Greetings,

New member here with a question.

I purchased a 2005 Ram 1500 QC with 4.7l and 6 speed manual trans, towing package (hitch, wiring, hd battery, 3.92rear, anti spin dif). This past weekend we towed a travel trailer aprox. 4000 - 4500 lbs counting people, fuel, water, gear, etc.

220 mile trip one way, 102 degrees with pretty steady head wind, ran AC all the way. 6th gear was not an option as it would bog down and loose speed/rps, 5th would run at 60-65mph @ 2600-2800rpm. This was for about 2 hour intervals. Is this rpm range, extend travel too hard on the engine? Is it hard on the 6 speed manual trans?

I called the dealer monday and the mechanic said that the 6th gear was basically an overdrive and that running in 5th would be fine while towing. Is there anything I need to consider if I am going to do this? Probably pull the trailer 3000 mile or less per year.

I think this trans is a getrag 238 (sp) and 5th gear is a 1 ratio and 6th is a .79 ratio.


regards

3T

 

mine with the auto works best in the 3000-3500 range. Counting the slip of my torque converter, I would think your 5th would be fine as long as it is a true pulling gear.

 

No problem with those RPM's. Just be sure to take care of the motor oil and change it at appropriate intervals.

 

Thanks stump_breaker and osteodoc08.

Stump_breaker, what exactly do you mean by "a true pulling gear". Pretty new to this stuff and I have a lot to learn[]

regards

3T

 

2600-2800 rpm is not too bad, especially when you consider the shorter crankshaft stroke of the 4.7L V8.

But it is relative.

An engine running continuously at 2800 rpm
will wear out its piston rings
(2800/1800) times (2800/1800) times (2800/1800)
= 3.76
times faster than an engine 'loafing along' at 1800 rpm

If you ran ten 4.7L at 75% throttle at 1800 rpm continuously on dynos my guess is that the average engine would go the equivalent of 250,000 miles before breaking - about 5500 hours

If you ran ten 4.7L at 75% throttle at 2800 rpm continuously the average engine might only last
5500/3.76 = 1460 hours

Neil Young wrote: Rust never sleeps
You could equally say truthfully: Friction never fails to pick your pocket

 

in other words, not an overdrive gear. In my 5 speed auto, the first three gears are pulling gears while 4th and 5th are OD gears although with the tow/haul option selected it puts the truck in 4th. Usually a pulling gear will not be more than a 1:1 ratio. Of course, GM, Dodge and Ford all say you can pull in OD now. As long as they want to pay for the transmission rebuild, they can say what they want.
I think you will be fine in 5th gear but as soon as you feel the truck struggling a little, pull it into 4th. I'm sure someone can chime in with the 6 spd gear ratios.

 

Stump_breaker,

This is from a "press release" I found on the web from the folks at Dodge.

The 1500 will also gain a Getrag 6 speed manual, this is the model 238
used with the 3.7 V6 and 4.7 V8 (no manual offered with the 1500 Hemi)

1st - 4.23
2nd - 2.53
3rd - 1.67
4th - 1.23
5th - 1.00
6th - 0.79
Rev - 3.84

HankL

Thanks for all the detail, I hope to only be pulling a few thousand miles per year.

Osteodoc08 reminded about the oil changes, any other service related items to pay extra attention to on a towing vehicle?

regards

3T

 

Earlier there was a post either here or on another forum by a Ram owner who complained his 6 speed Getrag 238 was a bit 'notchy' and stiff in shifts.

During the course of the discussion someone remarked that BMW uses a lot of Getrags and specifies a different transmission lube than DCx does. If I remember right this guy went and got the BMW trans lube oil and reported back that it gave better shifting feel - but was expensive. After all, BMW does stand for 'Bankrupted My Wallet'

 

Make sure you run FULL synthetic and change it every 4000-5000 miles and you will NOT have any issues. Friction never sleeps as HankL pointed out... but Full Synthetic is a sleeping pill for friction, it will not STOP friction but it slows it down DRASTICALY!

I have witness how useing full synthetic can PREVENT a new rebuilt engine to NOT break in... at all! Talk to any engine builder and they will all tell you NOT to use full synthetic in your NEW rebuilt engine for the first 500-1,000 miles... Break in of the rings is important for a good piston ring to bore seal. If you use synthetics your rings will NOT break in and they will NOT seal!

I personaly do not feel your going to hurt your 4.7L at 3,000 RPMs if your useing a full synthetic oil. I use Mobil1, I get it at WallMart in 5qt jugs. I also use the FRAM HP-1 Race filter (AUTO ZONE) this thing is a monster and will hold nearly an additional qt. Also the flow holes an it are HUGE... the larger holes will help high RPM oil flow. (Please no post on the oil filter study.... This tread is about towing not oil filters)

I hope this helps. ALso You may find that a set of 4.56's may make your 6th gear a useable towing gear...

You have the 3.92 now:
.79 x 3.92= 3.09

65MPH x 3.09 x 336 / 32(TIRE HIGHT) = 2108RPMS



And this is what your doing when you have to put it into 5th with your current set up:
1.00 x 3.92= 3.92

65MPH x 3.92 x 336 / 32(TIRE HIGHT) = 2675RPMS


with the 4.56's it would be in 6th gear:

.79 x 4.56 = 3.60

65MPH x 3.60 x 336 / 32(TIRE HIGHT) = 2457RPMS

So it looks like the 4.56's would be an option if you wanted to use your 6th gear for towing... You would gain only 349RPMs at 65MPH...


Your first gear would be quick:
4.23 x 4.56 = 19.288

29MPH x 19.288 x 336 / 32(TIRE HIGHT) = 5873

And by the math it wouldnt be so bad... it would be a quick shift if you where WOT trying to race... doable with good traction.... but for normal driving they would just get you to the next gear sooner which would lead to increased fuel economey around town...

I would sugest the gears, they will keep you at a lower RPM in the 6th gear and they will also keep your transmission happy as the LOAD/STRESS/Mechanical advantage would be moved from the transmission to the rear end. This equates to a cooler transmission.

SPEED SAFE, AIR RAM

 

Thanks Air Ram

Lots of great info in you reply. The oil is still what the factory put in, only have 500 miles on the truck. I will be going with the synthetic when changing. The truck has 99500 miles left on the extended bumper to bumper warranty so I am not sure how they would take to me having the rear end changed out at this point but it is a good suggestion. 75% of my driving will be highway with no load so the 3.92 will work great for the majority of the time. Sounds like when towing our trailer 5th gear and keeping between 55 and 65 mph will not give us any heartache.

Thanks again for the info.

regards