Moss Motors, Ltd

Replaced the non-syncro first gear transmission in my TR3A with a "rebuilt" all syncro one.  When cold all gears including third work great.  When operating temperature is reached, third gear is very hard to downshift into.  I have tried double clutching, engine to transmission speed matching and slooow shifts to no avail.  In all cases there is gear grinding and as the tranny warms more, second to third shifts start catching a gear.  Any suggestions?

Thanks,

Glenn

Glenn,

A couple of questions come to mind. Did you replace/lubricate the spigot bushing in the crankshaft? What lubricant are you using in the gearbox? Did you check to see that the clutch disc slid freely along the input shaft splines before putting the clutch together? Was this transmission professionaly rebuilt? There are some really critical end float dimensions in the mechanism, and the second gear bush is easily fractured by heavy handedness during assembly.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill,

In answer to your questions:  spigot bushing replaced and lubed, clutch movement and fitment "looked" good, gearbox oil NAPA Stalube 85/90w GL4.  I purchased the transmission off of eBay and the DPO said it had been rebuilt - professionally?

What confuses me is the transmission is good cold but has the 3rd gear problem when warmed up.  Please ask more questions or give guidance as the next move is to pull the transmission (and when I do I am going to find one with overdrive).

Take care,

Glenn

 

Glenn,

I guess anybody that charges you for a service can call themselves a professional.

What bothers me is that the other gears begin to have problems with increasing temperature in the component. Are you getting enough "throwout"? Where along its total travel does the clutch seem to release/engage? If this is normal, it likely is indeed removal time.

Consider the five speed conversion to the Celica/Supra box. We're doing one right now for a customer, and I can tell you the components and instructions are first rate stuff. It also gets you away from the rather delicate nature of the Triumph transmission and the complexity of the overdrive. When installed it uses your original gear lever which sticks out of the original location, so it is not distinguishable from stock.

Let me know what you're finding.

Bill

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Bill,

The clutch engagemnt point depends on whether the external return spring is used.  If in place from the slave cylinder push rod fork to the slave mounting bracket, the clutch engages in the lower third of the petal arc.  If not in place, the upper third of the petal arc.  As far as the other gears having a problem, it is only when attempting to use 3rd gear.

Are you referring to the HVDA conversion?  Will the existing tranny cover and carpet for the TR3A work?

Thanks again,

Glenn

Glenn,

Excuse me, I was looking at your avatar when I mentioned the HVDA kit. You may want to contact them about it though.

Try to get the engagement as high as you can in the arc of the pedal, though I'm beginning to doubt this is your problem.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Bill,

Contacted Herman van den Akker and his kit works on the TR3 as well.  In addition to his kit you have to supply a Toyota transmission  and a TR6 pressure plate.  I'm definately leaning in the conversions direction, but I have to pause because $2700 is a little more that a six pack of good beer costs.  Oh well, I guess the TR6 supercharger from Moss will have to wait. 

If the float measurements are too tight, it is possible that heat expansion will cause binding (syncro failure, hence gear grinding)?

Thanks for all the input, you are really a valuable resource.

Take care,

Glenn

Glenn,

The usual scenario is that there is too much end play, leading to excessive thrust forces on the "hat" bushing, causing the "brim" to break off, which leads to gear misalignment and the forks are still trying to hold the slider hubs in place, etc. etc...

Yeah, I know the conversion is not just petty cash. On the other hand, it'll outlast five stock transmissions. I'm not slighting Triumphs here. Just think about how many years have intervened between the two designs.

Bill

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

I had the same problem for years with my TR4 trans.I also had it "professionally" rebuilt (ironically by Herman,back when he did that kind of work).He  took it apart a couple of times,and threw a lot of parts at it ($$$),but the problem never got better. I wound up sending it back to a guy named John in CT,who has a British trans shop called Quantumechanics. (Quantumechanics.com).He told me I had the wrong Third Gear in it.I guess there are a couple of versions that fit,but don't work.Anyway,got it back last week and put 1,800 hard HOT miles on it over the weekend.( Back roads to the Woodland CA .British show/swap, in triple digit temps).No shifting problems at all. A friend of mine who went with me on the trip was also running a trans in his TR4 that was just re built by Quantum,and he also had no problems. I can't say enough good things about John. Give him a call as he is very helpful.Hopefully you can salvage the trans you already have.For what it's worth , I have found in my 35 years of TR 3&4 ownership that  most  problems  are the result  of  improper  maint  and repairs,and the original stuff is pretty reliable.Hope this helps,good luck.