GM Synchromesh or Pennzoil?

[Roots-type]

There's probably a hundred discussions or more debating the two and which is better or that they are the same across the internet but no clear cut answer.

For purposes of a 3650 in a mach 1, does anyone have first hand experience here with either of these? A search came up empty.

Thanks.

 

[UnleashedBeast]

Rumor has it they are bottled by the same company, just different labels....toss a coin and pick one. Both are group II petroleum (dino oil). Cheap.

Want a real synthetic fluid in your transmission to make it shift like butter, look no further than this.

Amsoil Synthetic ATF

Despite what you read on the internet, Tremec specs ATF for their T56, T3650, and T6060 transmissions. They have come around to say that Synchromesh is acceptable, but not their first choice.

If you insist on Synchromesh, there are far greater choices than Pennnzoil/GM.

Amsoil Synchromesh

 

[Roots-type]

I've been using Mobil 1 ATF with a bottle of Lucas trans fix mixed in for about 4 years now, but I think the mixture is too thick. After the trans heats up, it shifts pretty well. When its cold, I have to really baby it or it will grind/not go in.

I'm sure the Lucas isn't helping, so I'm going to dump it all out and start with something else. Just don't want to use something that will screw up the trans. Its already got 80k miles on it, but i've been gentle for the most part.

So synchromesh is dino stock oil? You would recommend Amsoil? Any other additives like a friction modifier?

I really appreciate the advice, UnleashedBeast. Thank you.

Svtp, thank you too. Y'all did a good thing opening up this sub-forum.

 

[snakerider]

I ran both oils in my t56. I like GM synchromesh better. The tranny shifts alot smoother with GM oil.

 

[slowr w/o blowr]

Neither. save your dollars. I'm running a t56 and it takes 4 quarts, I think your 3650 takes 3.6 quarts. Anyhow, I run 3 quarts of el-cheapo mercon-dextronIII and 1 quart of Lucas oil automatic transmission stop slip additive. Its cheap, and i can promise you it works. I use it, all my buddies use it. Your synchros will grab and you can speed shift it till you burn all the hair off your palms. Enjoy!

 

[UnleashedBeast]

Check out the post I made in another thread. It's relevant here as well.

Been digging up some VOA's (Virgin Oil Analysis) on Red Line MTL, GM Synchromesh, and Amsoil MTF (synchromesh).

They look darn close to me, very hard to tell the difference in additive content. The major difference will be in areas a VOA will not detect, base stock type.

Red Line MTL - TAN and Oxidation levels suggest Esters (group IV) base stocks

GM Synchromesh - it has one heck of a Magnesium and ZDDP ppm boost.

Amsoil MTF Synchromesh

I've been using Mobil 1 ATF with a bottle of Lucas trans fix mixed in for about 4 years now, but I think the mixture is too thick. After the trans heats up, it shifts pretty well. When its cold, I have to really baby it or it will grind/not go in.

I'm sure the Lucas isn't helping, so I'm going to dump it all out and start with something else. Just don't want to use something that will screw up the trans. Its already got 80k miles on it, but i've been gentle for the most part.

Refill with straight true synthetic Amsoil ATF (requires 1 gallon). Do not use Lucas again.

So synchromesh is dino stock oil? You would recommend Amsoil? Any other additives like a friction modifier?

Correct, synchromesh uses petroleum base stocks.

No additional additives required, Amsoil ATF is robust. You can't buy a better ATF, period.

I really appreciate the advice, UnleashedBeast. Thank you.

Svtp, thank you too. Y'all did a good thing opening up this sub-forum.

You are welcome, and ditto on props to the new forum. SVTP is my #1 choice of car forums on the internet. I miss many events elsewhere because I never want to leave. Have much love for SVTP.

 

[Jimmysidecarr]

Don't forget the Royal Purple Synchromax (part #01512, quart bottle). It works great in any Tremec that specs an ATF. I have been using it since 2005 in my T56 6 speed Cobra and since around October in my Getrag 285 6 speed 04 SVT Focus.

 

[Brutal Metal]

For the 3650 you wanna run a conventional ATF like Castrol,Valvoline etc..
And Unleashed is correct the GM Synchro is made by Pennzoil..