T5z Experts -- Is this normal?

[edwardb]

I think I know the answer to this question without asking, but going to put it out there anyway. The T5z I purchased for my Mk3 build -- used but supposedly "perfect" condition -- has always had a problem downshifting into 2nd at anything above 20-25 mph. Just grinds. Every other gear combination up and down works perfectly and easily with no issues, including normal 1st to 2nd shifts.

I only use the car for street driving, so this is actually easy to live with. Generally only happens with turning at an intersection, and the natural tendency is to grab 2nd gear when going around the turn. If I'm under 20-25 mph, it drops right in and away we go. Above that, and only grind. The car pulls fine from 3rd at that speed, so just have to pay attention and it's no big deal. But the perfectionist side of me suspects something isn't right in the tranny, so interested in feedback.

Specifics of my setup: About to turn 1500 miles. At time of build a new flywheel, King Cobra clutch, throw-out bearing, pivot. SN95 pedal box, stock quadrant, Ford Racing clutch cable, stock SBF bell housing, 3.55 solid rear axle, aftermarket shifter (don't remember the brand) adjusted per their instructions, Mobil 1 Synthetic ATF fluid. The clutch is correctly adjusted, with about 1/4 - 3/8 inch of free pedal movement when disengaged, and I'm careful to make sure the clutch is all the way against the floor when trying to shift. This isn't a new condition. Has done it from the beginning.

Realistically what speed should I be able to drop it into 2nd? Accelerating in 2nd, it's past 60 mph before the rev limiter starts hitting, so seems like I should be able to downshift at a speed faster than 20-25. Within reason, of course.

I'm guessing I probably have a worn or damaged 2nd gear syncro. Something I could realistically fix myself? Never had a transmission apart before.

[Gordon Levy]

It does sound like the syncro is warn or cracked. It needs to be replaced. You might be able to do it yourself but I would advise having a pro do it.

[turbonut48]

MG s are notorious for 2nd gear wearing out. I used to double clutch when I really needed to use 2nd.
Harder on the clutch tho.

The Nut

[ZoaFan08]

My issue started with 2nd and then it was reverse. I ended up having the entire transmission rebuilt but you may be able to just have the syncro replaced.

[nc1mike]

The first thing to try is drain out the Mobil 1 Synthetic ATF fluid and add the correct fluid Dexron II. Synthetic is too slippery for the synchros to work properly. Call Tremic they will tell you to not use synthetic. It may not be too late and a simple fluid change may solve the issue.

Michael S.

[BigLeo69]

2nd gear is the slam gear syncros tend to go first, it also can have premature wear from keeping your hand on it while driving, and this wears on the sync-bushing

good luck

[ZoaFan08]

Originally Posted by BigLeo69

2nd gear is the slam gear syncros tend to go first, it also can have premature wear from keeping your hand on it while driving, and this wears on the sync-bushing

good luck

Did not know this, thanks!

[ROADRACER83]

I agree that some synthetic ATF's are too slippery for the syncros in a T5. I'm a big believer in Red Line D4 manual transmission fluid, though. It has some special additives that make the syncros brake when they are supposed to but still help prevent wear on the gears. It might be worth a try before you tear that puppy down. It kept the T5 in my American Sedan road race car alive for a couple of seasons after I thought I would have to replace the syncros.

Red Line Synthetic Oil - Gear Oil for Manual Transmissions - D4 ATF

Then again, maybe your 2nd gear syncro is totally shot in which case you are SOL.

Ron

[edwardb]

Thanks for the input. So a couple of follow-up questions:

1. Assuming I have 2nd gear syncro wear/damage, only downshifts could be affected? I've never had any issues going from 1st to 2nd.

2. I'm also assuming 20-25 mph is too low for a successful (e.g. non-crunch, non-grind) downshift into 2nd? What might be a more normal speed? (I realize this could vary somewhat depending on rear axle ratio).

3. I did some internet searching, and indeed confirmed as nc1mike said that synthetic fluid is not recommended for the T5z model Tremecs. Too slippery as he said, and doesn't play nice with the carbon fiber parts. Draining the Mobil1 and replacing is an easy fix. I did find multiple hits for GM Syncromesh fluid really helping with syncros and shifting, including for T5's. Valvoline's version of that fluid in stock at my local Advance. Maybe give that a try?

Thanks again everyone.

[J Persons]

A couple of months after I bought my NIB T5Z, I got a recall notice about the syncros, I didn't do anything about it because mine was working fine- until I trashed it behind my 331. It got replaced with one of Levy's T5's.
This was a known problem around 2005 or 2006.

[SPeace-ATL]

It would be normal to notice synchro issues when downshifting before it gets bad enough to happen during an upshift.

Beginning in the summer of 2011 Tremec redesigned the synchro rings for first and second to be a carbon-fiber design. Replacing the rings with the current design should help greatly.

The T-5 isn't too sensitive to fluid type, but gear oil or motor oil will damage the linings on the synchros used in Mustang T-5's after the 1984 production year.

Dexron-II spec fluid is not available, but Dexron-III equivalent has been considered the replacement since around 1972.

Most consider GM Synchromesh fluid or the Pennzoil fluid by the same name to be the best fluid for almost any manual transmission. I haven't heard of a Valvoline equivalent to Synchromesh, but I will be on the lookout for it.

Some synthetic formulas have been known to cause the non carbon-fiber linings in a T-5 to detach from the blocker rings. I have seen this first hand!

I've not known any issues like that with the Mobil-1 synthetic product.

Ford's present Mercon-V ATF is an excellent choice for a T-5 and is what a Ford dealer would use. Yes, it is synthetic...

[edwardb]

Originally Posted by SPeace-ATL

It would be normal to notice synchro issues when downshifting before it gets bad enough to happen during an upshift.

Beginning in the summer of 2011 Tremec redesigned the synchro rings for first and second to be a carbon-fiber design. Replacing the rings with the current design should help greatly.

The T-5 isn't too sensitive to fluid type, but gear oil or motor oil will damage the linings on the synchros used in Mustang T-5's after the 1984 production year.

Dexron-II spec fluid is not available, but Dexron-III equivalent has been considered the replacement since around 1972.

Most consider GM Synchromesh fluid or the Pennzoil fluid by the same name to be the best fluid for almost any manual transmission. I haven't heard of a Valvoline equivalent to Synchromesh, but I will be on the lookout for it.

Some synthetic formulas have been known to cause the non carbon-fiber linings in a T-5 to detach from the blocker rings. I have seen this first hand!

I've not known any issues like that with the Mobil-1 synthetic product.

Ford's present Mercon-V ATF is an excellent choice for a T-5 and is what a Ford dealer would use. Yes, it is synthetic...

Thanks for the great info! Very helpful. Looked at your website, and clearly you have lots of real world experience with these. So again, thanks.

I had a bit of a brain cramp when I typed my message though. The GM Synchromesh equivalent is in fact Pennzoil as you stated, not Valvoline. I've got the data sheet laying right here in front of me, says Pennzoil at the top, and I typed Valvoline in the posting. Nice.

I'm going to take out the Mobil 1 and give the Pennzoil a try. I'll report back how it works in the next week or two.

[MHCobra]

Originally Posted by SPeace-ATL

It would be normal to notice synchro issues when downshifting before it gets bad enough to happen during an upshift.

Beginning in the summer of 2011 Tremec redesigned the synchro rings for first and second to be a carbon-fiber design. Replacing the rings with the current design should help greatly.

The T-5 isn't too sensitive to fluid type, but gear oil or motor oil will damage the linings on the synchros used in Mustang T-5's after the 1984 production year.

Dexron-II spec fluid is not available, but Dexron-III equivalent has been considered the replacement since around 1972.

Most consider GM Synchromesh fluid or the Pennzoil fluid by the same name to be the best fluid for almost any manual transmission. I haven't heard of a Valvoline equivalent to Synchromesh, but I will be on the lookout for it.

Some synthetic formulas have been known to cause the non carbon-fiber linings in a T-5 to detach from the blocker rings. I have seen this first hand!

I've not known any issues like that with the Mobil-1 synthetic product.

Ford's present Mercon-V ATF is an excellent choice for a T-5 and is what a Ford dealer would use. Yes, it is synthetic...

Stan,
If you were going to chose, would you use Pennzoil Synchromesh or Mercon-V ATF or perhaps something else?

Thanks!

[SPeace-ATL]

Originally Posted by MHCobra

Stan,
If you were going to chose, would you use Pennzoil Synchromesh or Mercon-V ATF or perhaps something else?

Thanks!

I would choose the Pennzoil Synchromesh, but either should be fine.

[MHCobra]

I'm glad I read this thread. I had Dextron VI synthetic in my T5 for a few thousand miles, thinking full synthetic would be better than Dextron III. I decided to change after reading here. Based on the recommendation of SPease-ATL I put in Pennsoil Sycromesh. After just a few miles of driving I think my shifts feel smoother. Thanks Stan!

[edwardb]

As of tonight, the Mobil 1 synthetic is out, and the Pennzoil Synchromesh is in mine. Not expecting miracles, but we'll see if it makes a difference. Now it just has to stop raining...

FWIW, the Mobil 1 was bright red, clear, and smelled normal. This was with just over 1400 miles.

[SPeace-ATL]

I'm getting interested to see the opinions about the differences in shifting by comparing the synchromesh to other fluids in a T-5!

In my opinion, there is no reason to run from Mobil-1 Synthetic.
The Synchromesh is a little thicker and I think we will find that it may shift a little smother.

Tremec's official statement would be a Dexron-III equivalent for a T-5.
Dex-II was the original T-5 fluid. and was a little thicker than Dexron-III.
Today's DEX/MERC that is commonly available would be a generic Dexron-III equivalent since Dexron-II and III have been discontinued.

I hadn't heard of anyone using Dexron-VI until this thread, but it should have similar properties or they would not have discontinued the previous fluids.

Ford would use their Mercon-V Synthetic which is an excellent synthetic fluid as well.

As I've said many times, the T-5 is not too picky about the fluid. Just don't use gear oil or motor oil on a T-5 that has lined synchros. I've seen this fluid dissolve the composite type linings. (Not the carbon-fiber type).

I've also seen 2 cases where Amsoil Synthetic ATF had been used on T-5's.
They were extremely clean inside! But... The synchro linings "let go" of the synchro rings. I think this is why Tremec steers us away from synthetics because some of them have cleansers in them that will clean the linings right off the rings!

Enough on my "opinions" of T-5 fluids!

[Butch B]

I have used Royal Purple ATF in my t-5s with very good results.
hth
Butch

[J Persons]

What is the recommended trans fluid for the Magnum 6 speed?

[edwardb]

Quick follow-up to this thread. Finally back from a week long business trip, and drove the Roadster back and forth to the Woodward Dream Cruise. (Great event today, BTW, with incredible weather. I'll try to get some pictures up.) First time to drive the car since I changed to the Penzoil Syncromesh. I think it definitely shifts a bit better and the downshift into second is somewhat improved. But it's still won't go in at much over 25 mph. Clearly that syncro isn't quite up to par. As long as it doesn't get any worse, and I continue to only use for street driving, it's completely OK for me. At some point in the future will probably have to take care of it though.

[ROADRACER83]

edward:

This is a great time to learn and practice the skill of heel and toe downshifting and upshifting using neutral. Here's a link that will help to get you started. this site has some great tips on other driving skills also. If you can heel and toe, (actually rocking your right foot), you can work around the bad syncro. It will also make all your sycros last longer.

Rev matching & gear changing technique

Ron

[Tennessee Tim]

Originally Posted by ROADRACER83

If you can heel and toe, (actually rocking your right foot), you can work around the bad syncro. It will also make all your sycros last longer.

Simple rev-matching won't do anything to work around bad synchros. The only thing that would is double-clutching. All rev-matching does in bring the engine speed up to match the lower gear. Since the clutch is disengaged, the output shaft and countershaft, and therefore the synchros, are unaffected by engine speed. When you downshift, even whil rev-matching, the synchros still need to spin the countershaft up to speed.

Double-clutching - blipping the throttle in neutral with the clutch engaged between shifts - will spin the countershaft up to speed and therefore relieve the synchros of some of the force needed to get the countershaft up to speed.

Some people say that rev-matching on downshifts is actually harder on the synchros. The reason being that people tend to shift faster when rev-matching, and the faster the shifting, the faster the synchros wear.

Tim

[SPeace-ATL]

The second gear syncro ring is usually the first to go in a T-5.

The new carbon-fiber designed rings (released summer of 2011) are believed to be more durable, and so far have lived up to the expectation.

Almost always, when second is scraping the T-5 will need a new second gear, a new 1-2 slider gear (AKA Synchro assembly) and the synchro ring kit.

Logic would say a new synchro ring would do it, but the scraping will have rounded off the engagement teeth on the gear itself as well as the slider gear, so all three will need to be "refreshed."

You can heel-toe it in the mean time, but these parts will eventually be needed to fix the problem!

[edwardb]

Not quite understanding the heel-toe/rev-matching idea, but test drove it a little while ago trying the double-clutching technique. Have heard the term before, but didn't understand exactly what it meant. Drops into second like a champ. Like I said in the original post, for my cruising around driving the 3-2 downshift isn't needed all that often, but nice to know I can drop it in reliably. Thanks everyone for the great information.

[J Persons]

I got pretty good at double clutching the Fuller 10 speed in my Freightliner. But after awhile most drivers will "float" the gear change, that is, change gears without using the clutch. This is done by equalizing the engine speed with the road speed in what ever gear you are going into.