View Full Version : Mopar rumor confirmed: 8 speed auto's

Prince Valiant
01-10-2011, 01:12 PM
During the press conference releasing details and images of the revamped chrysler 300, it was confirmed that 8 speed automatics would be available in the near future. It was always assumed that higher end SRT's and Ram HD's would get these units...but in the press conference, they talked about how they'd be available even with the v6, helping the 300 v6 acheive 30mpg hwy.


The 8 speeds are ZF 8HP derived units...licensed to be built at their plant in Indiana. These transmissions have been used on Audi's, Bentley's, and BMW's with good success in both high power and mid power levels.

The ratios are as follows:
1st- 4.70
2nd- 3.13 (more aggressive than a lot of older 3 and 4 speeds 1st gear)
3rd- 2.10
4th- 1.667
5th- 1.29
6th- 1.00
7th- 0.83
8th- 0.67

using the current 3.06 rear end, this means loafing along at 75mph at 1800rpm's. With 2.82's it's 75mph at only 1650rpm...yet all would have a far more aggressive take-off versus the current standard 3.59 1st gear of the 5 speed auto, and 2.2 of the second gear...

Shift times are around 200 milliseconds in aggressive upshift situations.

An example of how it positively affects performance of in even mild applications can be seen in the AWD bmw X3 (C&D)...with only 300hp and 300ft-lbs of torque, and in a vehicle that has a curb weight of over 4200lbs, it turns 14.2 @ 97mph...it's 1/4 mile time belies it's weight and modest power.

So consider then that cars like the V6 challenger (305hp) and Charger/300 (292hp) with less weight than even the bmw with these transmissions? Or the similar weights of more powerful R/T or 300C? Not too mention the 470hp SRT's that will get these units.

There is reportedly work on higher torque units for HD truck applications (the regular units are rated for around 700ft-lbs of torque).

The amazing thing about these transmissions is that they cost LESS to produce than typical 6 seeds, use less moving parts than most 6 speeds, and thus use less power to turn as well as being stronger...here's hoping they get here soon though. Can't happen quick enough imo.

01-10-2011, 02:20 PM
Good move on their part, plus the cleaned up look of the 300 should make it more of a competitor in the luxury car segment.

Bobby "Big Daddy" Flay
01-10-2011, 04:05 PM
It looks like every other Chrysler, a Sebring!

01-10-2011, 05:00 PM
Sounds good. I love a well set up automatic and will probably end up looking at
an SRT Jeep (assuming they do one on the new model) or an SRT Challenger.

Plum Crazy
01-10-2011, 06:20 PM
I just took an online test about those, and the new Dual Dry clutch Automatic

Prince Valiant
01-10-2011, 06:24 PM
Sounds good. I love a well set up automatic and will probably end up looking at
an SRT Jeep (assuming they do one on the new model) or an SRT Challenger.

SRT Jeep mules have already been spotted so it's certain there will be a SRT GC. SRT's have been seen testing the 8 speeds...

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One interesting thing about the trans is that despite the increased strength and gears, it's smaller and more compact than than most 6 speeds...and far more compact than the mopar 4 and 5 speeds.

SO, that begs the question...will this unit be available and an attractive retrofit option for older muscle cars? Since it'll be used behind the hemi, it'll use the same bolt patern that LA engines use...though an adapter plate would be needed for B/RB engines.

Has anyone used the 6 speeds from modern corvettes, etc to retrofit to muscle cars?