TKO-500/600 synthetic fluid or not?

[cazsper]

I always ran synthetic in my T-56 (6-speed) and it was great. Now I have a TKO-600 in my '68. Reading the forums, some people say not to use synthetic and some people say it works great. Anyone here have any opinions?

 

[Kit Sullivan]

Synthetic fluid is superior in all respects, as long as it is specified for that application. The only reason not to use it is if it leaks. Synthetic will leak worse and cost more.

 

[cazsper]

That's what I was thinking..

 

[MeZapU]

Synchromesh is a semi synthetic and it has never given me any cause to try anything different. I have a 3550 in two of my cars and shift quality is not an issue.

 

[cazsper]

Well, I have always used Amsoil ATF and my T56 always shifted great.

 

[Mesozoic]

Synchromesh is a semi synthetic and it has never given me any cause to try anything different. I have a 3550 in two of my cars and shift quality is not an issue.

You say you have a 3550 in 2 vehicles... I have one as well, did either of yours suffer from a 1-2 grind during spirited shifts? Mine's always had this problem and the only way to avoid it has been to slow down the shift.

That being said, I've researched on various other forums and folks are running Redline MTL in place of GM Synchromesh with good results, as it's formulated to be a drop in replacement with superior formulation.

 

[cazsper]

I just read that you shouldn't run synthetic in the T56 either. I ran Amsoil for years in my T-56 and it worked flawlessly..

 

[EdM]

Would seem using what Tremec recommends?

http://www.tremec.com/menu.php?m=110#Q1

 

[MeZapU]

You say you have a 3550 in 2 vehicles... I have one as well, did either of yours suffer from a 1-2 grind during spirited shifts? Mine's always had this problem and the only way to avoid it has been to slow down the shift.

My 85 GT behind a 408w. Shift it at the track at 6250rpms with no issues. The other is in my F-100. It rarely sees +5000 rpms with the stock 352's bottom end.

The Tremec is not a T-5 and its shift quality will not compare no matter what you do. Internally the Tremec 3550/500/600/TKO's are little more than a Toploader 4-speed with a 5th gear. Everything inside the transmissions are bigger and more heavy duty. The gear mass and synchronizer blocker rings of the Tremecs and Toploaders are exactly the same. If I gave you a Tremec brass blocker ring and one from a Toploader and you held them side-by-side, you could not tell the difference and they could interchange between transmissions. That being said, there is no way you can expect them to have the same shift "quickness" as a smaller T-5. They just take a little longer to shift and It's something you need to accept. Forcing the shifts lead to premature clutching tooth wear and internal gear clash/grinding.

 

[barnett468]

Synchromesh is a semi synthetic and it has never given me any cause to try anything different. I have a 3550 in two of my cars and shift quality is not an issue.

You say you have a 3550 in 2 vehicles... I have one as well, did either of yours suffer from a 1-2 grind during spirited shifts? Mine's always had this problem and the only way to avoid it has been to slow down the shift.

That being said, I've researched on various other forums and folks are running Redline MTL in place of GM Synchromesh with good results, as it's formulated to be a drop in replacement with superior formulation.

The grinding is often because the blocker ring doesn,t slow the gear down engough . . they sell special lined blocker rings that totally eliminate the problem.

.

 

[Mesozoic]

Synchromesh is a semi synthetic and it has never given me any cause to try anything different. I have a 3550 in two of my cars and shift quality is not an issue.

You say you have a 3550 in 2 vehicles... I have one as well, did either of yours suffer from a 1-2 grind during spirited shifts? Mine's always had this problem and the only way to avoid it has been to slow down the shift.

That being said, I've researched on various other forums and folks are running Redline MTL in place of GM Synchromesh with good results, as it's formulated to be a drop in replacement with superior formulation.

The grinding is often because the blocker ring doesn,t slow the gear down engough . . they sell special lined blocker rings that totally eliminate the problem.

.

That's very interesting. My friend runs a transmission shop and inspected my 3550... he said that the blocker rings could be replaced to remedy the issue, but the cost was astronomical. I decided to have it put back together and run it as is, it's done the 1-2 grind if I shift it too fast from day 1 (I bought it brand new).

Do you know where you can purchase the special rings?

 

[MeZapU]

Hanlon motorsports sells the carbon fiber lined blocker rings. Weak website but great customer service. Buy their Tremec rebuild DVD for $25 and install them yourself. Tremecs are actually very easy to work on. You don't even need a press unless you want to replace the tail shaft bushing. Much easier than even a T-5 to rebuild.

 

[EdM]

And the verdict on tranny lube is?

 

[Mesozoic]

Everyone using a 3550/TKO for road race is using either GM/Pennzoil Synchromesh or Redline MTL. I'm using Redline MTL.