Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 11-01-2019, 09:43 AM   #1 (permalink)
Master EcoModder
 
Join Date: Jul 2017
Location: Memphis, Tn
Posts: 463
Thanks: 320
Thanked 107 Times in 81 Posts
Shifting with torque converter locked

Hello everyone, I am wondering if it is bad for my 2005 Honda Civic’s transmission to shift with the torque converter locked up. With my solenoid mods to raise line pressure, it shifts somewhat hard when locked up and I am wondering if this is bad on it. I like hard shifts, but I certainly don’t want to destroy my new (to me) transmission by shifting it with a locked torque converter. I don’t allow it to shift while the converter is locked up because I am unsure of the long term effects of doing do.

Also, I modified my pressure control solenoids so the trans runs at a higher line pressure so it shifts quicker and so the TCC instantly fully applies whenever I want it to. What I did is I unplugged the pressure control solenoids and plugged in extra solenoids so it doesn’t set a code and go into limp mode. I have been running it for about 6K miles this way and nothing bad has happened yet that I can tell, but I am wondering if shifting with high line pressure is bad for the trans in the long run.

The trans does not shift excessively hard (by my standards) from the solenoid modifications, so I would expect that this modification could actually extend the life of my trans because it shifts quicker, meaning the clutches engage faster and slip for a shorter amount of time, but I don’t know a lot about automatic transmissions, so I may be missing something.

Thank you very much in advance, I really appreciate your help.


Last edited by EcoCivic; 11-01-2019 at 09:44 AM.. Reason: Added vehicle info
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 11-01-2019, 09:59 AM   #2 (permalink)
Somewhat crazed
 
Piotrsko's Avatar
 
Join Date: Sep 2013
Location: 1826 miles WSW of Normal
Posts: 4,043
Thanks: 462
Thanked 1,103 Times in 973 Posts
Traditionally, in a powerglide used for racing, no TC, the bands tend to wear out faster, particularly the low one used to get the car moving.

Notice the caveats.
The secondary and any other bands of a multi-speed modern trans probably wont see that much additional wear because the ring set is dealing with a moving car. In a powerglide, the low band is gone before anything else so that's the rebuild point.

OTOH, the majors unlock the TC between shifts for a reason, albeit for comfort and smoother shifts.

Worse case get an analysis on the fluid looking for band residue.
__________________
casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.
  Reply With Quote
Old 11-01-2019, 10:07 AM   #3 (permalink)
Master EcoModder
 
Join Date: Jul 2017
Location: Memphis, Tn
Posts: 463
Thanks: 320
Thanked 107 Times in 81 Posts
Quote:
Originally Posted by Piotrsko View Post
Traditionally, in a powerglide used for racing, no TC, the bands tend to wear out faster, particularly the low one used to get the car moving.

Notice the caveats.
The secondary and any other bands of a multi-speed modern trans probably wont see that much additional wear because the ring set is dealing with a moving car. In a powerglide, the low band is gone before anything else so that's the rebuild point.

OTOH, the majors unlock the TC between shifts for a reason, albeit for comfort and smoother shifts.

Worse case get an analysis on the fluid looking for band residue.
Thanks. Honda transmissions don’t have bands though, if that matters. What about extra wear from always running at a high line pressure?

Last edited by EcoCivic; 11-01-2019 at 10:31 AM..
  Reply With Quote
Old 11-01-2019, 12:34 PM   #4 (permalink)
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,175

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 269
Thanked 3,522 Times in 2,796 Posts
I don't know about Honda but old GM vehicles with early th700 transmissions shifted between 3rd and 4th with the converter locked up.
Shifting with the converter locked up customer complaints because you could really feel it when it shifts and it would break transmission mounting bushings.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Old 11-01-2019, 12:35 PM   #5 (permalink)
Master EcoModder
 
Join Date: Jul 2017
Location: Memphis, Tn
Posts: 463
Thanks: 320
Thanked 107 Times in 81 Posts
Quote:
Originally Posted by oil pan 4 View Post
I don't know about Honda but old GM vehicles with early th700 transmissions shifted between 3rd and 4th with the converter locked up.
Shifting with the converter locked up customer complaints because you could really feel it when it shifts and it would break transmission mounting bushings.
This trans will shift from 3rd to 4th locked as well, but I think only partially locked. It can’t be felt like when it is manually locked with high line pressure.
  Reply With Quote
Old 11-01-2019, 12:42 PM   #6 (permalink)
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,175

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 269
Thanked 3,522 Times in 2,796 Posts
Yeah the early TH700 only had electronic on or off for lock up.
A PWM soft lockup came later for GM.
If you can't really feel it shift then there is some electronic or hydraulic trickery going on.

By all accounts I have been able to find soft grocery getter shifts ruin transmissions faster as it wears clutches faster than hard shifts.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Old 11-01-2019, 12:45 PM   #7 (permalink)
Master EcoModder
 
Join Date: Jul 2017
Location: Memphis, Tn
Posts: 463
Thanks: 320
Thanked 107 Times in 81 Posts
Quote:
Originally Posted by oil pan 4 View Post
Yeah the early TH700 only had electronic on or off for lock up.
A PWM soft lockup came later for GM.
If you can't really feel it shift then there is some electronic or hydraulic trickery going on.

By all accounts I have been able to find soft grocery getter shifts ruin transmissions faster as it wears clutches faster than hard shifts.
Thanks. So I am right that disabling the pressure control solenoids so it holds a high pressure is actually better on the transmission? My old trans died shortly after I started messing with it, but at 243K miles I think it was just its time to go.
  Reply With Quote
Old 11-01-2019, 01:23 PM   #8 (permalink)
EcoModding Lurker
 
Join Date: Oct 2013
Location: Amherst, Ohio
Posts: 28
Thanks: 0
Thanked 7 Times in 6 Posts
FWIW my '17 Fusion locks the converter after it shifts into 3rd, has a 6 speed trans
I'd like to know why the engineers chose to have it this way.
Not saying it's wrong, just curious.
  Reply With Quote
Old 11-01-2019, 01:46 PM   #9 (permalink)
Master EcoModder
 
Join Date: Jul 2017
Location: Memphis, Tn
Posts: 463
Thanks: 320
Thanked 107 Times in 81 Posts
Quote:
Originally Posted by Keito View Post
FWIW my '17 Fusion locks the converter after it shifts into 3rd, has a 6 speed trans
I'd like to know why the engineers chose to have it this way.
Not saying it's wrong, just curious.
Interesting. My guess would be because they found that 3rd gear is the earliest they can lock the converter while still shifting smoothly. I noticed that at least with my car, shifting it with the torque converter locked up feels a lot harsher in lower gears. A 1-2 shift locked up jerks the whole car and makes the engine surge and doesn’t feel happy. But a 2-3 or 3-4 shift locked doesn’t feel nearly as harsh for some reason. My guess would be because the car has more inertia at higher speeds, but I don’t know for sure.

This could also be because some people don’t like the immediate and direct response of getting on and off the throttle that occurs with a locked converter. I notice this more in lower gears. I like the direct response, but some people may feel like it’s harsh.

Last edited by EcoCivic; 11-01-2019 at 01:59 PM.. Reason: Added info
  Reply With Quote
Old 11-02-2019, 12:12 AM   #10 (permalink)
Master EcoModder
 
gumby79's Avatar
 
Join Date: Dec 2014
Location: Butte, Montana
Posts: 725

little jona - '91 Dodge D 250 first gen cummins LE
Team Streamliner
90 day: 23.4 mpg (US)

Little Jona airo modded - '91 Dodge RAM 3/4 TON D 250 2×4 AUTO
Pickups
Team Cummins
90 day: 18.5 mpg (US)

The Salted Hound Jenny. - '87 Dodge Ram 50/D-50 5sp 4X4
90 day: 20.24 mpg (US)

Jona Allison aero - '91 Dodge Ram D-250 Le
90 day: 20.76 mpg (US)
Thanks: 208
Thanked 427 Times in 278 Posts
I had 2 options with my Allison 6sp install.
1 GM style, soft and squishy 1-5(1stOD) 5-6 locked shift
2 Allison style, 1-2,lock 3-6 locked shifts
GM went this way for a soft fill not longevity or controlling excessive heat.
Allison, went for longevity @ up to 26k lbs.
Ether way the TCM adjusts the apply and release solenoids timing(when) and rate (how much time it takes each) to make smooth shifts independent of controlling line pressure. Uncontrollable line pressure WILL destroy the trans with extremely violent shifts as timing and rate alone are inadequate.

Read up on how your particular trans controlls shift firmness. A shift kit may be the better option.

__________________
1st gen cummins 91.5 dodge d250 ,HX35W/12/6 QSV
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 31.32mpg 100mi 3.193 USG 5/2/20


Former
'83 GMC S-15 Jimmy 2door 2wd O/D auto 3.73R&P
'79 Chevy K20 4X4 350ci 400hp msd custom th400 /np205. 7.5-new 14mpg modded befor modding was a thing
87' Hyundai Excel
83 ranger w/87 2.9 L FI2wd auto 18mpg on the floor
04 Mitsubishi Gallant 2.4L auto 26mpg
06 Subaru Forrester XT(WRX PACKAGE) MT AWD Turbocharged 18 plying dirty best of 26mpg@70mph
95Chevy Blazer 4x4 auto 14-18mpg
04 Chevy Blazer 4x4 auto 16-22mpg


  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com