6 speed vs. 8 speed trans

[jsl6v8]

my ram toolbox app says to change fluid and filter at 60k or 6 years if "using your vehicle for police, taxi, fleet, or frequent trailer towing."

and at 120k or 12 years it says to change the fluid and filter

 

[Lhemi]

Is anyone running a full synthetic?

 

[The Unabomber]

Is anyone running a full synthetic?

Factory fill is full synthetic.

 

[The Unabomber]

Some info on the 8 speed. Worth the read.

http://courses.chrysleracademy.com/MT201211/shell_popups/pdf/Reference.pdf

 

[Kustomblack1]

If its a 6 speed with 3.92 rear gear watch out

The fact is the 8 speed is great, but the 6 speed 3.92 rear gear set up is a perfect match. My 6 speed 3.92 is smooth running and pulls anything the 8 speed can pull plus a little more. No problems on inclines at all and shifts like a puller should up hill in low rpm without frantic shifting. This video is proof it pulls more off the factory line, by 10lbs or so I know but my point is made. The 8 speed 3.21 can pull 2000lbs less than my 6 speed. https://youtu.be/cS-KaD2_8Pkhttps://youtu.be/cS-KaD2_8Pk

 

[hoe...]

I have a zf 6 speed in my 2010 aussie ford pickup.
I change the filter and oil every 60,000km. I use fully synthetic oil that meets zf specs.
The pickup has 840,000km on it. Thats 520000 miles.
The gearbox has not been touched apart from servicing.
Funnily enough ford Australia quote the gearbox as 'filled with lifetime oil' and not to change it.
Zf themselves quote 120,000km service intervals.
I can assure the oil does get dirty by the time it is changed.
If I had the choice I would pick a zf gearbox every time, apart from very heavy duty work where I would go Aisin or allison every time.
I also have a hino Truck with 230000km on an Aisin 6 speed and a Nissan Truck with 380000km on an allison 5 speed. Neither have had any problems.

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[smurfs_of_war]

The pickup has 840,000km on it. Thats 520000 miles.

Holy crap

 

[hoe...]

Is anyone running a full synthetic?

Do not use anything but full synthetic oil that meets zf specs or you will destroy your gearbox.
They are very picky with oil type and level must be spot on.
Some oils that meet zf specs cause rough changes etc. It's a matter of trial and error to find the right one.
The genuine zf oil is very expensive, about $20 us a litre here.

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[Joji91]

Never driven a 6 speed but my 8 speed is awesome. Smooth shifting. But it does shift alot lol like every 5-10 miles if driven normal.

 

[Kotta390]

The fact is the 8 speed is great, but the 6 speed 3.92 rear gear set up is a perfect match. My 6 speed 3.92 is smooth running and pulls anything the 8 speed can pull plus a little more. No problems on inclines at all and shifts like a puller should up hill in low rpm without frantic shifting. This video is proof it pulls more off the factory line, by 10lbs or so I know but my point is made. The 8 speed 3.21 can pull 2000lbs less than my 6 speed. https://youtu.be/cS-KaD2_8Pkhttps://youtu.be/cS-KaD2_8Pk

Unfortunately while this is true to an extent, when towing most people do not tow lower than a 1:1 gear ratio on flat pavement. Especially when towing heavy. Any 1:1 or higher gear ratio will ultimately determine how much it can pull via the final gear ratio. In this case your comparison of a 3.21 and a 3.92.

Now that chart shows the equally equipped truck with a 6spd will pull 10lbs more... I don't understand why this is considering the 8spd trans is very well known on how efficient it is over the 5/6spd trans. It is possible they could run hotter with more load, IDK.. The 8 spd is better on fuel economy and has MUCH less drivetrain loss, which equates to MORE power to the rear/all wheels at any given time. There is a multitude of dyno sessions showing a stock 8spd putting down around 15-20whp more than the 6 spd equivalent. I have driven both with a 1800lb 20 ft. dove tail trailer and both had the same race truck on the back and coming from a dead stop and merging on the freeway, No frantic shifting or anything relating to what people would refer to as "hunting for a gear." The performance/economy of the 8 speed is vastly better.

On the other hand, the WOT downshifts on the 5/6spds are detrimental over time, which is another reason why I wouldn't want another one. Although my old 2006 Hemi got the dog crap beat out of it with a Hemifever tune and I never had one problem. I did COUNTLESS WOT downshifts. I may have been a lucky duck for all I know lol. Oh and don't get me started on the 6spd transmission, when it is really a super glorified 45rfe.

 

[RLJ10X]

Yeah, the 8 is probably the better tranny. But it wasn't available in 11.

The 545 in my truck is just fine, I think. I've gotten 20.5 mpg more than once. With 4.10 gears, it's fun to drive.

The grass is always greener.

 

[Tomater03]

8 speed is a all around better option. From towing to the drag strip. It's not even close. The 8 speed has shown with mild bolt ons and tune with prep to be able to cut 12.3-12.4 1/4 miles with no headers it motor work done on the factory 3.55-3.92 gears. That's a high mid to high 13 second combo for a equally equip 6 speed. Makes it hard for me to want to mod back up my 03 QC that most of you have seen on face book and YouTube. It was fast. But nothing compared to a equally modded 8speed. Excited to see how far these trucks go in the coming years.

 

[Kotta390]

8 speed is a all around better option. From towing to the drag strip. It's not even close. The 8 speed has shown with mild bolt ons and tune with prep to be able to cut 12.3-12.4 1/4 miles with no headers it motor work done on the factory 3.55-3.92 gears. That's a high mid to high 13 second combo for a equally equip 6 speed. Makes it hard for me to want to mod back up my 03 QC that most of you have seen on face book and YouTube. It was fast. But nothing compared to a equally modded 8speed. Excited to see how far these trucks go in the coming years.

If Diablo or HPT will release some trans tuning, that would be great..

 

[Ed loves guns]

The ol switcherooooo

Just bought myself a certified 2014 (bought in jan of 15) express 1500 yesterday.... Found a truck I liked, looked at the specs on the dealers website with the sales guy, comes with the 5.7, 8-speed tranny, a bunch of options I wanted, certified with only 18,000 miles. Awesome. Drove it around (apparently not paying attention) and signed the papers. Took it home and started rummaging through the info that came with the truck and found the original window sticker. 6 SPEED TRANSMISSION!! WTF?? I know I bought an 8, thats what I wanted and thats what we looked at. Nope. Punched in the VIN on about 5 different websites. 6 speed with 3.92s. Im not happy about this. I do 90% highway daily 32 miles one way to work. Although I dont do much towing I do want to have the capability for the near furture.

Can someone please tell me that im an idiot and somehow won the luck of the draw? Please?

 

[smurfs_of_war]

Theres no mistaking the difference. 6 speed does not have the rotary shifter. 8 speed does. If you wanted and were quoted the 8 speed, take it back. The 8 speed is a completely different truck.

If you have a shift "lever" you got the 6.

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[Ed loves guns]

Theres no mistaking the difference. 6 speed does not have the rotary shifter. 8 speed does. If you wanted and were quoted the 8 speed, take it back. The 8 speed is a completely different truck.

If you have a shift "lever" you got the 6.

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Yea I definitely have the stick on the steering column. This is my first Ram and the decision to buy a new truck came extremely suddenly and needed to be completed now. I thought I did a fair amount of research the night before but I guess not.

Oh and thanks for the near immediate reply!!

 

[misuracaf10]

Isn't everything better about the 8 speed? Plus 6 speeds have failure issues with Wide open throttle downshifts ? 8 speeds are nearly bulletproof is what I've been reading on this forum


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[JustB_rad]

I have a 14 Outdoorsman with the 3.92's and 8-speed. I tow a 7,000 lb TT with no problems at all.

Some things I've read about the 8-speed that haven't been mentioned here.

It's a sealed system....and virtually maintenance free.
It's synthetic lube is rated for higher temperatures. The 8 speeds normal operating temperature is between 185 degrees and 225 degrees IIRC. A 6 speed is in the danger zone if it gets near 200.

It's also designed to heat up faster because that leads to better efficiency in the driveline.

 

[Ed loves guns]

Theres no mistaking the difference. 6 speed does not have the rotary shifter. 8 speed does. If you wanted and were quoted the 8 speed, take it back. The 8 speed is a completely different truck.

If you have a shift "lever" you got the 6.

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Alright granted the "features" section says 25C package, the description of the truck says 8 speed. Thanks to Smurfs pointing it out, this truck also has a shift lever on the column. This isnt the truck I bought but another active listing thats just down the road from where I got mine.

https://www.truecar.com/used-cars-for-sale/listing/3C6RR7KT9EG286728/2014-ram-1500/20187/

 

[69GWC]

I drove both, bought the 8sp with no 2nd thoughts.
The 8sp kills the 6sp even with the 6sp truck having lower gears.