Test drove 2013 Ram 3500 today

Hiking Hunter wrote:

RCMAN46 wrote:
Do you mean your speed is varying!

No, the speed is as solid as a rock. What I meant was the throttle slightly increased/decreased to keep the truck as the same speed. But again, this may not be a true problem - it's pretty suttle. Heck, it may have been due to a gusty head wind the first time I noticed it. It's something that I'm going to keep an eye on as I drive the truck. I just don't get it on a flat and level roadway for long enough to evaluate it very often.

And the only reason I mentioned the 3.42 knuckle was because that's where the discussion for this thread had turned, and my earlier posts that the 3.42 seemed fine for me and my towing requirements, and was NOT the cause of any "hunting".

In order for the speed to remain constant there has to be some throttle adjusting. That is what a cruise control does.
Even what appears to be a level road is not all that level.

Hiking Hunter wrote:

RCMAN46 wrote:
Do you mean your speed is varying!

No, the speed is as solid as a rock. What I meant was the throttle slightly increased/decreased to keep the truck as the same speed. But again, this may not be a true problem - it's pretty suttle. Heck, it may have been due to a gusty head wind the first time I noticed it. It's something that I'm going to keep an eye on as I drive the truck. I just don't get it on a flat and level roadway for long enough to evaluate it very often.

And the only reason I mentioned the 3.42 knuckle was because that's where the discussion for this thread had turned, and my earlier posts that the 3.42 seemed fine for me and my towing requirements, and was NOT the cause of any "hunting".

I think you are being way to sensitive to what your truck is doing going down the road. I don't pay that close of attention to mine. I set the cruise and remove foot from accelerator and let it do its thing.

RCMAN46 wrote:
Do you mean your speed is varying!

No, the speed is as solid as a rock. What I meant was the throttle slightly increased/decreased to keep the truck as the same speed. But again, this may not be a true problem - it's pretty suttle. Heck, it may have been due to a gusty head wind the first time I noticed it. It's something that I'm going to keep an eye on as I drive the truck. I just don't get it on a flat and level roadway for long enough to evaluate it very often.

And the only reason I mentioned the 3.42 knuckle was because that's where the discussion for this thread had turned, and my earlier posts that the 3.42 seemed fine for me and my towing requirements, and was NOT the cause of any "hunting".

Hiking Hunter wrote:

Hiking Hunter wrote:
I do notice, though, some "hunting" when using cruise control unloaded on flat and level ground.

I need to elaborate a little on my statement. When I said "hunting" I was referring to the cruise control hunting for the right speed with the accelerator; and then only when on flat and level ground. There is no transmission hunting. I have the 3.42 back end.

Do you mean your speed is varying! If that is the case you may have a defective cruise controller. My 05 chevy Duramax cruise control is solid as a rock. I do not see where a 3.42 axle would have anything to do with this problem.

Hiking Hunter wrote:
I do notice, though, some "hunting" when using cruise control unloaded on flat and level ground.

I need to elaborate a little on my statement. When I said "hunting" I was referring to the cruise control hunting for the right speed with the accelerator; and then only when on flat and level ground. There is no transmission hunting. I have the 3.42 back end.

ib516 wrote:
I think if you get a SRW, 3.42s are your only choice with the diesel. You need to go to a DRW to get 3.73 or 4.10. Much like Ford. 3.31 or 3.55 in SRW trucks.

Yeap, select the 3.73 or 4.10 gears and it forces the build to dual rear wheels. Bummer!!!!! 12,300 GVWR and the wrong gears for really towing a big load. You have a truck with a 4778 payload and 17,300 max trailer load and crappy to tall gears.

Chris

When you all are having gear hunting problems are you using tow haul? With the gm Allison tow haul prevents most gear hunting problems.
With 850 lbs or torque I would think there should not be a problem with a 3.42 gear. There is nothing wrong with towing in 5 th gear. That is the purpose of a transmission.

Vulcaneer wrote:
I just bring this up because my truck runs 1600 RPM at 65 mph in top OD gear. Has 20" wheels/3.55 RAR. And .67 sixth gear OD. According to the torque specs it's peak (850 ft lbs according to the window sticker) is at 1600 RPM. I don't find it hunting gears when towing heavy on minor grades. In my mind I think this is pretty good gearing for heavy towing. Makes cruise control very useable when towing.

If the Ram really does run Rpm @ 72 mph was ~1500, I would like to see a lower RAR gear choice. The Aisin trans is a great unit. The Cummins runs all kinds of torque. But I wonder if the gearing makes best use of the engine trans combination in real world towing situations. I just don't like to hear any tranny hunt. And if using Cruise control, it needs to run at peak torque to be really effective when heavy towing.

Certainly not badmouthing the new Ram. Sound like a really fine truck. I just have this one question is all.

I think part of the hunting problem some talk about is because the torque curve now is not as flat as my 5.9. The curve I saw shows it peaking then falling off some as rpm goes up was not impressed with that part. But them 250 more ft.# than mine is a lot so maybe it evens out by 2600-2800 range.

I've been reading many posts that state the 3.42 ratio can cause a lot of transmission hunting for the right gear even on the slightest of incline, but those 3.42s do seem to give high mpgs though. I just ordered and chose the 3.73s.

I just bring this up because my truck runs 1600 RPM at 65 mph in top OD gear. Has 20" wheels/3.55 RAR. And .67 sixth gear OD. According to the torque specs it's peak (850 ft lbs according to the window sticker) is at 1600 RPM. I don't find it hunting gears when towing heavy on minor grades. In my mind I think this is pretty good gearing for heavy towing. Makes cruise control very useable when towing.

If the Ram really does run Rpm @ 72 mph was ~1500, I would like to see a lower RAR gear choice. The Aisin trans is a great unit. The Cummins runs all kinds of torque. But I wonder if the gearing makes best use of the engine trans combination in real world towing situations. I just don't like to hear any tranny hunt. And if using Cruise control, it needs to run at peak torque to be really effective when heavy towing.

Certainly not badmouthing the new Ram. Sound like a really fine truck. I just have this one question is all.