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TR2/3/3A TR3 trans issue.

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doc50

doc50

Jedi Trainee
Offline
Got the beast up and on the road, and notice that the (newly 'professionally' rebuilt prior to my acquisition) trans pops out of 2nd gear when slowing hard. I can pull back on the gearshift and it stays in. Does that sound like something I can look and maybe adjust at from the top without pulling the trans? (Hands folded in prayer here).

Also, I want to upload a pic of the car for my avatar (...Luddite says what??).
Any quick tips?

Thanx,
Thom
1959 TR3
TS34909L(O)
 
Hi Thom. What fluid are you using? On my TR6 I rebuilt my transmission and used a synthetic fluid (Redline) and experienced the same issue. I installed an OD unit soon after so never tried switching back to non-synthetic, but before using the synthetic I never had that popping out of gear problem. I have heard of others with this same issue. No doubt you will get other suggestions, but this might be worth considering. Cheers, Mike
 
Mike, I'm using Valvoline 20-50 Racing oil per Ken Gillanders and a bunch of people who concur. It seems to be specifically a 2nd gear issue when under deceleration.
Sounds like you still have that issue? Is it only in 2nd?
Thanx,
Thom
PS: I'll try to delete the other (duplicate) post, but I still would like to know if anyone knows of a gizmo that would go inline the speedo cable that will allow me to change ratio. My speed shows 80 when I'm doing about 65mph actual. I think it's an OD-added issue.
 
Hi Thom

Problem is that that transmission (non-OD) is on my bench now as I replaced it with an OD unit so never had chance to check with different fluid. My problem with the synthetic was when downshifting into 2nd only. Otherwise, it was perfect. Others should offer some advice as it is not the first time this problem has been discussed.

Cheers, Mike
 
Is it easy to shift out of 2nd gear, or kind of notchy? If it feels smooth, then there is some chance that the detent in the cover isn't working hard enough. The manual spells out measuring the force and shimming the spring if necessary, but I've noticed that a lot of "professionals" don't bother to read the manual. ("Professional" just means you get paid for doing it, not that you're good at it.) You'll have to remove the top cover to adjust the detent force (a digital fish scale works well for measuring); but it can be done without pulling the gearbox. Anything else (unless perhaps the top cover is just coming apart) will likely require pulling the gearbox out.

FWIW, I run Redline MT-90 and love it. The OD doesn't seem to care either way, but the gearbox works significantly better than with the 20W50 VR1 I used to use.
 
Thanx for the info, Mike. It shifts fine through all gears up and down, OD works as designed. Just the 2nd gear issue. I will take the top off the trans and try to get the detent pressure up. First, however, I may just switch to Redline to see if that doesn't create enough 'surface tension' to keep it in gear. Either way, it's not a deal killer as is...just something more to consider...sigh..
Right now I'm taking apart the rear drum to see what noise has caused us to shorten our day trip today....always something..sigh...
Thom
 
doc50 said:
... I still would like to know if anyone knows of a gizmo that would go inline the speedo cable that will allow me to change ratio. My speed shows 80 when I'm doing about 65mph actual. I think it's an OD-added issue.
Click to expand...

Adding an OD does not affect your speedometer -- so long as you have the correct speedo head for your differential then your error is just a matter of calibration.

There is a 4-digit number on the face of the speedometer that indicates how many times it expects the cable to turn in one mile. Some observation and math possibly required, or you can just mention the number and which rear-end you have.

If the unit is correct then a crude calibration (reposition the needle) can be done easily but the results may not be linear (i.e. it is a single point calibration that may leave the unit incorrect at higher and lower speeds). In that case a more elaborate adjustment (such as changing the magnetism of the bar) may be called for (and is above my pay grade).
 
I hope the detent turns out to be your problem. "popping" out of gear, however, is frequently a sign of a worn slider gear.
 
Geo Hahn said:
Adding an OD does not affect your speedometer -- so long as you have the correct speedo head for your differential then your error is just a matter of calibration.
Click to expand...
Unless of course your OD came from a different car, with a different drive ratio.
In that case a more elaborate adjustment (such as changing the magnetism of the bar) may be called for (and is above my pay grade).
Click to expand...
The speedo that was in TS13571L when it came to me read wildly high; so I tried my hand at adjusting the magnet. Took some creativity, but the results came out very well (until I pulled it back apart to deal with a different issue and didn't get the needle back in the right spot).

As usual, I got excited about the project and forgot to take many pictures. But here is a shot of my homebrew demagnetizer (which as you can see is just a coil of ordinary hookup wire, wrapped around a bolt and connected to my soldering gun).


I went a little too far with demagnetizing at first, so then I had to remagnetize. Again just hookup wire wrapped around a bolt, but a U-bolt this time (the bar just fits between the arms of the U), and some big capacitors to put a big jolt of DC through the coil. (The batteries in the photo didn't deliver enough, so I used a 50 volt supply to charge up the caps.)



And a shot of the lathe driving an old tach cable, to serve as a speed reference.

 
I'm usually impressed with your techniques... but this time I am amazed.

I think I must have been in a Home Ec class while guys like you were studying Physics.
 
doc50 said:
PS: I'll try to delete the other (duplicate) post, but I still would like to know if anyone knows of a gizmo that would go inline the speedo cable that will allow me to change ratio.
Click to expand...
It's called a "ratio adapter" and any speedometer shop should be able to make one up to suit your needs. Popular with the 4WD crowd, to keep the speedo accurate with those giant tires and so on. Last time I asked, I was quoted $100 for the box and gears; but subsequent ratio changes were only $40.
 
Thanx all...this site is giving me all kinds of trouble, always has, can't respond ususally, so I'll wax eloquent here while I can, till it again, boots me off. I'll check a speedo shop, as anything to to with the techniques I see described here are pretty much above my pay grade.
I used a ratio adapter in our old Revcon to great success...finally... and will try t do the same again.

Since it won't let me start a new thread, I must hijack this posting to mention something about the rear brakes that just happened today:
The fiber part of the rear brake shoes on one side just separated from the metal and were flopping around loose but intact inside the drum. I wonder if anyone has ever heard of that happening?

Also, the way the shoes mount in the drum is weird. I can't find any similar type of mounting in the 'Big Red Book' or anywhere else. They are only held in place by the two springs and the assembly only slides on two felt pads, there is no 'brake shoe retaining pin, or even a hole where it would go.....IS THAT REALLY IT???

Sorry to 'cross-post' but I have no other way to post here right now, until Basil can help me.

Thom
1959 Triumph TR3
TS34909L(O)
 
doc50 said:
The fiber part of the rear brake shoes on one side just separated from the metal and were flopping around loose but intact inside the drum. I wonder if anyone has ever heard of that happening?
Click to expand...
Yup, I've seen it. Seemed to be the result of overheating in one case; in the other it was from a friend trying to reuse shoes that had been contaminated with brake fluid. The solvent he was cleaning them with (perchloroethylene IIRC) apparently dissolved the glue that bonded the linings to the shoes.

Also, the way the shoes mount in the drum is weird. I can't find any similar type of mounting in the 'Big Red Book' or anywhere else. They are only held in place by the two springs and the assembly only slides on two felt pads, there is no 'brake shoe retaining pin, or even a hole where it would go.....IS THAT REALLY IT???
Click to expand...
Yup, that's it. Only used on a relatively small number of cars, but definitely factory equipment. Oh yeah, they should have slots in the pistons as well, which also help keep the shoes in place.

PS, good luck with the browser issues.
 
doc50 said:
I'll check a speedo shop, as anything to to with the techniques I see described here are pretty much above my pay grade.
I used a ratio adapter in our old Revcon to great success...finally... and will try t do the same again.
Click to expand...
You might want to double-check whether the problem is really drive ratio, or just a speedo head that is wildly out of calibration. In my case, using a ratio adapter would have resulted in the odometer and trip meter reading way low, since it was only the speedo mechanism that read high.

I was looking into the ratio adapter to compensate for my short tires; but decided to change the diff ratio instead. Real Soon Now ... :nopity:
 
Randall, do you mean that there is a way to calibrate the speedo head??
Thom

"If you Don't Have New Spots in Your Driveway, You're Out of OIL!"
me
 
Randall, I don't see my post of a few minutes ago, so I'll try it AGAIN!!

"...double-check whether the problem is really drive ratio, or just a speedo head that is wildly out of calibration..."

Does that mean I could adjust the speedo head? I wouldn't mind trying that. Is there just a small set screw?

Thom

"If you don't have new spots in the driveway, you're out of oil."
 
When I was doing my speedo research I came across a Russian YouTube video with the same magnetizing setup you used, Randall. In the YouTube vid it was a small explosion when they instantaneously discharged those huge capacitors! It blew small tools off their able. I was too scared to try something like that! Does yours have a similar result?
 
CJD said:
In the YouTube vid it was a small explosion when they instantaneously discharged those huge capacitors! It blew small tools off their able. I was too scared to try something like that! Does yours have a similar result?
Click to expand...
Nope, just some limited sparks. I wonder what exploded? Some types of capacitor might have trouble with being discharged so quickly, especially if the capacitance was very large. The ones I used would not like it on a constant high frequency basis; but I had no trouble at all with my setup (and that photo was taken afterwards).

Thom, my point is that there are 3 separate mechanisms inside the speedo head. The odometer and trip meter are driven by gears, so it is practically impossible for them to read high (although they could read low if the gears are stripped, etc). The speedometer reading depends on a balance between the strength of a magnet and a hair spring, so it can easily read high if the spring weakens, etc. Adding a ratio adapter is going to affect all 3 mechanisms equally; while calibrating the speedometer will only affect the speedometer. Either or both may be appropriate for your speedo; but I don't know which. I'm just saying you should find out, before investing money.

It's unfortunately not nearly as simple as turning a screw. If you don't want to follow the steps that Geo & I outlined above, then there are any number of speedo shops around that can do it for you. But they are usually only interested in returning the instrument to it's original calibration; changing those little gears and so on is a bigger task and most shops don't have the parts needed. If the problem is really the drive ratio in your OD, then the ratio adapter is the way to go (assuming you don't want to just fix the OD).
 
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