Pennzoil Synchromesh mix

[Drew99GT]

Well, I may have done a bad thing, but I couldn't be happier with the results. I found on another message board where people were mixing Pennzoil/GM synchromesh with regular 75w-90 gear oil with awesome results. I have to agree! Just did a mix of 1 quart Pennz Synchromesh and the rest Valvoline dino 75w-90. I can downshift to 2nd again!! This combo beats everything I've tried, including Specialty Formulations MTL-R and doesn't even compare to Redline MT-90 (which shifted like crud after a while). Don't worry, it's a Toyota Corolla, so if I blow out the transaxle from this mix, all will not be lost. The junkyard is a phone call away

I was gonna try a mix of MTL-R and Synchroglide, but running that combo would cost more than the car at this point!

 

[MN Driver]

My recent replacement of dino to Amsoil in my Prizm(same engine/trans combo) seems to have caused a slow shift(including both upshift and downshift) into 2nd and a difficult shift into 1st even at about 5 mph when it would go in at about 20 mph effortlessly(not that it is done often), which I never have experienced a problem with except when completely cold but usually is gone after driving a block or two. After driving about 20 mins or more it acts how the old fluid was like. The synthetics just don't do it with the synchros in this thing or it's a viscosity issue when cold(odd being it's a synthetic that it would be too thick compared to a dino), I'm getting ready to make a change, I'm not sure whether or not I'd like to just drain a quart of the 75w-90 and replace it with the synchro fluid so I can have a decent viscosity again, if it's a viscosity issue it seems this would be of plenty benefit, if it's a synchro additive issue it would also benefit. I just feel that since I can't downshift to second that if I need the extra acceleration to avoid a crash in an emergency that I am going to have a huge problem.

 

[MolaKule]

It sounds like the transmission is on its way out and it preferred a slightly thinner oil than is specified by Toyota.

MTL-P may work better since it is the next lower viscosity MT lube.

 

[Drew99GT]

I think it is Mola. It's got A NASTY clunk when I let off the gas, like a bearing is loose. All the motor mounts are perfect. 2nd and 3rd gear synchros feel like they're shot. If the car was worth a darn, I'd probably try the MTL-P but it's not worth it at this point. But adding the quart of Pennz Synchromesh sure did smooth it out to a driveable level. I'll just let it be until it dies. Being that this is a Corolla, that may never happen! Thanks again for your email respones Molakule.

 

[MN Driver]

I've never got any clunks with mine, I have got a strange whine if I release the clutch in neutral right after starting it and the pitch varies with the engine speed, but it isn't there when it's warm. I'm thinking that I might drain about 1/2 quart of the Amsoil and replace it with some of that synchromesh. Before switching lubricants I never had an issue but with the Amsoil I is more difficult to get in second gear and sometimes when it does it, I feel a little bit of a tap against my hand as it goes in gear that wasn't there before.

 

[Drew99GT]

Probably throwout bearing MN Driver. Mines whines a bit when cold to.

 

[Drew99GT]

Just an update. Have 300 miles on the brew. Feels like I have a new transmission! Continues to shift flawlessly. I can downshift all day long even on cold mornings. I might try all synchromesh next time and see how that is, but that's going from the recomended viscosity of 15 Cst to 9.

 

[Mr Nice]

MolaKule,

Is it normal for the fluid (5 speed trans) to shear badly within 50K miles of normal driving ?

 

[MolaKule]

In our testing an ATF will shear down about 2.0 cSt and for MT's about 1.5 to 3.0 cSt, depending on the transmission.

For mineral oil formulations, it will shear down way below spec and then thicken up due to oxidation, which results in an out-of-spec thick fluid near the end of the fluid's life.

Our formulating philosophy is to start with a HD PAO and ester combination, and then provide plenty of EP/AW/AO and dispercency/detergency adds over the lifetime of the fluid in case it does shear.

 

[jeepman]

I know this is an older post, but for any future Prizm owners reference, I also used the 75W90/Synchromesh combo with great results. I tried 75W90 GL4/GL5 by itself, Amsoil GL4 MTF, and 75W90 Synthetic M1, and nothing worked well. The car is a 97 Prizm with a 5 speed, and the 1 quart of Penzoil Synchromesh combined with 1.7 quarts of 75W90 dino Quaker State gear oil did the trick. The transmission is shifting like new again with 118k on it. All of the downshift problems I was having are gone, and it upshifts like a knife through butter now. Since GL-4 is so hard to find now, this seems to be a winning combination IMHO.

 

[muddawgs]

agreed jeep.. this is good info if others are having these issues also or availability issues. been down that road also with 2 toy 4/5spd trucks many years ago with the same results using dino and m1 and have heard the same for amsoil etc.. i used dealer dino $$ purchased after my mistakes and have later used mola's mtl-p. ive have really liked its cold shifting and its shifting fine so far. i have heard good reports about redline also from other toy truck users.

 

[SilverGGA]

Mola, quick question. How does the Synchromesh's EP strength compare to a GL4 or GL5 gear lube?

I have been arguing endlessly with people on a forum which a guy suggests to mix Synchromesh with dino 75w-90 GL-5 and Redline shockproof lightweight in a trans-axle (front diff + trans) that specs 75w-90 GL5 (with 85w ok in lower temp). A lot of ppl use it in their brand new trans even they have no shifting problems to start with. I know the mixture will be thinner than spec and will definitely provide less protection than a 75w-90 GL5 under severe conditions due to lower EP additive, but not sure how much. Thanks.

 

[Zesty]

Sorry to bring this back up, but I have a specific question along these lines, maybe someone can shed some light.

My car is a 1992 Nissan 240sx, and I am looking to change the diff and MT fluids. It has a stock VLSD. The car specs 80w-90 for my climate, and GL-4 for the transmission and GL-5 for the diff.

Seems pretty simple, but it's not! I have heard from reliable sources that people are havning good results with the Pennzoil Synchromesh in these cars MT's, even though it is not GL-4 rated, and not recommended for Nissans AFAIK. To make things even more confusing, I have also heard that a GL-5 can be used, so long as it also has the MT-1 designation.....anybody have any insight on this?

Basically, I have a gallon of Valvoline 80w-90 gear oil that I was planning on using in my diff, but now I am thinking about mixing this with the Pennzoil Synchromesh in my manual transmission. Anybody know if that would be safe and/or smart?