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6 Speed vs 8 Speed

10K views 60 replies 26 participants last post by  robmease 
#1 ·
I'm looking at buying a 2013 Ram and just wondering what the gains are if I order the 8 speed, I've read 20% better mpg and 3 sec faster 0-60mph, What are your thoughts, Sorry if this is a double post I searched and didn't come up with anything
 
#37 ·
545RFE and 65RFE are virtually identical, both have 6 forward gears
(2nd prime re-named to 3rd) 2nd prime is the kick down (passing gear)
and not part of the normal upshift sequence unless using manal mode or tow/haul.

5 speed

1st 3.00:1
2nd 1.67:1
2nd Prime 1.50:1
3rd 1.00:1
4th 0.75:1
5th 0.67:1

6 speed

1st 3.00:1
2nd 1.67:1
3rd 1.50:1
4th 1.00:1
5th 0.75:1
6th 0.67:1

8 speed

1st 4.71:1
2nd 3.14:1
3rd 2.10:1
4th 1.67:1
5th 1.29:1
6th 1.001:1
7th 0.84:1
8th 0.67:1
 
#40 ·
EGADS! It's worse than I thought!!!

The General Public was ~lead~ to believe via marketing they were buying a '6 speed' and that the 6 speed 65RFE was 'something different' than the 545RFE advertised as a 5 speed,,,

Hmm,,, Other than the sticker in the window, it sounds like there was/is no discernible difference at all between how/when the gears were engaged between the old ~5~ and 'new' ~6~ speed,,,

LOL! Here is our 'new' 6 speed that, in reality, skips over '3rd' during upshifts, and can also skip over 3rd on downshifts,,, Basically, it's the exact same thing we sold last year as a 5 speed!

Sorry RAM, but that's kinda fukked up!!!

Dayum, I might have to go out and count the shifts in my 8HP70 now!!! LMAO!
 
#41 ·
Been discussed quite a few times before, lots of threads on it here.

Wanna know something else? The same transmission was originally released as the 45RFE, a 4 speed. A software update changed it to the 545RFE.

Its a reliable transmission
 
#46 ·
I shift 1-2 at 6200-6400, about 6000 for 2-2nd prime

Raced it 4 years in a row like that, about 100 passes per season
didnt actually smoke my OD frictions until I supercharged it.

(click pic for video)








...and that was before I put the blower on last year
now it can Chirp second gear in 4WD too :SHOCKED:
 
#45 ·
Many seem to think the 545 and 65 are totally different transmissions
but its mainly a software upgrade from a 545RFE to a 65RFE
....and a slight valve body mod.

The 545RFE is actually an old 4 speed 45RFE with a second overdrive added
and was originally designed to go behind a 235hp 4.7L Grand Cherokee in 99'

...never meant to handle Hemi Power


...and all are turds (IMHO) LOL!



Burned up 4 of them within a year :smileup:


The new ZF 8Speed is the first significant transmission "upgrade"
in a Ram since the Hemi was added over 13 years ago
 
#47 ·
So the transmission is a turd because you boosted your output over the transmission's torque rating of 410 lb-ft?

Its perfectly capable of handling Hemi power.
 
#49 · (Edited)
So the transmission is a turd because you boosted your output over the transmission's torque rating of 410 lb-ft?

Its perfectly capable of handling Hemi power.

spend much time in the drag race/ 5.7Lperformance sections?

Dozens of Rams roasted their OD frictions with just a few bolt-ons
with just intake, exhaust and tune. Its the weakest link in the trans.
If you'd like I can find a LOT of posts with failures on several forums.

here's a few I found in no time at all...

http://www.ramforumz.com/showthread.php?t=182629

http://www.ramforumz.com/showthread.php?t=153656

http://www.ramforumz.com/showthread.php?t=171789

http://www.ramforumz.com/showthread.php?t=141021

http://www.ramforumz.com/showthread.php?t=146580



My latest build has the stock OD clutch pack (with 3 steels and 4 double sided frictions)
replaced with 14 single sided frictions from a 68RFE (Diesel trans)
Seems to be working much better now, along with an extra 50psi line pressure to hold them together
(shift kit, valve body and pump upgrades + custom tuning).
 
#48 ·
Yea, mine is stock except for the 93 tune and I drive it 100 miles a day. Sometimes I wonder why I installed the tune except that it has so much better throttle response, the MDS is turned off and the transmission shifts so much firmer. Premium at just over $2.00 makes it hard to switch back to stock also.
 
#51 ·
The 545RFE is actually an old 4 speed 45RFE with a second overdrive added
and was originally designed to go behind a 235hp 4.7L Grand Cherokee in 99'

...never meant to handle Hemi Power


...and all are turds (IMHO) LOL!
Stupid statement. All of you with 6 speeds, study my pic closely...I was towing 7000 pounds into a 40 knot head wind maintaining 65 MPH for 95 miles. Don't sit there and tell me the 6 speed sucks. The freaking engine was going to blow before the tranny was....compare their temps....enjoy your 6 speed. Its more than enough for our Hemi.....
 

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#53 ·
I get that it was outdated, but its a reliable transmission.

No truck manufacturer is going to design trucks for the "racing community"
 
#54 · (Edited)
...off the top of my head;

GMC Typhoon/Syclone
Ford Lightning
Ram SRT-10 ....gee wonder what the "SRT" stands for ? ( maybe Street and Racing Technology?)

yup, no ones ever raced in one of those

People will race anything, does not have to be factory built for it
half the fun is DIY :D

My first Ram from 10 years ago,
04' QC 4x4 Sport, completely bone stock, 345hp
had the entire trans (545RFE) replaced under warranty within 90 days



I was worried that they were still using the same POS trans when I bought my 2010 6 years later
with the new Eagle Hemi putting out 50HP more than the old Hemi.

Before the 04' Ram I had a 94 Jeep Grand Cherokee 5.2L,
same turd trans, but unloaded quickly at the first sign of trouble for a 5 speed Manual 97' TJ



followed by a 01' TJ (6" Lift, 37's Locked and Loaded with 4.56's and front and rear ARB Lockers)


I'll be the first to admit I like to push the boundries,
I've been doing it since I built up my first 4x4 in 1982



After 33+ years modding trucks/jeeps I feel pretty confident about my opinion when I call something a "turd"
and I know from real world experience what I classify as "reliable" or not. Member of several off-road groups
and a Jeep Jamboree Trail Leader for 10 years I've seen a LOT of carnage, done tons of trail fixes to get people home.
 
#56 ·
You know you're right, I poorly articulated myself. What I should have said was that they are not going to design their standard (i.e. non-special edition models) for it. I understand people want to race things, but saying your trans is unreliable because you tuned, or put a blower on your engine, etc... that caused its output to exceed the transmission's rated capacity is like saying that your Smith and Wesson Airweight J-frame rated for .38 special+P is a turd because it blew the cylinder when you shot .357 magnum rounds through it.

That's what built transmissions are for:smileup:. What did you expect to happen?

Houston Hemi, I drove dad's 2009 Ram whenever he wasn't paying attention to where the keys were. Driving the Honda let me save up my money for my truck
 
#57 · (Edited)
You know you're right, I poorly articulated myself. What I should have said was that they are not going to design their standard (i.e. non-special edition models) for it. I understand people want to race things, but saying your trans is unreliable because you tuned, or put a blower on your engine, etc... that caused its output to exceed the transmission's rated capacity is like saying that your Smith and Wesson Airweight J-frame rated for .38 special+P is a turd because it blew the cylinder when you shot .357 magnum rounds through it.

That's what built transmissions are for:smileup:. What did you expect to happen?
I killed several 45RFE/545RFE's long before I bought my 10' Sport, OR the Supercharger, so expected failure
...and I never installed the Blower in my Ram until I had a purpose "Built" transmission from L&M Customs ($3k), and a custom built ATS Triple Lok TC ($1k) waiting to go in. :gy:



I had my Ripp kit sitting patiently in my basement waiting since May 2013, ordered custom trans right away
L&M transmission arrived in July, blower installed the following weekend. Stock trans lasted almost 2 months,
while I was waiting for my custom trans tuning for the new one...new trans went in the day after the stock trans lost OD clutch pack.

Even a built trans is no guaranty,
I roasted OD frictions and rebuilt both transmissions twice already.

Gotta Pay to Play :smileup:
Just happy I saved a ton of $$$$ on DIY
OD frictions are cheap. about $40/set, fluid/filters run another $150

Got the swap down to 5 hours with a buddy on my driveway




We did my Bud's truck too (Twice)


Before he threw in the towel and traded it on a Camaro SS with a 6 speed manual trans lol

 
#58 · (Edited)
The 6 speed auto in the new 5.0 GT's is a pretty good example of a stock transmission that can hang after some pretty good power upgrades and abuse and it has nice usable ratios also. The draw backs to our 6 speed make the performance of our HEMI that much more impressive to me. Stock 5000+ lb pickups that can run in the 14's at over 90mph in the 1/4 mile takes some power. Anyone who drag raced their street car 30 years ago can relate to this. I used to bracket race my 72 F-150 LB that had a 69 428CJ with headers, C6 auto with a 3.25 open rear. The best I got in the South Texas summer heat was a 14.62 at 98mph and that truck weighed a lot less than my Express. I think my Express may be a little faster.
 
#59 ·
I have 0 interest in power adders or even an exhaust system on the current Ram. It gets respectable MPG and will tow anything I own better than well. If I want to go fast and beat on stuff I go grab the old cars or the SRT stuff although I do appreciate the usable and brisk power the 5.7 puts out in stock form (hence why I own the truck).

That said, Chrysler in general has a bad habit of taking older stuff that was great when first designed and adding to it and destroying the original great product. Basically any transmission that was base off of the 904/727 was less than stellar. The 3.7 and 3.9 liter V6s were complete turd city. Terrible power/Economy/Horrific engine harmonics and noise.

I am aware of Chryslers past transmission issues (mostly due to lack of proper maintenance) but I am hopeful this rig which I intend to keep a long while will go every bit of 200-230k without a transmission rebuild.

Can anyone weigh in on the use of a finned aluminum larger capacity transmission pan? likewise on the use of a finned aluminum rear diff cover? It tows very frequently but the largest load it probably will see a few times a year would be around 6500 lbs trailer weight.
 
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