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Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB (https://www.ft86club.com/forums/index.php)
-   Engine, Exhaust, Transmission (https://www.ft86club.com/forums/forumdisplay.php?f=8)
-   -   Transmission issue opinions requested (https://www.ft86club.com/forums/showthread.php?t=140366)

mrntd 05-14-2020 10:16 PM
Transmission issue opinions requested
 
I read a number of posts about the benefits of changing the transmission gear oil. When I changed the oil I did have some metal on the drain plug as it said I would. I added three quarts of Lucas synthetic gear oil and thought I was all set.


The issue is now when the transmission is cold first tot second, second to first changes are very notchy. To the point of difficult shifting. Once it warms up it is much better. Additionally when I'm on the power and pulling hard it becomes difficult to shift. I have the Edelbrock SC so pulls are harder than stock would be.


Why would this have happened when changing the gear oil? Would changing back to the stock oil or another brand solve the problem?

Ultramaroon 05-14-2020 10:24 PM
By mentioning hard pulls with your bad-ass Edelbrock SC, all I read is "I have absolutely no idea how a transmission works."

Spawn_Of_Creation 05-14-2020 11:10 PM
I use Motul Gear 300 and no issues. It feels better in cold starts too than the stock oil.

radroach 05-14-2020 11:27 PM
My opinion is that transmission shifting issues are more from flex in the drivetrain mounts. Stiffen the transmission and differential mounts with whiteline parts.

anticubus 05-15-2020 12:13 AM
Quote:
Originally Posted by mrntd (Post 3331085)
The issue is now when the transmission is cold first tot second, second to first changes are very notchy. To the point of difficult shifting.
Cold oil is thicker and doesn't lubricate as well. Be patient but firm after you start up on a chilly day. Same reason you really shouldn't be doing WOT pulls or going much past 4000RPM before your oil is up to temp, the machine just isn't ready for hard driving.

Also, this is why all modern oils are multi-grade. The lower the number, the thinner on the viscosity scale it acts at a specific temperature. 0W-20 oil acts as a 0 weight at "low temperatures" (These are per-grade, but usually around -35C to -40C), which is going to be more viscous than its "operating temperature" grade (100C). Gear oil is usually 70W-90, so it's pretty thick, but a 70 weight at -35C is still going to be pretty thick compared to a standard 70 weight at 100C, it will just be slightly thinner than a 90 weight at -35C, just the same as the 90 weight side will be thicker than a standard 70 weight at 100C.

Ultramaroon 05-15-2020 02:29 AM
Quote:
Originally Posted by radroach (Post 3331114)
My opinion is that transmission shifting issues are more from flex in the drivetrain mounts. Stiffen the transmission and differential mounts with whiteline parts.
But the only way to shift is with the entire driveline completely unloaded. There is literally zero torque applied at that moment.

mrntd 05-15-2020 08:36 AM
Quote:
Originally Posted by radroach (Post 3331114)
My opinion is that transmission shifting issues are more from flex in the drivetrain mounts. Stiffen the transmission and differential mounts with whiteline parts.

For the hard pulls you are most likely correct. I didn't think about that. Thank you.

mrntd 05-15-2020 08:37 AM
Quote:
Originally Posted by Ultramaroon (Post 3331088)
By mentioning hard pulls with your bad-ass Edelbrock SC, all I read is "I have absolutely no idea how a transmission works."

Your user name says it all.

mrntd 05-15-2020 08:44 AM
Quote:
Originally Posted by anticubus (Post 3331124)
Cold oil is thicker and doesn't lubricate as well. Be patient but firm after you start up on a chilly day. Same reason you really shouldn't be doing WOT pulls or going much past 4000RPM before your oil is up to temp, the machine just isn't ready for hard driving.

Also, this is why all modern oils are multi-grade. The lower the number, the thinner on the viscosity scale it acts at a specific temperature. 0W-20 oil acts as a 0 weight at "low temperatures" (These are per-grade, but usually around -35C to -40C), which is going to be more viscous than its "operating temperature" grade (100C). Gear oil is usually 70W-90, so it's pretty thick, but a 70 weight at -35C is still going to be pretty thick compared to a standard 70 weight at 100C, it will just be slightly thinner than a 90 weight at -35C, just the same as the 90 weight side will be thicker than a standard 70 weight at 100C.

I don't drive it hard until it is warmed up. Sorry for the misunderstanding. I understand the viscosity and temperature relationship. My "cold transmission" comment isn't necessarily referring to the outside temperature but more to the temperature of the transmission itself. This is a comparison to how it felt with the oil I just drained out of it. Both of the oils were/are of the same viscosity rating. Thanks

NoHaveMSG 05-15-2020 11:18 AM
Quote:
Originally Posted by radroach (Post 3331114)
My opinion is that transmission shifting issues are more from flex in the drivetrain mounts. Stiffen the transmission and differential mounts with whiteline parts.
I have stiffer engine, trans, diff bushings, diff brace, and solid subframe mounts. The engine and trans mounts improved shifter feel, but did not change how the transmission behaves when cold, or if you need to adjust your clutch pedal engagement point.

If the OP got 3 quarts of oil in his trans, it wasn't level. It takes 2.3 quarts, link to manual in Ultra's sig :D

churchx 05-15-2020 11:59 AM
I'm seconding NoHaveMSGs experience. Better oil (obviously filled to right amount, 3qt is overfill, which just like underfill may worsen shifting) & stiffer tranny bushings improved shift feel, but hard to get into 2nd when gearbox is cold is still there. I just accept that as given and don't see myself limited by that during first 5 minutes of driving for gearbox to warm up when one shouldn't push it anyway. Yes, it would be nicer if that behavior hadn't been there, but as otherwise gearbox works fine, and it's throws are rather short and feel precise relative to most cars i've driven before, so i'm ok with that.

NoHaveMSG 05-15-2020 01:20 PM
Quote:
Originally Posted by churchx (Post 3331254)
I'm seconding NoHaveMSGs experience. Better oil (obviously filled to right amount, 3qt is overfill, which just like underfill may worsen shifting) & stiffer tranny bushings improved shift feel, but hard to get into 2nd when gearbox is cold is still there. I just accept that as given and don't see myself limited by that during first 5 minutes of driving for gearbox to warm up when one shouldn't push it anyway. Yes, it would be nicer if that behavior hadn't been there, but as otherwise gearbox works fine, and it's throws are rather short and feel precise relative to most cars i've driven before, so i'm ok with that.
One more check mark in the "sane" column :clap:

Ultramaroon 05-15-2020 03:45 PM
Quote:
Originally Posted by mrntd (Post 3331202)
Your user name says it all.
My point is that if you truly want to learn about the transmission, humility is your greatest asset. Do you want to learn about your transmission, or are you here to have your preconceptions validated? If it's the latter, I'll kindly excuse myself. ;)

Spuds 05-15-2020 04:07 PM
Quote:
Originally Posted by anticubus (Post 3331124)
Cold oil is thicker and doesn't lubricate as well. Be patient but firm after you start up on a chilly day. Same reason you really shouldn't be doing WOT pulls or going much past 4000RPM before your oil is up to temp, the machine just isn't ready for hard driving.

Also, this is why all modern oils are multi-grade. The lower the number, the thinner on the viscosity scale it acts at a specific temperature. 0W-20 oil acts as a 0 weight at "low temperatures" (These are per-grade, but usually around -35C to -40C), which is going to be more viscous than its "operating temperature" grade (100C). Gear oil is usually 70W-90, so it's pretty thick, but a 70 weight at -35C is still going to be pretty thick compared to a standard 70 weight at 100C, it will just be slightly thinner than a 90 weight at -35C, just the same as the 90 weight side will be thicker than a standard 70 weight at 100C.
One note that isn't obvious there is that multiweight oil is still thicker at lower temperatures than higher temperatures. The number in front of the W represents the the theoretical viscosity of a single weight oil of the same thickness at the lower temperature if it were to be tested at the standard temperature.


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