TR2/3/3A TR3 Transmission noises

[Moseso]

The transmission in my car has decided to call my attention to itself. It sounds great in 2nd, third and top. First gear has developed a minor clunking sound and reverse does the same thing, only I'd call it major, not minor.

I suppose it has to come out, no matter what, but I thought I'd post the symptoms here -- in case this is one of those familiar syndromes that someone recognizes, and, if so, y'all will tell me where to look first...

 

[Andrew Mace]

Could it be one of the propeller shaft u-joints? or a mount? Either might only "make a sound" when first reversing or when first starting forward from rest.

 

[Twosheds]

I have experimented with this...

I really hope it's something else, but in my case it was a broken tooth on the first gear countershaft, #60 on Moss' internal gearbox exploded view.

Rotten luck...

 

[Moseso]

Thanks Andy, but the sound is definitely coming from forward of the U-joint. I pulled the rubber plug out of the tunnel, over the forward joint, and it was not the culprit.

Twosheds -- Unfortunately, that's what my ear and intuition suggest too. I don't know exactly when I get the chance to do this, but I think the next step is to pull off the top cover and look down into that area. And then, probably, pull the gearbox out and tear it down... :frown:

 

[TR3driver]

Alas, I think John's right. However, just to make absolutely certain, you might put the car up on jackstands and run it in gear while listening and feeling from underneath. I was greatly hoping that the clunk-clunk-clunk in my Stag was a bad halfshaft/U-joint, but this test instantly proved it was inside the differential.

If you've got a magnetic drain plug, you can probably find the broken tooth stuck to it.

 

[Moseso]

I forgot to mention the potential upside: I have another gearbox that may well yield a serviceable part. When last run, it didn't make noises in first or reverse, though it sometimes popped out of second. The downside to the upside: That means I have to tear down TWO gearboxes.

 

[martx-5]

That's all upside as far I can see. Moss wants $290 for that part.

 

[DougF]

If you swap shifter caps, you may eliminate the popping from 2nd gear problem. Much easier swap.

 

[Moseso]

If you swap shifter caps, you may eliminate the popping from 2nd gear problem. Much easier swap.

Completely true. However, the current gearbox has overdrive. The spare box does not. That means two tear-downs if I want to keep the OD -- which I do.

 

[Moseso]

Twosheds and TR3driver are seers! I found the broken tooth exactly where Randall said it would be, and saw that it was broken off exactly where John said it would be.

The gearbox is out of the car and I have begun disassembly of the spare gearbox. I'm hung up at the point where I need the big long bearing puller to get the rear bearing off the mainshaft. Didn't find the tool in town yesterday, but I think Harbor Freight has one that I can get today.

The good news: While I haven't been able to see the teeth on the spare first gear yet, the countershaft came out REAL clean and good looking. The inside of that first gear is in good shape!

 

[Twosheds]

Well, I would rather be wrong if that meant that the culprit was easier to fix, but it sounds like you have the situation well in hand!

 

[Moseso]

Everything works now, and I'm back on the road! The countershaft 1st gear that came out of my spare gearbox was a fine specimen and runs quietly. Since the whole thing was out of the car and apart anyway, I decided to tackle the long engagement/disengagement times that were bugging me about the overdrive. The fellow I bought the whole OD gearbox from sent me a new accumulator spring and swapped my actuator rod for one he modified with a larger oil hole -- all for free! The difference is dramatic. Both engagement and disengagement are much quicker and more positive.

I'm again!

That makes me