I have a 1999 I30 with 71K km. Recently purchased, so I don't know how this car is "supposed" to behave.
I am experiencing mildly abrupt/harsh downshifts from second to first gear when coming to complete stops (makes the car feel like it lurches forward a little). This usually occurs around 10km/h.
I've been told by two Infiniti techs and one independent general mechanic that these obvious downshifts are normal, and is due to the design of the transmission. Is this true for this particular model?
I've recently changed the ATF to Mobil 1 Synthetic ATF, which seemed to help a little, but the downshifts are still apparent.
Any insight into this phenomenon will be greatly appreciated! Thanks!
VQboy
Obvious/mildly harsh 2-1 downshift when stopping
-
Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Nissamatic ATF is not the same as Dexron III or Mobil 1 ATF you need to add 5 ounuces of Lubeguard Black additive to approximate the slip/lock chacteristics of brand new Nissamatic.
In 90-96 usually not necessary but later FWD AT are different as are the new 5 speed AT 2002-2003 a special different ATF from Nissamatic D.............then you need 10 ounces of Lubeguard Black to approximate with Mobil 1.....................so trial and error testing required start with 5 work your way to 10 in 2003 models.......or just buy correct from dealer.
In 90-96 usually not necessary but later FWD AT are different as are the new 5 speed AT 2002-2003 a special different ATF from Nissamatic D.............then you need 10 ounces of Lubeguard Black to approximate with Mobil 1.....................so trial and error testing required start with 5 work your way to 10 in 2003 models.......or just buy correct from dealer.
-
autotech43
- Posts: 130
- Joined: Sat Jan 04, 2003 2:14 pm
Yes, the slight shift shock as you are concerned about is definitely a normal condition. There were many complaints concerning your concern when the I-30 first came out. I have checked many of the I-30's using the consult 11, and most of them at around 4 to 12 mph will show the shift solenoids making the switch to make the downshift occur, although you may notice it more under a cold engine condition being the idle speed is slightly higher than when the vehicle is at operating temperature. You may also notice, when slowing down as in when turning in a parking lot, and then accelerating, you might get a shift shock, being the TCM (transmission control module) is taking in consideration a number of input signal that MAY or MAY NOT allow the transmission to shift into first gear. If the transmission stays in second gear, the shock will not be there, being it didnt detect to shift to the lower (first)gear.Years ago automatic transmissions had a govenor and modulator valve that you could play with to make shift patterns and firmness changes accomodate the customer.From what you have stated, everything appears to be a normal condition.