Forum Discussion
MikeRP wrote:
If you think the 5.7 Hemi is long in the tooth like me then most long in the tooth motor is the Chevy 5.3lL. I know it’s been a good engine and I am not trying to offend anyone and I’ve owned 2 and driven work vehicles with this motor many miles.
But it needs a major update!
Why does is need a major update?
What does it not do what other motors do? :hwilber1 wrote:
ShinerBock wrote:
wilber1 wrote:
Higher RPM's mean more line pressure and less chance of slippage.
The line pressure within the clutch housing is dictated by the valve body and increases pressure within the clutch housing based on engine load/throttle input. Line pressure is one of the things I monitor on my CTS2. I can drop down a gear and be close to max rpm applying the same throttle and the line pressure to the clutches will hardly even change. In contrast, I can be at low rpm going up a hill which requires more throttle and my line pressure at the clutches will jump close to max 225 psi even though my rpm didn't change much.
I should have phrased that differently. If RPM is too low the transmission will not be able to make enough line pressure. This is always an issue with diesels that make huge torque at low rpm.
It would have to be pretty low, because I can make the line pressure in my tuned Ram 2500 CTD go to 200+ psi at just 1,000 rpm. Stock valve body max line pressure for my truck is 170 psi.- I have an ZF 8 speed in my diesel BMW, and yes it still slips between shifts which is more noticeable in comfort mode where it has buttery smooth shifts. When I put the car in sports mode, the shifts become more firm and quicker. Shifting in manual mode they are the quickest to the point where it is almost unregistered on my data logs or app.
Samsonsworld wrote:
wilber1 wrote:
Samsonsworld wrote:
One, I've never seen an engine run at full throttle that didn't get hot. Two, fuel has nothing to do with the tranny. If that torque converter slips, it heats up fast. Also a problem running full throttle.
The ZF torque converter is only unlocked when the truck is stopped and for launch in first gear, otherwise it is locked all the time. If it slips it's because it is broke. Higher RPM's mean more line pressure and less chance of slippage.
Your tranny slips every time you change gears or it would jerk and it will hunt when you have enough throttle.
The 68RFE in my truck does but the ZF in my Audi doesn't. Shifts take place in 200 milliseconds and when it does, the rpm changes are solid with no sign of converter unlock.
Car and DriverShinerBock wrote:
wilber1 wrote:
Higher RPM's mean more line pressure and less chance of slippage.
The line pressure within the clutch housing is dictated by the valve body and increases pressure within the clutch housing based on engine load/throttle input. Line pressure is one of the things I monitor on my CTS2. I can drop down a gear and be close to max rpm applying the same throttle and the line pressure to the clutches will hardly even change. In contrast, I can be at low rpm going up a hill which requires more throttle and my line pressure at the clutches will jump close to max 225 psi even though my rpm didn't change much.
I should have phrased that differently. If RPM is too low the transmission will not be able to make enough line pressure. This is always an issue with diesels that make huge torque at low rpm.- ^What he's saying is the 8hpXX transmissions don't unlock and then noticeably lock the Tq converter in each gear like older transmissions do. I believe it unlocks momentarily, but 99% or whatever of the time it's locked. Although I could be wrong there. The transmissions in the SRTs, at least, (same platform as the other trans's), can rip off shifts in 160mS, or .16 seconds. I'm not sure if the TC unlocks or engine defueling accomplishes the smooth shift.
Lots of grumpy "get off my lawn" type posts. It's entertaing most of the time, but cmon, y'all....you don't have to hate on everything all the time! wilber1 wrote:
Samsonsworld wrote:
One, I've never seen an engine run at full throttle that didn't get hot. Two, fuel has nothing to do with the tranny. If that torque converter slips, it heats up fast. Also a problem running full throttle.
The ZF torque converter is only unlocked when the truck is stopped and for launch in first gear, otherwise it is locked all the time. If it slips it's because it is broke. Higher RPM's mean more line pressure and less chance of slippage.
Your tranny slips every time you change gears or it would jerk and it will hunt when you have enough throttle.wilber1 wrote:
Higher RPM's mean more line pressure and less chance of slippage.
The line pressure within the clutch housing is dictated by the valve body and increases pressure within the clutch housing based on engine load/throttle input. Line pressure is one of the things I monitor on my CTS2. I can drop down a gear and be close to max rpm applying the same throttle and the line pressure to the clutches will hardly even change. In contrast, I can be at low rpm going up a hill which requires more throttle and my line pressure at the clutches will jump close to max 225 psi even though my rpm didn't change much.Sportsmen wrote:
TwoManyToyz wrote:
From 09 to 2015 Dodge put coil springs in the rear of their half ton trucks. That was the turning point for me. At that point i realized
Dodge had no idea what i wanted in a half ton truck. They still dont.
I agree. They are using coil springs to soften up the ride to appeal to the soccer mom crowd. My BIL's 2017 Ram 1500 has a payload of 1148 lbs. Part of that is the coils and the 4X4.... I want leafs in a PU, but they are not marketing 1/2 tons to people like me anymore. In the future only F250's / 2500's for me....
It is not the use of coils, but rather how the coil is designed that makes the difference. They used linear rate coils on the old 1500s and progressive rate coils on the 2500s. Leaf springs with multiple leafs are also progressive rate, but it is much easier to tune a suspension(and use less parts) using leaf springs versus progressive rate coils. So not all coils are the same, and both leafs and coils have their pros/cons.
Linear vs Progressive Rate Suspension Springs- Its daily fare for my 1500 Ram to have a 1,000 to 1,500 pounds between the tongue and bed sometime more. I am at 7,000 GVW often. Love the dramatically better ride road compliance and suspension control of the coil suspension supported dampend and better controlled with axle to frame air bags. The road compliance and control is substantially better than stick and slide harsh and jumpy such as empty bed over expansion joints at one end of the spectrum to sloppy wallowy at the other end of the spectrum of leaf spring suspensions of horse cart days. Plus less NVH (noise vibration harshness) through the coil suspension.
Yes air bags can aid leaf springs as well but they just can't get the ride road compliance and control that you can with the Ram coil suspension. Even semi and straight trucks have largely dumped leaf spring suspensions or went to primarily air controlled what 40 - 50 years ago. The only reason Ford & GM still use leaf springs is because its cheaper and they can get away with it because the general public doesn't know any better. BTW she just turned 500,000 miles no rear suspension repairs. Never a broken leaf or coil rather. Haven't even had any reason to change the rear shocks certainly in part due to the airbags. I do however think Ram should offer air bag assist with the coils as standard or at least as an option. Complete air ride is a different thing and has its own set of pros & cons.
