TR6 TR6 Tranny

[TMike]

I recently purchased my first TR6 and am having problems when downshifting into 2nd gear. Fear synchronizer is failing. Any suggestions?

 

[TR3driver]

First check to see if the clutch is dragging. Hold the clutch down, shift into 1st then back into neutral. Wait a second or two (with the clutch still down) and then try to shift into reverse. If it grinds, something is dragging that shouldn't be.

If that is OK, I would suggest changing to Redline MT-90 gear oil instead of whatever you are using. It's a band-aid, not a cure, but it improves synchronizer operation enough that it may put off a rebuild. T'aint cheap; until you compare to the cost of a rebuild.

 

[hondo402000]

the oil might be low and as suggested just go ahead and change it

Hondo

 

[Kleykamp]

I'm having the same issue with a TR3.Car was a "barn find". I rebuilt the hydraulic part of clutch and found friction plate was sticking. It does not grind downshifting to second it just won't go in. I keep driving around the neighborhood, with lots of starts and stops trying to "burn off" whatever is on the clutch. It seems to have improved somewhat, but not enough to really trust it yet. How long should it take to clear up if its going to? Kind of hijacked the thread, but maybe an answer will help both of us.

 

[sail]

TMike. Welcome. Everything Randall said. I wouldn't worry about it too much. Be aware of it driving. When its cold be careful of second. Don't downshift flying in 3rd; wait till everything is going the same speed. Double clutch if necessary. Could be good for a long time.
I would think a stuck clutch, which is common, once it is un stuck should be fine. Are you sure hydraulics are good and slave adjusted?

 

[TR3driver]

on the stuck clutch. If it doesn't get better almost instantly, then it probably won't get better without mechanical intervention. You could try a somewhat longer trip at highway speeds, perhaps the heat and vibration would help, but I doubt it.

But the TR6 usually doesn't have an adjustment at the clutch slave (it's supposed to be self-adjusting), so don't be surprised if you don't find one.

 

[TMike]

Randall, Richard & Hondo,

Thanks for the recommendations. I'll check for the dragging clutch and change the oil using Redline MT-90 this weekend. I have noticed that it will occasionally grind when shifting into reverse, so something may be sticking. The clutch pedal was hitting the stop and I was concerned that it was not fully disengaging the clutch. I welded an extension to the back of the clutch pedal to increase travel (also makes the clutch position more consistent with brake and throttle pedals).

 

[TR3driver]

If insufficient pedal travel is the problem (a common problem with later TR6 from what I've heard), then check the pivot points for excess wear, especially where the pedal joins the pushrod to the MC. The clevis pin can be easily replaced, but the holes frequently wear oversize as well.

On my Stag, I wound up reaming the holes out a bit, and using a slightly larger metric bolt (with a smooth shank of course) as an oversize pin. Someday I'll pull it apart and do it right, but the bolt was enough to make it work for now.

Other solutions include installing a "SS braided" line from the MC to slave; and some folks have gone as far as installing the larger bore MC from an early TR6. The larger bore will make the pedal force higher, but gives some extra motion to help compensate for wear at the various points.

The joint where the slave joins the lever on the side of the gearbox should be less important, because the spring inside the slave is supposed to take up any slack at that point (as well as compensating for any wear in the friction plate). But you might want to check that the spring is doing it's job, sometimes they break or get left out. (Many sources don't show the spring, but it is supposed to be there.)

It is also possible for the spring inside the MC to break and cause lost motion; but that is usually severe enough that I don't think it is your problem.

 

[glemon]

I have been reading this thread with interest, I too have been having the with 2nd gear in my TR250. It isn't a grind it is like hitting a wall, won't go into gear. I rebuilt the tranny myself, all new synchronizers, bearings and bushings,most of the time it shifts perfectly, but sometimes I have this issue, the other day I thought maybe it was occuring when the tranny/car had been running a while and got hot, but it did it from cold the other day. Topped up the gear oil, no difference, I have tried pumping the clutch, then shifting, doesn't help, it does seem to be happening less since I put a return spring on my clutch pedal but still occurs.

If it was mechanical in the gearbox don't think it would come and go like that, it it was hydraulic I would think pumping the clutch would make a difference.

I am stumped, I also tested clutch arm travel roughly .6" give or take which seemed in the ballpark.

 

[TexasKnucklehead]

I had a problem that I had trouble understanding as well (in my TR6). The clutch seemed to work well when cold, and I had no trouble getting into reverse to back out of the garage. But after some time, I found I couldn't even get into first at a light. I also had recently rebuilt the transmission, and was pretty sure the issue was clutch travel.

What I found was the clevis at the MC/pedal was worn. I made an adjustable push rod from TR3 parts (that were not worn out), and now have plenty of travel.

 

[John_Mc]

I agree that the above suggestions are the more likely solutions. One additional area to check for wear and play in the system is the clutch pedal shaft bushing ( #47 in this diagram ) This is one thing that helped me the most when I first had clutch problems as that bushing was missing altogether. That said, I'm currently having the same issues as mentioned above and the bushing is not currently the problem.