Harsh 1-2 shift
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Q45denver
- Posts: 945
- Joined: Thu Jul 25, 2002 6:24 am
- Car: 1995 Infiniti Q45t
1990 Infiniti Q45
1998 Nissan Frontier
Harsh 1-2 shift
Any suggestions for smoothing out a harsh 1-2 shift on a 1990 and a 1995 Q45? Would a rebuilt torque convertor with a higher stall speed help or hurt?
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goody90q45
- Posts: 3679
- Joined: Wed Aug 17, 2005 2:07 pm
- Car: 1992 Infiniti Q45 (sold)
- Location: Orangevale, CA
Re: Harsh 1-2 shift (Q45denver)
I'm not an expert on transmissions by any means but I was having the same 1 > 2 hard shift (except at WOT for some reason) and some slipping from 2 > 3 and 3 > 4 (mostly at WOT) on my 94Q with 144,000 miles on the transmission.
I took it to my local repair shop and had the BG transmission flush and filter replacement done and changed over to synthetic fluid. I'm happy to report that all the slipping is gone and the 1 > 2 hard shift is much improved.
It might be worth it to try the flush route first rather than bear the expense of a torque converter or transmission replacement. Good luck.
I took it to my local repair shop and had the BG transmission flush and filter replacement done and changed over to synthetic fluid. I'm happy to report that all the slipping is gone and the 1 > 2 hard shift is much improved.
It might be worth it to try the flush route first rather than bear the expense of a torque converter or transmission replacement. Good luck.
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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
Re: Harsh 1-2 shift (goody94q45)
After the BG Flush and ATF replacement, sequentially try Lubeguard RED additive, in 1/2 bottle increments a week apart up to 2 full bottles BEFORE tearing into a transmission for any reason.
Re: Harsh 1-2 shift (Q45tech)
I would very much recommend checking transmission temperature sensor. At about 100Kt had hard shifting problems. The sensor was bad and after replacing with a fixed value resistor it ran smooth as could be. Note that the firmness of engagement is varied with temperature. Let me know if you need further details.
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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
Re: Harsh 1-2 shift (sdkhalsa)
The temperature [and turbine sensor] can fail from abuse treatment in not replacing the ATF frequently before it turns very acidic from additive breakdown due to overheats.
Not common in those cars with 30k routine ATF changes.
One periodically checks AT parameters with Consult.
The shift pressure is set by the viscosity of ATF and a surrogate for this is temperature of ATF...............IF ATF is still with specifications.............which it is not after some period of time.
A single overheat above 212F [say 250F] can start the acidic process.
Normal max ATF is ~~ 174F-200F.
Not common in those cars with 30k routine ATF changes.
One periodically checks AT parameters with Consult.
The shift pressure is set by the viscosity of ATF and a surrogate for this is temperature of ATF...............IF ATF is still with specifications.............which it is not after some period of time.
A single overheat above 212F [say 250F] can start the acidic process.
Normal max ATF is ~~ 174F-200F.