JDeere5105

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

coolbreeze

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

Spooler

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.

JDeere5105

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

Jason

Pooter

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.

sewman

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.

Hounddog

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.

ciamcoop

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.

SpinEmNSmokeEm

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.

ddestruel

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.



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

Hounddog

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.

ddestruel

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.....

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

MikeyB

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

RAMRODD

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.

beretzs

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