s might be a little bit easier on the clutch, but my dad always starts the 98 in second gear, so it really doesn't matter anyway![duhhh] I should add that 3.42s are not the ideal gear ratio behind a 350 engine (3.73s are probably about right), but I would still take them over over 4.10s any day of the week.

My Dodge pickups, as well as most of them that I have used, have 3.54 or 3.73 gears and I couldn't imagine why someone would want 4.10s?????? The only practical reason would be if the rig has large tires and needs to be geared down.

3.42s with the 6-speed should be a sweet combination!:cool: Its good to hear that they finally offer them!

Nothing surprising there, thats for commercial use, or HD recreational use... 25K GVW is above the GVWR of the truck... by almost 20% on my truck..... so it probably has a higher rating than the 3.42's, as they are part of the GVWR, which is only 19K on a 3.42 equipped rig, so the GV has a 25% higher rating than the truck does... should be plenty.

SO for 99% of users the GV will be more than plenty.. and give better mileage when not towing(probably better than 3.42's), and more gear options so better hill climbing when towing.. .something the 3.42's cant do.

IMO the GV is a better bang for the buck... 3.42's drop the tow rating by 1K, as well as drop the GVWR by 1K (2500) or 2K (3500 SRW).. the GV doesnt affect it. 3.42's are only 8% better, while the GV is 22%, and gives you 10 speeds.

My comments were not about what trans but what rear axel gear.Towing with 3.55 gear in the Midwest or Northern states is a struggle.The 3.55 ratio is a travelin/hiway gear not a pulling big weight gear.Chrysler has known that for years and wanted to do away with it way back when but couldn't because of Dana. I changed many a 3.55 geared truck over to 4.10s because sales people told a customer Oh it will pull just fine the way it is.Also I will not tow anything at 75/80 mph! Period.Too darn dangerous.70 is my MAX speed and the 3.55 gears won't do at 65/68 mph.

Mine's an 07 6.7 auto with a 6 spd auto and at 70 mph it tachs 2000 rpm's.before the g-30 recall = 11.2 around town 15.5 highway. After recall 13.2 in town and 17 on the highway.My friend has a 06 5.9 with a manual and 410's and when he's on the highway it screams at 65 mph, he also takes off in third gear 1rst is useless unless your extreem weight.

I agree that 4.10 is a good gear for towing, as long as it's behind a gas engine that makes its power at 3000 rpm. On my 12 valve equipped truck that has its "sweet spot" at 1800-2000 rpm, I'm very happy with my 3.55gears, pulling heavy, whether going up hills or not.

What is heavy and what to you call a hill? Why do you think they even offer 4.10s? Why is it even on a late model there is a warning and disclosers about towing any kind of weight with 3.42s and lots more h.p. then those older trucks with 3.55s had.Wonder why there is a differance in GVWR between 3.55 and 4.10s[duhhh]

no offense, but your friend doesnt have 4.10s w./ his manual they didnt offer it unless its aftermarket, they only offered 3.73 w/ the g56. [dummy]

This is not true (not on your part, but on Chrysler's) Dana Corp. has had 3.73 gears since the early 90s for the D80 and even earlier for the D60 and D70 rear and d60 front