Tremec 3550 Whine

larrym1961

5 Year Member
Dec 18, 2010
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Idaho Falls Id
Recently I went from Dexron III ATF to Syncromesh Trans fluid in my 3550. It has since developed a whine that almost sounds like a supercharger or gear drive to it. It still sifts and works just fine. Do I have a cause for concern?
 
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SynchroMesh comes in 2 flavors - black and white - the black is for manual transmissions, it takes a little less than 3 quarts and is expensive.
 
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I'd be concerned.
While I can't be for sure what it is, damage from whining usually means real trans parts in a rebuild, not just a small parts rebuild.
It will add up quick.
 
Whining can be a few things. It's hard to internet diagnose though.

It can be the meshing of the gearing itself. The change in fluid might have resulted in a slight change of the friction between the gearing which contributed to the whining itself. Switching fluids might fix this issue.

Or it could be the bearings. If they starve for fluid, they overheat and damage the race they ride on, resulting in whine. This is common with T-5''s that run low on fluid. The roller bearings between the input and output shaft starve for fluid, gall up, and then you have a noisy trans that needs parts replacement to cure the issue.

My suggestion would be to switch back. Tremec does state that the 3550 can be run on syncromesh or ATF D3. If it was silent with D3 and the only thing that changed was the fluid, I'd double check that the fluid is filled all the way up first, and then possibly change back to the original D3. Short of that, not much you can do unless you want to open the trans up and inspect parts.

You can probably live with it for a long time though. Plenty of guys here think all T-5s whine because most fox t-5s that have some miles on them probably do whine a lot, when the truth is a new or freshly rebuilt T-5 is pretty damn silent.

EDIT: while I reference t-5 a lot here, I know we are talking about a 3550
 
Whining can be a few things. It's hard to internet diagnose though.

It can be the meshing of the gearing itself. The change in fluid might have resulted in a slight change of the friction between the gearing which contributed to the whining itself. Switching fluids might fix this issue.

Or it could be the bearings. If they starve for fluid, they overheat and damage the race they ride on, resulting in whine. This is common with T-5''s that run low on fluid. The roller bearings between the input and output shaft starve for fluid, gall up, and then you have a noisy trans that needs parts replacement to cure the issue.

My suggestion would be to switch back. Tremec does state that the 3550 can be run on syncromesh or ATF D3. If it was silent with D3 and the only thing that changed was the fluid, I'd double check that the fluid is filled all the way up first, and then possibly change back to the original D3. Short of that, not much you can do unless you want to open the trans up and inspect parts.

You can probably live with it for a long time though. Plenty of guys here think all T-5s whine because most fox t-5s that have some miles on them probably do whine a lot, when the truth is a new or freshly rebuilt T-5 is pretty damn silent.

EDIT: while I reference t-5 a lot here, I know we are talking about a 3550
I am willing to bet it's the bearing race as U mentioned. We did an aggressive Moates tune on it and that is when the noise started. That was when I did the switch from the ATF to the Syncromesh and there was not much old ATF that came out when I drained it. So the bearings must have overheated due to the low fluid resulting in the trans whine I am hearing. Adding the Syncromesh must have made the noise more pronounced over the ATF.
 
If this was a t5, I'd say the pocket bearings are the culprit as when in 4th gear the input and mainshaft are 1:1 and no longer spinning. Unsure if the 3550 uses a bearing here.

Reason they become noisy is low fluid or incorrect fluid
 
If this was a t5, I'd say the pocket bearings are the culprit as when in 4th gear the input and mainshaft are 1:1 and no longer spinning. Unsure if the 3550 uses a bearing here.
Reason they become noisy is low fluid or incorrect fluid
It uses a bunch of small rollers with no cage. You pack the pocket with grease and put them in 1 at a time. It's been a long time ago, so I don't remember the exact roller count, but the manual says 17. Be sure to count them when you reassemble the input shaft.
 
A whining Tremec? The only whine I would expect is from me wanting one instead of the T-5 I worry about breaking.:)
(I am really following this for info.)
 
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The noise is definitely coming from the transmission. Same noise with old and new throw out bearing. The transmission makes NO noise when the clutch is pushed in. If you have ever heard a transmission with straight cut gears or a circle track car transmission this is what this 3550 sounds like. It had always been quiet until then.