Amsoil 75w90 good for late model Gen2 transmissions?

[efnfast]

Is Amsoil 75w90 manual transmission/transaxle gear oil a good choice for a late-model (2001+) gen2 t56 transmission (with the syntorque sticker on it).

It says GL-4 and Chrysler MS-9070; where I'm getting confused is there are some posts suggesting that Tremec at one point said to just run Dexron III ATF in any T56 as gear oil may or may not work with carbon fiber blockers (which I think applies to the late-model transmission ..... but this is GL4 manual transmission/transaxle gear oil, not GL5 severe gear oil for differentials, so maybe the Tremec posts were in reference to GL5 oil). The factory spec is the Mopar 75W85 transmission & gear oil, which I'm pretty sure the Amsoil is basically the same as.

There are numerous positive posts about the Amsoil feeling like an improvement over the Mopar fluid, but most comments seem to come from pre-2000 and I think something changed in the transmission post-2000, so it gets a bit confusing....

 

[Steve-Indy]

A GL-4 is OK...just don't use a GL-5 in the T-56 tyranny.

Here are a couple of scattered historical FACTS:

Our 1995 Viper came with Dexron II e label

Our 1997 Viper came with Dexton III label

Our 1999, 2001, 2003 Vipers came with Castrol Syntorque labels

2008-2010 and 2013-2017 Vipers came with T6060 transmissions and use ATF+4

 

[efnfast]

I think I spent 5 or 6 hours reading every thread about T56s and transmission fluid at this point, lol

I started getting frustrated when people talked about mixing ATF and two different types of gear oils so I just threw in the Amsoil GL4 75w90 transmission fluid and took it for a drive - felt really good, way better than the 25yr old fluid.

btw, I discovered I <3 the Amsoil squeezie bag. Usually when doing transmissions and differentials i get out the fluid pump and pump it out of the bottle ... and usually have the hose pop out and spill it everywhere and usually make a mess .... their "new" squeezie bag is a huge step up from the pumping method

 

[maverickagm]

I feel like I read every post today trying to decide on fluid for my 1993 t56. The service manual calls for dexron IIe. My understanding is that a non-synthetic dexron III is required because of the paper-lined blocker rings in early t56 units. So in the case of a T56, dexron VI isn't backwards compatible since it's always synthetic.

I ordered Red Line D4 ATF. Their site specifically calls out use on. a T56:
"Also used with manual transmissions and transaxles like T-5, T-45, T-56 and late-model BMW, provides a GL-4 level of gear protection". It hasn't arrived yet, but I'll post back if it causes me any problems.

 

[Monopoly]

Is Amsoil 75w90 manual transmission/transaxle gear oil a good choice for a late-model (2001+) gen2 t56 transmission (with the syntorque sticker on it).

It says GL-4 and Chrysler MS-9070; where I'm getting confused is there are some posts suggesting that Tremec at one point said to just run Dexron III ATF in any T56 as gear oil may or may not work with carbon fiber blockers (which I think applies to the late-model transmission ..... but this is GL4 manual transmission/transaxle gear oil, not GL5 severe gear oil for differentials, so maybe the Tremec posts were in reference to GL5 oil). The factory spec is the Mopar 75W85 transmission & gear oil, which I'm pretty sure the Amsoil is basically the same as.

There are numerous positive posts about the Amsoil feeling like an improvement over the Mopar fluid, but most comments seem to come from pre-2000 and I think something changed in the transmission post-2000, so it gets a bit confusing....

How'd you make out? I'm 3000miles in 2.5 years on that amsoil 75w90 and no issues yet. 2001.

 

[efnfast]

I've only had a few drives with it but it feels really good so far.

 

[MoparMap]

I might have to go this route the next time around on my 04. So far I've managed to find Syntorq here and there when I needed to do fluid changes, but that's getting harder and harder since it has stopped production. I emailed Tremec directly and asked for their recommendation since the Syntorq was out of production and they said just a good quality synthetic ATF like Mobil 1. Basically every T56 on the planet used ATF from the factory except for the Vipers I believe, and I think the only real noticeable difference between the two is the neutral gear rattle, which I can hear in my T56 swapped 67 Dart. ATF probably also shifts nicer in the cold, but I know most Viper drivers don't drive their cars as cold as I've driven mine in the past.

 

[GTS Dean]

I run AC-Delco GL-4 in mine at the moment and it was formulated for the Vette/Cad T-56 transaxles. I'm very pleased with the performance and I'm very hard on the synchros. About to make the leap into rebuilding my own T-56s.

 

[Goggles Pizano]

I feel like I read every post today trying to decide on fluid for my 1993 t56. The service manual calls for dexron IIe. My understanding is that a non-synthetic dexron III is required because of the paper-lined blocker rings in early t56 units. So in the case of a T56, dexron VI isn't backwards compatible since it's always synthetic.

I ordered Red Line D4 ATF. Their site specifically calls out use on. a T56:
"Also used with manual transmissions and transaxles like T-5, T-45, T-56 and late-model BMW, provides a GL-4 level of gear protection". It hasn't arrived yet, but I'll post back if it causes me any problems.

That Red is synthetic so you are contradictions yourself and it doesn't call out what years of T56.

Remember that Tremec bought borg warner in 1996 and switch to syntroq was for that ngr tsb.

 

[lane_viper]

I run AC-Delco GL-4 in mine at the moment and it was formulated for the Vette/Cad T-56 transaxles. I'm very pleased with the performance and I'm very hard on the synchros. About to make the leap into rebuilding my own T-56s.

I've rebuilt The Viper's T56 and my Corvette's T56. Let me know if you have any questions.

Got 60K on the Corvette's rebuild with no issues.

You will need a shop press for the new bearings. A pair of C-clip pliers is another must.