Dodge-Ford-GM

[HBarlow]

There is something wrong with my transmission, I hitched up a 2000lb (yes, 1 ton) trailer to a brand new truck on the lot and pulled the exact same hill I had just came over with my truck. Cruise set @ 75mph, 6% grade, my truck would drop to about 71mph before it downshifted (yes, it couldn't hold 75mph) If I stepped on the throttle myself, flooring it, the transmission would not downshift.
New truck, cruise set at 75mph, didn't lose speed, didn't need to downshift, HOWEVER when I floored it myself, the transmission immediately downshifted. Salesman was with me and witnessed this.

Even after this, I still can't convince the dealer there is something wrong with my truck. I video'd the way it was shifting pulling the 19,500 load, but it was night and the gauges didn't come through clearly enough to show what it was doing.

So what did you expect? Your dealership is not going to do anything but fumble around reading codes and scratching their heads. If you push hard enough they'll probably screw around with your truck and replace a part or two trying to please you.

You have the wrong gears for towing. 3. 42 differential gearing is the worst possible choice you could make. The poor towing performance you are reporting is not a problem with the high torque/low rpm Cummins engine or the new MOPAR six speed. The engine/transmission combination work great with 4. 10 gears hauling anything you want to pull. My cab and chassis ISB6. 7 rated at only 305hp and 610 torque, does a fine job of pulling my 14,000 lb. fiver.

 

[Powder Extreme]

Ya Harvey, the 3. 42's is what's keeping my transmission from shifting properly, I forgot you're the genius who knows everything... . What you just don't seem to realize is the overall FINAL Drive Ratio is what matters. You can have a 4. 10 in 6th or a 3. 42 in 4th, the final drive and engine RPM will be basically the same (I'm not taking the time to calculate the actual ratios, I hope you can see my point)

What I am saying is my transmission is not shifting like it should. What do I expect? I expect a $57,000 truck to work properly, I guess that's asking to much...

 

[CBlack]

Ya Harvey, the 3. 42's is what's keeping my transmission from shifting properly, I forgot you're the genius who knows everything... . What you just don't seem to realize is the overall FINAL Drive Ratio is what matters. You can have a 4. 10 in 6th or a 3. 42 in 4th, the final drive and engine RPM will be basically the same (I'm not taking the time to calculate the actual ratios, I hope you can see my point)



What I am saying is my transmission is not shifting like it should. What do I expect? I expect a $57,000 truck to work properly, I guess that's asking to much...

Yeah, so no other truck from any other manufacturer has any problems what so ever when you drive them off the lot?



Quit making excuses and get rid of your Ram if you dislike it so much. When your Dmax starts having injector problems, don't come crying about it here.

 

[Powder Extreme]

Sigh... . I'm not making any excuses, I'm simply stating that my Ram isn't working properly. What excuses am I making? As stated, I have already ordered a new truck.

My Ram has been in the shop 5 times in the 6 weeks I've owned it, sorry if I feel that's excessive.

 

[HBarlow]

Ya Harvey, the 3. 42's is what's keeping my transmission from shifting properly, I forgot you're the genius who knows everything... . What you just don't seem to realize is the overall FINAL Drive Ratio is what matters. You can have a 4. 10 in 6th or a 3. 42 in 4th, the final drive and engine RPM will be basically the same (I'm not taking the time to calculate the actual ratios, I hope you can see my point)

What I am saying is my transmission is not shifting like it should. What do I expect? I expect a $57,000 truck to work properly, I guess that's asking to much...

That's a pretty silly argument. Yes, if the truck was actually in 4th gear the gear ratio would perhaps be similar to a 4. 10 geared truck in sixth gear (I haven't looked at the numbers, just accepting your statement).

But I believe you said in an earlier post that you are trying to tow in fully automatic D mode which is programmed for highway cruise and fuel economy, not tow/haul mode or using the paddle shifter to manually downshift it yourself.

Then, even if you did manually downshift to approach the grade in 4th direct, if the load is realy heavy and/or the grade is very steep, you have to force or demand another downshift all the way to 3rd gear.

By comparison, the 4. 10 geared truck would approach the grade with a large gearing advantage and if it shifted down one to 5th, or two gears to 4th direct it will have a huge gearing advantage which means torque multiplication advantage over the 3. 42 gears.

Differential gears are real numbers with real consequences to load launching ability and grade climbing ability while towing.

I'm sorry you don't like your Dodge but it is your fault for selecting 3. 42 gears then trying to tow heavy with it, tow much beyond its rated towing capacity, in the western mountains.

Have you considered what Dodge says in official literature is the maximum towing capacity for your truck? Gary Owens posted it.

I hope you love your Gov't Motors truck.

 

[Powder Extreme]

Yes I did post I was towing in drive, I had a huge heavy trailer weighing one whole ton! No way a truck with 3. 42 could ever manage that much weight. . . Come on man. Get off the 3. 42 is bad high horse. I am not saying a 4. 10 wont tow better. But mine should do much better than it does. Can't even tow 2000lbs up a hill? That's one fifth the capacity dodge rated it for. And yes, I was in tow haul mode but the transmission STILL wouldn't downshift.

 

[67guzzler]

Yes I did post I was towing in drive, I had a huge heavy trailer weighing one whole ton! No way a truck with 3. 42 could ever manage that much weight. . . Come on man. Get off the 3. 42 is bad high horse. I am not saying a 4. 10 wont tow better. But mine should do much better than it does. Can't even tow 2000lbs up a hill? That's one fifth the capacity dodge rated it for. And yes, I was in tow haul mode but the transmission STILL wouldn't downshift.

Yep -- Something isn't right. The ratio is a "red-herring" in this discussion. Hope you get to the bottom of it!

 

[Powder Extreme]

Yep -- Something isn't right. The ratio is a "red-herring" in this discussion. Hope you get to the bottom of it!

Thanks! Im hoping i can convince the dealer it isn't right.

 

[RVTRKN]

Yep -- Something isn't right. The ratio is a "red-herring" in this discussion. Hope you get to the bottom of it!

That is his problem, pulling a grade with the auto in 6th (D) with 3:42 gear will dog any load. Remember in 4th, to equate the same ratio as 4:10 in sixth, is running a lot slower at the higher RPM. But Powder wants to pull in 6th. So lets take out the 3:42 ratio and auto trany and compare it to a manual you must down shift to get to the top of the grade. My C&C with 3:73 G56 pulling 22,000K up the back side (so. bound) of the the Grapevine can do 55 mph top speed and RPM in 4th, so with the 3:73 rear, in 6th, I would be run over in the truck lane, not to mention melt a piston with high EGT. 3:42 gears on these trucks are too tall and you will blow out the gear set a lot sooner. There are times I wished I had 4:10's when I'm towing in California at 55MPH when I encounter a slight grade, which cause me to hunt for the correct RPM.



Powder, I hope you get it resolved, but if you try the same ratio in the other brands, expect the same. I would think an experienced salesman would discourage the ratio if its known it will pull heavy. And yes, I feel my boat at 3K GVW with my 3:73 ratio which cause me to down shift pulling a grade, unless I want to blow my engine due to high EGT.



Here is a pic of the rig that I'm extremely happy with, even with the taller 3:73 ratio I needed to order it with due to city driving in the summer.



Good luck

Steve

 

[Powder Extreme]

The whole point IS that the truck WONT downshift! Certainly when I am towing heavy I lock out higher gears. But with only 2000lbs behind me there is no need to do so. Dodge rated it to tow 10k and that is for the typical person who puts in gear and goes. Im sorry, but if I melt a piston simply by selecting tow haul and putting the transmission in D while towing 1 ton, there's a whole lot more wrong with my truck than I thought. Why wont the transmission downshift automatically? Even flooring it at 1800 rpm it will not downshift. If i manually downshift at 1800 the rpm only goes to 2400 so its certainly in no danger of redlining. How in the hell is it my rear end that's preventing the transmission from downshifting?

 

[Powder Extreme]

You're saying that your truck will pull 22000lbs up the grapevine at 55mph??? That's pretty impressive! You'd have to be grossing at least 30000 probably closer to 31k. And your truck is stock?

 

[RVTRKN]

You're saying that your truck will pull 22000lbs up the grapevine at 55mph??? That's pretty impressive! You'd have to be grossing at least 30000 probably closer to 31k. And your truck is stock?

Thats GCW, and it is stock. Have you ever tried to see what RPM she will down shift at? My boat which is 3K, only a 1K more than your trailer does pull against my truck when climbing and I'll always have it in 5th to keep from lugging.



Do you live near or can you get to Frahm Dodge in Norco Ca? I know the trany expert very well, and I can let him know what problems your experiencing and have him look at it.



Even if your having other issues that are not related to the rear differential, it is still to tall and it will notice the 2K pounds.

 

[Powder Extreme]

Okay, total weight, that makes more sense.

If I let the transmission do it's thing it waits till 17-1800rpm before it will downshift. When I drive it manually shifting, I usually downshift in the 21-2200 range and all is well. I understand 2k will pull it down some, the whole point is that when it does pull it down, the dang transmission won't downshift.

I live in Montana, but used to drive Semi's so I'm very familiar with the Grapevine.

I'm surprised your 20' boat on the trailer is only 3k, my 19' Regal fully fueled with skis etc was closer to 4k on the trailer. *shrug.

 

[HBarlow]

Although you may want the transmission to downshift earlier the ECM/PCM are probably programmed not to until much lower rpm. If you want higher rpm, flip the paddle in the end of the shifter.

The Cummins engine is a long stroke high torque engine that produces maximum torque, 650 lb. ft. in the case of the ISB6. 7 pickup application, from 1500 rpm to 2700 rpm. There is NO NEED or reason for it to downshift before approaching the bottom end of the torque band. Revving it to 2400 rpm will produce more horsepower and stronger acceleration, but not more torque and torque is what you want to pull a grade.

RVTRKN is probably exaggerating or perhaps misinformed when he says he is worried about melting a piston.

The Cummins ISB with OEM programming and components will pull maximum rated capacity at full throttle all day long without exceeding design limits.

With gauges on my previous '06 ISB5. 9, it would reach about 1450* on long hard pulls in high ambient temperature conditions. That is normal and the engine is designed to withstand that for several hundred thousand miles of operation.

My current ISB6. 7 is the derated 305/610 for C&C applications. It rarely reaches 1300* on long hard pulls.

You can't break a factory stock engine doing what it is designed to do. If you install magic black boxes or aftermarket injectors all bets are off and your warranty will be voided.

 

[craiggo]

Couldn't have said it better myself....

I say who cares :-{}. There are a lot of factors when trying to figure out whats best for you. In 04 I test drove each of the big three diesels. Dodge wasn't really on my list. But I decided to stop in and test drive it. I was really impressed with the way it drove and the power it had (last one I test drove was in 01 not impressed then). The ford was to noisy and the chevy I drove was 49K and was nice. So it boiled down to what I liked and could afford.

With this 2010 truck I got to take home (overnight) a 62K Ford F350 diesel. I liked the engine and transmission. But during my normal route home I was throw around on the rough uneven pavement, the front end feel sloppy to me. The Dodge in comparison was a nicer ride and handle felt more car like. I got a lot more for my money at 55K. For me all of these trucks are over kill for the 9K Travel trailer I plan on buying this year. So I bought what I like for my own reasons. Don't worry what may or may not be the best. Cause no matter what you buy, next year something bigger and better will come out. Then you'll be scratching your head wondering if you should have waited a little longer. Happy Trails.

It all boils down to what is best for you and your needs. When it comes to the Ford Power Strokes I think they are really pricing themselves out of the market compared to what you can now get from Dodge/GM. Ford bought back my 6. 0 so Fords were out of the question when I needed a new truck. They didn't even offer to give me a discount on a new one when they took the old one back so I walked out with "their" check.



I seriously considered the GM but couldn't get the bench seat in their "Laramie" model. Now they offer a Denali but still not bench seat so that was a show-stopper. In my case the Dodge was the best choice. Their MyGIG, BackSeat-TV and new interior were the best all around for our needs and I'm glad Cummins didn't add DEF, it's one less thing i have to worry about.



Craig

 

[RVTRKN]

RVTRKN is probably exaggerating or perhaps misinformed when he says he is worried about melting a piston.

Then why did you pay to have a pyro gage installed? And yes you can, but its more critical for me because I chose the RPM to shift at.



I understand that the ECM parameters and design is set up that way, but it can't see the EGT.

 

[HBarlow]

You can choose to believe whatever you wish and operate your truck in any way you choose, that is no concern of mine.

But when you post is here on TDR newer members may read it and believe it and I consider bad information harmful.

Here is a copy of a message I sent to an engineer in Cummins, Inc. several years ago. For obvious reasons, I have redacted his name to protect his anonymity.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

(Addressee's Name Deleted),

Greetings. I Haven't communicated with you for some time. I hope all is well with you.

I know the question I want to ask is not something you are directly involved with and it may not even be fair to ask. I want to ask you first for an informal answer because I'm not sure the Cummins engine engineers will be willing to answer. If you can answer but direct me not to share the info with the TDR membership at all or if you permit me to share the info but direct me to protect the name of the source, I will honor my commitment to do exactly as you direct.

My question is this: What is the maximum exhaust gas temperature a Cummins ISB engine can safely tolerate for sustained operation at full power and full rated load measured with a typical aftermarket pyrometer with the probe installed in the center of the exhaust manifold?

The reason I ask is, as you know, the numbers are continuously batted around on the TDR forums. Some preach that 1300° is the maxiumum allowable temp for sustained operation because, they claim, aluminum pistons can begin melting at 1300°. Others think temps should be kept below that level. Still others claim that the Cummins engine can stand operating at higher temps without incurring damage or that temperatues measured in the exhaust manifold are not necessarily an accurate measure.

I have no facts but I suspect that all Gen II 24 valve HO engines with electronic injection pump and all Gen III HPCR engines will produce EGTs higher than 1300°at full power and maximum rated load.

My 2001 HO/6 speed, with Bosch "275 hp" injectors (I know that engine modifications are anathema to Cummins engineers but my truck is well out of warranty and my risk alone), is occasionally capable of pegging the 1600° pyrometer climbing a grade under full throttle when operating in high summer temperatures. I am frequently forced to back out of the throttle to avoid what I have been told are excessive EGT levels. I regret that I did not have a pyrometer installed before the injectors were installed to establish a baseline EGT but I suspect that all factory stock HO engines produce high EGTs. I'm not an engineer but I do know that in a diesel engine, more power requires more fuel and results in greater heat.

I have read several threads recently indicating that several owners who have installed pyrometers on their factory stock Gen III HPCR engines are reading EGTs in the 1400° to 1500° range at full power. This makes me think that EGTs in this range are a fact of life and to be expected and accepted.

Can you comment on this subject? Any information or advice you can share will be greatly appreciated and whatever level of confidentiality you direct will be maintained.

If you are unable or unwilling to comment I will understand and will still consider you a friend and a valuable asset to TDR members.

 

[HBarlow]

... ..... and here is his reply, again with his name redacted.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Happy holidays! EGT's are always a touchy subject due to differences in measurement locations and differences in the devices used. It's difficult to say what a true upper limit is on EGT for the ISB engine because we don't test it above the "stock" settings. However, I can tell you what we have measured on the latest 2004. 5 and 2005 engine configurations.

MY04. 5/ 325 exhaust temps can be as high as:

Sea Level: 1375 Deg F pre turbo, 1125 Deg F after turbo.
Altitude: 1450 Deg F Pre turbo, 1200 Deg F After turbo.

The above are typical temperatures from development trips. The MY04. 5 product was developed to operate at these temperatures. I have no idea what would happen at temps above these, because they haven't been tested.

I don't mind you sharing these numbers as long as the source remains anonymous. We don't want someone thinking "Cummins approves this temp on my engine because . . . " . This really isn't a guideline or approval or anything, just some results from tests we've conducted on stock engines.

I hope this help answer you question. If you need anything else, let me know!

-(name redacted)

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

This information is obviously several years old and I have not asked about the ISB6. 7 so can't provide exact information regarding the latest engines. I think it is reasonable to assume that current Cummins engines are at least as capable, durable, and using metallurgy as good as the MY04. 5 engines.

 

[Powder Extreme]

Although you may want the transmission to downshift earlier the ECM/PCM are probably programmed not to until much lower rpm. If you want higher rpm, flip the paddle in the end of the shifter.

Harvey, perhaps you missed the part where I said I drove a new truck off the lot towing my trailer up the exact same grade. Although the new truck didn't "need" to downshift, when I floored it, it WOULD downshift. My truck will not down shift even though it "needs" to to maintain speed...



I seriously doubt the PCM is programmed to lug the truck down to that low of an RPM, in fact a simple test would be for every one of you guys driving an automatic, go out and try it. Get your RPM around 18-1900 in top gear and floor it, let's see how many actually downshift. I'm betting they all will, just like the new one off the lot did. MY truck WONT. That's the problem... .

 

[Deleted member 995608]

This is exactly why I buy manual transmission's. I never did and still don't trust electronics to think for me.