6.4 Truck engine

[CMV157]

As for the limited speed towing uphill, it seemed some of the earlier models would pull power when a certain parameter was reached (such as oil or transmission temp) but I haven't heard of that anymore. Just this year I towed 10k up the ike gauntlet TFL truck uses. I decided to let it ride at 45 mph and although there wasn't a ton of power in reserve unless I revved to the moon, it maintained that speed with rpms in the 3000-4000 range which is impressive. I've had two 6.4s, one with the 6 speed and my current has the ZF 8 speed. A world of difference and confidence in longevity. The extra ratios help it immensely with climbing.

As for oil I've mentioned this in previous posts. I experimented greatly with my last truck and found the absolute best result for all the symptoms the hemi can have is PUP 0w40 with a mopar filter changed at 5k or 1 year.

 

[HEMIMANN]

Why when you can explain it to me after my uninformed post?

Because there are pages of detail to the explanation.

 

[rosco11]

Looking at reviews on line I saw a recent video that stated the 6.4 MDS engine is not put in the 2500 RAM trucks. Is this true? On another video a talking head stated that on the gas engines, when towing, you are limited/governed to 35MPH going uphill. I've not seen reference to these before so would like to know if true.

In other news, I sat in a 2023 Laramie yesterday and really like the improved leather seats. The 2014 models I tried were not comfortable to me so I bought upgraded cloth in a Big Horn edition with a Cummins. Then sat in a 2023 Limited and there were so many switches and gadgets I thought I was in the cockpit of a 747. Really like the RAM but no 6.4 on the lot to test drive. Would appreciate the answer from those who have them to my questions above.

The 6.4 they put into trucks, and they do, is not the same as the 6.4 they put into scat packs. The scat pack engines have more hp, but the torque is close to the same.

A 6.4 in a 6000lb truck is going to get maybe 8 to 9 mpg in the city, my scat pack gets about 11 to 12 in the city. you do not want one in a truck. Get the cummins. Even the non turbo cummins will out pull a 6.4 in a truck and get significanty better millage.

 

[ramffml]

Why when you can explain it to me after my uninformed post?

Couple main points:
- 0w-X vs 5w-X in general is mainly a winter rating difference, how cold can the oil get and still flow. In summer months its irrelevant.
- redline (brand) is chosen because it helps mitigate tick (hemi lifter failures)
- redline 5w-30 in particular seems to have the most effect at reducing tick based on user feedback. Other redline weights work too, but the 5w-30 seems to be particularly good.
- redline 5w-30 is almost as thick as some 0w-40 weights. actual viscosity is not equivalent to 30w or 40w which are ranges.
- 5w-30 redline is more shear stable than many 0w-40 oils, meaning, as the oil is used over 5000+ miles, redline 5w-30 stays thicker than some 0w-40's which shear down and become thinner.

I'm sure I'm missing stuff but that should be a good start.

 

[Mike Wenrich]

With the different brands and weights, is there a difference in oil pressure when switching from what RAM put in when new? I don't believe I saw any reference to that.

 

[ramffml]

With the different brands and weights, is there a difference in oil pressure when switching from what RAM put in when new? I don't believe I saw any reference to that.

Both oil weight and oil filter can change the PSI. I've never changed just the brand all by itself. My idle psi was (stock) about 29 to 30, and now it's closer to 40/41.

 

[Lsujker]

Couple main points:
- 0w-X vs 5w-X in general is mainly a winter rating difference, how cold can the oil get and still flow. In summer months its irrelevant.
- redline (brand) is chosen because it helps mitigate tick (hemi lifter failures)
- redline 5w-30 in particular seems to have the most effect at reducing tick based on user feedback. Other redline weights work too, but the 5w-30 seems to be particularly good.
- redline 5w-30 is almost as thick as some 0w-40 weights. actual viscosity is not equivalent to 30w or 40w which are ranges.
- 5w-30 redline is more shear stable than many 0w-40 oils, meaning, as the oil is used over 5000+ miles, redline 5w-30 stays thicker than some 0w-40's which shear down and become thinner.

I'm sure I'm missing stuff but that should be a good start.

This brings up questions.
First the winter rating. Assuming the line is drawn at -30 deg C that shuts down flow for a designated rate. Must have a gradual flow to stall. We have scientific studies evaluating this not perfored by redline?
Second, does redline reduce tick on an already ticking motor? What happened or lack of maintenance leading up?
Third would be redlines marketing. If it thinner cold and thicker hot, why not market to the weight.

Not discrediting redline (or royal purple) quality. I used it in my manual transmissions and transfer cases. probably is the best. Actually the reason I began using redline, jeep recommends putting conventional 5w30 motor oil in the AX15 5 speed with syncros. GL5 is not recommended for the softer metals.

Sounds like I'm contradicting myself. Usually people who are concerned about a particular oil are also particular about maintenance. Not 100% convinced redline at a different weight is better than pensoil ultra with shorter change intervals on the 6.4. Will do some reading though.

 

[Dusty]

Would highly recommend not using 5w30 in the 6.4. Manual specifically states 0w40. Assuming Ram spec'ed a 0 weight oil at startup for a reason. But like you i stick with pensoil ultra every 5k miles. It will tick for 3 seconds on startup sometimes. So did almost all other modern vehicles I have owned.

My 6 speed runs at 169 deg. max when towing on 35" tall tires. If she goes, its not due to heat. The 1500 ZF runs 10 to 15 deg hotter with no load. Wonder what others have experienced.

I've dragged my 6900 lb. trailer and tractor three times this year (so far) for 250 miles, and even on the hills the 8-speed transmission temperature has never exceeded 184F in the summertime.

Depending on how far I drive, my no load driving has never yielded anything over 169F.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 97173 miles.

 

[ramffml]

This brings up questions.
First the winter rating. Assuming the line is drawn at -30 deg C that shuts down flow for a designated rate. Must have a gradual flow to stall. We have scientific studies evaluating this not perfored by redline?
Second, does redline reduce tick on an already ticking motor? What happened or lack of maintenance leading up?
Third would be redlines marketing. If it thinner cold and thicker hot, why not market to the weight.

Not discrediting redline (or royal purple) quality. I used it in my manual transmissions and transfer cases. probably is the best. Actually the reason I began using redline, jeep recommends putting conventional 5w30 motor oil in the AX15 5 speed with syncros. GL5 is not recommended for the softer metals.

Sounds like I'm contradicting myself. Usually people who are concerned about a particular oil are also particular about maintenance. Not 100% convinced redline at a different weight is better than pensoil ultra with shorter change intervals on the 6.4. Will do some reading though.

Yes it can reduce tick on an already ticking motor. This isn't anything to do with marketing, there is a standard which oil formulators must follow in order to classify 0w or 5w. 0w-40 is more of a range; you will have different viscositys inside that range. But again, some oils don't shear down much (or at all in the case of HPL no vii) throughout their lifetime; they stay "in grade".

I'm far from an expert, you really should read the syn thread or BITOG if you want a better understanding.

 

[PJ Snyder]

Looking at reviews on line I saw a recent video that stated the 6.4 MDS engine is not put in the 2500 RAM trucks. Is this true? On another video a talking head stated that on the gas engines, when towing, you are limited/governed to 35MPH going uphill. I've not seen reference to these before so would like to know if true.

In other news, I sat in a 2023 Laramie yesterday and really like the improved leather seats. The 2014 models I tried were not comfortable to me so I bought upgraded cloth in a Big Horn edition with a Cummins. Then sat in a 2023 Limited and there were so many switches and gadgets I thought I was in the cockpit of a 747. Really like the RAM but no 6.4 on the lot to test drive. Would appreciate the answer from those who have them to my questions above.

The 6.4 Hemi is not available in 2023 for the Ram 2500 Limited. Only the Cummins diesel is available.