Wii60 wrote:
I loathe my EX's transmission. So jerky around 3. Feels like its going to to drop every time.
What ever it is that u loathe keep the Infiniti trasmission out of it and stay away from the customer focus clinics on sporty cars - you'll water down the products for the rest of us.
I talked to some guys in the know and if by jerky you mean RESPONSIVE then I'm ALL FOR IT.
Computer geeks use the term GIGO. In this case IF the driver is romping & stomping ON/OFF the gas pedal then of course its going to be jerky.
Other deeper discussion with some really nice gear-head guys revealed possibility of gear 3 being the "Sweet Spot" for our engine/transmission - hp/tq output.
Research yielded the fruits of knowledge which I share here... gear 3 a perfect "midway" ratio in our gearbox. That coupled with the weight of the car and available tq are responsible for the jerky/jumpy/jaunty whatever we want to call it behavior.
Assuming AWD:
Drivetrain All Wheel Drive
Trans Type 5
Trans Description Cont. Automatic w/OD
First Gear Ratio (:1) 3.84
Second Gear Ratio (:1) 2.35
Third Gear Ratio (:1) 1.53
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.84
1st gear is 3.84 and 5th is 0.84
the difference being 3.00 giving our ratio-spread
going half way and "splitting the baby" yields 1.50
3.84 - 1.50 = 2.34 (pretty close to 2nd gear)
Everyone see what is going on here?
1st gear instantly "shifts up" to half of the ratio-spread of the transmission in 2nd gear the other half of the ratio-spread is shared amongst 3 other gears.
3rd gear at 1.53 is approx half again (2.35 - 0.75 = 1.60) of the remaining ratio of 1.50.
The fact that it is a little lower than a perfect 1.60 shows that the Nissan/Infiniti engineers were trying to extend the range of 3rd gear to have a greater "acceleration spread" allowing the car to "hang on" to this gear longer.
Having not driven this car on a dyno and not knowing its precise engine torque characteristics we concluded with great assumption that 3rd gear is the "FUN" gear out of all of them - especially on the open road.
By the time we get into 4th gear (perfect 1:1 ratio) and 5th gear (0.84) our engine is most likely out of its power range and either spinning too fast or too slow to turn tq into speed as quickly as it did in the lower gears as wind resistance continues to build.
I prefer to call it "sporty & responsive". What do u guys think?
Pretty good amateur analysis?
Also I won't leave out the possible maintenance issues:
1) transmission / Engine mounts
2) Some mechanical fault with the transmission
3) Worn out transmission/differential fluid.
4) Previous abuse of the vehicle.
Now I have a headache...
Oh and I always thought of the Juke as a nice & different mini-suv. Thought about it as an on-the-side commuter car for myself last year. Decisions
