Chrysler 300 - The Saga Continues

[perryg114]

I would do research on the head problems for this model and see if the engine can be made reliable. Many times it is a case of redesigning the head gasket. If the problem can be fixed, you might be able to tow with it. Using a scan gauge is a great idea. I was able to program mine to display slip ratio which tells you that the torque converter is not locked and you are generating a ton of heat. You can boil the fluid in a big truck transmission if you push too hard with that torque converter slipping. Usually, you lock the transmission in a lower gear or just back off. HP is never the problem but how long you can run at max HP. Trucks are usually rated to run at or near full throttle or torque for long periods of time. Cars hardly ever need to run full throttle for more than a few seconds to get up above the speed limit. Monitoring engine temperature and transmission temperature will help you stay out of trouble. Synthetic fluids will also help reduce wear under extreme conditions.

Perry

[andreasduess]

Originally Posted by mstephens

I have an Android Galaxy Tab 7" with OS 2.3, so it looks like that would work. $5 bucks is just latte money, so that's a no brainer. Thanks. Looks like it would be a great addition to our "tow instruments." We always have the Galaxy with us for towing if for nothing else, "Gas Buddy." It also is way easier for finding anything than our GPS, which has a horrible search engine (You must type the EXACT ASCII string value to find something).

EDIT: Whoops! Requires a $100 adapter! I spoke too soon about latte money.

Nope. A $7 adapter from ebay will work just fine.

Here's the one I bought: Auto ELM327 V1 5 Interface Bluetooth OBD 2 OBD II CAR Diagnostic Auto Scanner US | eBay

[mstephens]

Originally Posted by andreasduess

Nope. A $7 adapter from ebay will work just fine.

Here's the one I bought: Auto ELM327 V1 5 Interface Bluetooth OBD 2 OBD II CAR Diagnostic Auto Scanner US | eBay

Thanks. I saw those cheapies. The makers of the software tell you that such clones don't work.

Torque web site: "If you buy one of the cheap china OBD2 ELM327 bluetooth adapters from ebay / amazon, then make sure you have a good returns policy with the seller "

I guess for $7 there isn't much to lose though?

Did you have to try more than one?

[gmw photos]

And while Perry makes a good point about synthetic fluid being more tolerant of heat, I always suggest doing homework before making changes from recommended fluids. ( And it could be factory fill is syn.) Whether some backyard mechanics would like to admit it or not, very often those engineer dudes down at the car factory are pretty smart.
Here is an example that is not at all related to the OP's car, but this points out some of the logic that might be applied. Using my Frontier as an example, with it's manual six speed transmission. Nissan specs to use GL4 non synthetic gear oil in this transmission. Some of the guys that think they know better have swapped that out for something like Royal Purple systhetic. Then they experience shifting problems ( gear grinding). The issue is that syn ( or even GL5 non-syn ) is "slicker" than old fashioned GL4, and that extra slipperiness ( tech term there ! ) is not allowing the syncros to perfrom their function correctly. So it's a example of going with what the factory reccos is a smarter move.
Hey I am an old hot rodder too. There have been times that I thought I knew better than guys a lot smarter than me. There were times I broke parts that proved I was not so smart ( NOS on a CB1000F Honda, anyone ? )

[xrvr]

Older Dodge, but he can destroy anything. The OP should have no problem as long as he uses common sense when towing. No hard starts or violent downshift, and careful on normal braking. Jim

[kscherzi]

Originally Posted by mstephens

EDIT: Whoops! Requires a $100 adapter! I spoke too soon about latte money.

This $13 Amazon adapter claims to work with the torque app.

Amazon.com: LYL® mini small ELM327 v1.5 Bluetooth Mini Small Interface OBD2 Scanner Adapter Torque Android: Automotive

[andreasduess]

Originally Posted by mstephens

Did you have to try more than one?

Nope. Bought one, plugged it in, worked like a charm. Your mileage may vary on this.

[mstephens]

Originally Posted by perryg114

I would do research on the head problems for this model and see if the engine can be made reliable. Many times it is a case of redesigning the head gasket. If the problem can be fixed, you might be able to tow with it. Using a scan gauge is a great idea. I was able to program mine to display slip ratio which tells you that the torque converter is not locked and you are generating a ton of heat. You can boil the fluid in a big truck transmission if you push too hard with that torque converter slipping. Usually, you lock the transmission in a lower gear or just back off. HP is never the problem but how long you can run at max HP. Trucks are usually rated to run at or near full throttle or torque for long periods of time. Cars hardly ever need to run full throttle for more than a few seconds to get up above the speed limit. Monitoring engine temperature and transmission temperature will help you stay out of trouble. Synthetic fluids will also help reduce wear under extreme conditions.

Perry

So far, I have not observed any changes in trans temp while towing.

I am not sure how to tell when the torque converter is locked or slipping. What is the simple way to tell?

[dznf0g]

Originally Posted by mstephens

So far, I have not observed any changes in trans temp while towing.

I am not sure how to tell when the torque converter is locked or slipping. What is the simple way to tell?

By the feel by your butt...or watch the tach.

[jcl]

Originally Posted by MrUKToad

For me this year I did have a day where I was driving into a strong headwind all day at 60mph and the gauges showed increases in horsepower and engine temperature, running 110hp and at around 200F (air temp outside was a little over 85F), and that was for hour after hour. That's much higher than running solo, of course, but still with the manufacturer's limits. How tough are the engine components? Can I expect them to be OK when running at higher loads but within limits? On that trip, apart from awful gas consumption, the car showed no ill-effects but will the additional strain will result in a shorter life for the engine and transmission? It's anyone's guess, I think.

My work background was in heavy duty mobile and industrial equipment, often used in mining. Diesel engines in most cases, some natural gas engines. We tracked and guaranteed service costs over multiple years, and how the equipment was used had a big impact on those service costs. We and the manufacturer we represented used gallons of fuel consumed as a proxy for engine load factors and duty cycles, and in fact had access to published manufacturer overhaul intervals based on those gallons burned. I see no reason why the same formula wouldn't work with a gasoline engine that has a heavier than normal duty cycle/load factor, within the range of having sufficient cooling, and so on. So if you are burning twice the fuel, you can consider that you will wear the engine out twice as quickly. However, you aren't always burning twice the fuel, it may be a small portion of the time you use the vehicle. Also, with modern vehicles we often aren't wearing the engines out (rings, pistons, etc) within the useful life of the vehicle, however long that may be.

With transmissions, we usually worked in hours of use. We did have correlations to the number of shifts, though, and used that factor to adjust component overhaul intervals. With automotive transmissions, it wouldn't just be number of shifts, but how much time the transmission spends with the torque converter locked. The things they are doing to get better fuel efficiency have significant benefits to transmission life and minimizing heat, which is good for all of us. And that ZF 8hp transmission is an amazing product IMO.

Jeff

[mstephens]

Originally Posted by dznf0g

By the feel by your butt...or watch the tach.

Hmmm?

I don't know what that means in any useful way. I watch the tach all the time.

Maybe I would ask it this way. When I am going upgrade and holding the car in 3rd gear for miles, is the TC locked? The whole time? What would make it change states?

[mstephens]

Just got back from the dealer. The block is ok, so they are only replacing the heads. Car will be done Tuesday afternoon.

[dznf0g]

Originally Posted by mstephens

Hmmm?

I don't know what that means in any useful way. I watch the tach all the time.

Maybe I would ask it this way. When I am going upgrade and holding the car in 3rd gear for miles, is the TC locked? The whole time? What would make it change states?

Depends entirely on load at the time...and it varies by make, I assume. I'll tell you how GM works though.

TC can lock in 3rd - 6th gear, but it is dependent upon load and corresponding throttle opening. TC engagement feels like a very light gear shift. You have to be sensitive to it.

On the tach you'll see about a 50 - 150 rpm rise upon disengagement (again dependent on load) and it may not be a totally smooth tach needle movement, as many TCs are not "on/off", but rather PWM. Application will show a like drop in RPM. With an 8 speed, it might be difficult to tell the difference between TC and a shift, due to the close ratios of the gears.....I've not driven one yet.

[andreasduess]

Originally Posted by mstephens

Hmmm?

I don't know what that means in any useful way. I watch the tach all the time.

Maybe I would ask it this way. When I am going upgrade and holding the car in 3rd gear for miles, is the TC locked? The whole time? What would make it change states?

As far as I understand transmissions, you want the TC to be locked. It's when there's slippage that problems can occur, correct?

[mstephens]

Originally Posted by andreasduess

As far as I understand transmissions, you want the TC to be locked. It's when there's slippage that problems can occur, correct?

That's my understanding. Locked generates less heat. But, it's not totally clear to me how to control it. I have been assuming that if I hold it in a low gear, like 3 or 4, it will stay locked if I am on the gas, and might unlock if I let off on the gas.

[perryg114]

With all the gears that thing has, it will probably just downshift and relock the TC. The scangage will tell you the slip. If it is less than 1 it is slipping. Slipping amplifies torgue and generates heat. Temp rise is usually a sign. All the gears are to save gas.

Perry

[ggoat!!!]

Although this isn't technically what is actually happening, it can be useful to think of a torque converter unlocking as driving a manual transmission car and holding your foot slightly on the clutch so that the RPM's go up but the clutch isn't totally disengaged. The clutch is at that time "slipping" and heat as well as wear-and-tear dramatically increase. Although the torque converter in an automatic works nothing like this, it is a good way to THINK of how a torque converter slipping will affect RPM's and heat/slippage. A fully "out" clutch would be seen as equivalent to a locked torque converter; a "half way down" clutch would be seen as equivalent to an unlocked torque converter; slipping, but still propelling the car at higher RPM's.

Apples and oranges, but you get the idea.

[GCinSC2]

Totally unrelated to mstephens overheating issue.

ggoat described torque converter locking and unlocking and compared it to a manual transmission clutch. I'm NOT challenging his analogy but PLEASE PLEASE PLEASE do not use the a manual transmission clutch pedal as an attempt to increase torque, HP, passing power or anything. The only time the clutch can be used in a partial slip mode is during the initial standing start to get the vehicle in motion and maneuvering as in backing into your site. For maximum clutch life, minimize the amount of time a clutch is being slipped. This time is easiest described as the time that your foot is coming up off of the floorboard but the clutch is not yet fully engaged (foot completely off of the pedal), RPM in (from engine) is GREATER then RPM out to transmission.

Clutches create tremendous heat if only partially engaged, easily over 1000 DEG F is easily possible and very damaging to the clutch.

I claim no special knowledge of the inner workings of an automatic transmission. I do claim knowledge of automotive and pickup truck clutches, it is has been my sole profession for over 30 years.

Wishing mstephens a successful repair.

Gary

[gmw photos]

Originally Posted by ggoat!!!

Although this isn't technically what is actually happening, it can be useful to think of a torque converter unlocking as driving a manual transmission car and holding your foot slightly on the clutch so that the RPM's go up but the clutch isn't totally disengaged. The clutch is at that time "slipping" and heat as well as wear-and-tear dramatically increase. Although the torque converter in an automatic works nothing like this, it is a good way to THINK of how a torque converter slipping will affect RPM's and heat/slippage. A fully "out" clutch would be seen as equivalent to a locked torque converter; a "half way down" clutch would be seen as equivalent to an unlocked torque converter; slipping, but still propelling the car at higher RPM's.

Apples and oranges, but you get the idea.

Well, I see what you are trying to say, but the real problem with this comparison is it does not address the fact that when a TC is "unlocked" it is acting effectively like a lower gear, as it actually multiplies torque.
Slipping a clutch in a manual does not in itself multiply torque, although the increase in rpm would potentially ( likely ) result in more torque.

I have not driven one of these eight speed wonders either, but I am willing to bet it is going to be darn near impossible to tell when the TC is locking and unlocking with this trans. And since this design does not have a "tow mode" I doubt you have any practical tools at your disposal as a driver to control the TC lock/unlock.

EDIT: my comment about tow/haul mode is in reference to pickup truck trans like our 5R110 Ford that have that feature. Engaging tow/haul enables the TCM to alter the way the torque converter locks and unlocks, with the purpose being, as mentioned, to help keep trans oil temps lower. Tow/haul does other things also to the shift program.

[mstephens]

In 3rd gear and 3200 RPM doing 55mph, it would not seem like TC would unlock to multiply torque. That is nearing the peak torque of the engine.

This is a very interesting subject to me. Maybe there is an tech at Chrysler corp that can spell it out. if the scangauge type device indicates lock, thats a super reason to have one.