How sweet if was AND overdrive question

[GilsTR]

With all the nasty weather around the country...as one can easily see from the photo posts on Pauls posting...I have not dared to post anything about the great weather here in NoCalif. This past Saturday took the Redhead (60 TR3A) for a 5 hour ride down thru the Napa Valley. The hill sides are a beautiful green...and the vineyards are bursting with beautiful yellow Mustard. Took along the camera...and really had a fine time. That is...until the overdrive quit working.
The overdrive has never had a hint of problems...until when I went to shift into 4th over it did not have its usual snappy response...but in a minute did drop in. Same the next two shifts. Then...it won't go in at all. The ride home was a little slower driving in 4th no over. But 55 on those 2 lane roads was not all bad.
I will start checking the fluid lever...hope that is the easy fix.
Anyone out there in Forum land have any input on where to check next?
Gil NoCal

 

[Brosky]

How about the filters? I know that the "J" type has two round metal strainers above the screen that is under the cover on the bottom. If they gum up, shifting can become slow to none existent.

Of course this is assuming that you have oil. That, as you said is the number one item to check.

The "A" type in the TR3 may not have this configuration, but I'll bet it has something similar.

Randall knows a lot about these and I'm sure he'll be around soon to give some sage advice.

 

[TR4nut]

I have the A-overdrive for my 3A scattered in pieces on the bench at the moment putting in new thrust washers. Take a look at the VTR website for some A-overdrive information, as well as the Buckeye website - good stuff both areas.

It does not sound electrical, so low fluid/plugged filter could be it.

Without tearing everything down it is pretty easy to remove the bottom plug and get access to the filter. These drives are meant to get to 400-450 psi for engagement, you can check the health of the oil pump by attaching a guage to the od - Jay Holecamp sells a nice setup for that purpose, there may be others as well.

 

[Geo Hahn]

...The ride home was a little slower driving in 4th no over. But 55 on those 2 lane roads was not all bad...

I flog my TR3A (no OD) the same way I drive the 4 (w/OD). The TR3 doesn't seem to mind cruising at 75 and moving into the 80s when needed ('But officer, I really needed to go that fast').

 

[TR3driver]

Fluid level sounds most likely to me, so check that first.

Then I would not rule out electrical, since I'm having a somewhat similar problem at the moment that I know IS electrical ... the contacts in the OD switch on the dash have apparently gotten dirty (maybe something about being parked outdoors every day for 20 years or so) and sometimes the OD is very lazy about engaging. The reason I'm confident it's the switch is because I can wiggle the switch around and it will go into OD.

I think my next step would be to measure how far the valve ball moves, as I've found that to be a common trouble point. The factory method of adjusting the solenoid linkage assumes that there is no wear between the cam & valve stem, but they do wear over time and make the "hole in the lever" method inaccurate. When the adjustment is right on the edge, it can cause lazy engagement.

Then I'd get out the pressure gauge, if you have one. I'm sure Jay's kit is fine, but just to be different I made my own adapter on the lathe.

The A-type has only a low presssure screen, and it's coarse enough that it only catches large chunks of debris. I guess it could be "gummed up", but I've never seen one that wouldn't pass enough oil to operate the OD even after a failure that loaded the screen with chunks. Also, getting the big plug off without a special tool and without damaging the plug is kind of tricky. So personally, I wouldn't bother checking the screen until after the pressure gauge showed a pressure problem. But it's your choice obviously (especially if you have the tool).

 

[Brosky]

When I was going through my parts to sell on eBay, I came across a manual shift lever conversion with a cable to operate these O/D's with a second stick shift lever on the floor. I got it from a guy on eBay a long time ago and never got around to playing with it. I know it's a shameless plug, but I really want to get my basement shelves cleaned off.

 

[TR3driver]

Paul, did that appear to be a factory gizmo, or some home-brewed kluge? If it is factory, I'd like to have it just to add to my curiousities shelf.

 

[TR3driver]

The TR3 doesn't seem to mind cruising at 75 and moving into the 80s when needed

I think we all have different comfort levels, which isn't necessarily a Bad Thing. The PO of my TR3 had installed a 4.10 axle without overdrive, then I installed shorter tires on top of that. It just didn't seem happy turning 4000+ rpm to keep up with traffic. But now with the OD installed and some more miles on the engine (plus some new rod bearings), it seems perfectly happy even out beyond redline.

 

[vivdownunder]

I came across a manual shift lever conversion with a cable to operate these O/D's with a second stick shift lever on the floor.

Manual overdrive engagement was used on very early TR2's until the solenoid with push/pull switch came in.

Regards,

Viv.

 

[TR3driver]

Manual overdrive engagement was used on very early TR2's until the solenoid with push/pull switch came in.

Are you sure about that? It doesn't seem to be mentioned in any of the books I've read, including Piggott, the factory workshop manual or the SPC. And I'm pretty sure I remember seeing the pull switch on the dash of TS1LO.

Perhaps you're thinking of the Francorchamps?

 

[angelfj1]

Like this, identified in the documentation as an early TR2 gearbox/OD. However, I must admit to never seeing one of those engagement levers in a TR!

 

[Minesweeper]

I had the same problem last year, and it turned out to be the solenoid. Fortunately a J-type solenoid refurb is an easy 10 minute job once you remove it from the overdrive. There'e a great tutorial with pictures on the other forum, along with part numbers for the thin wrench and o-rings needed. Nevertheless, after checking fluid, screen and filter, I would check electrical as Randall suggests. Easy enough to do with a test lamp at the bullet connectors in the passenger footwell area on top of the transmission tunnel, and then at the solenoid. If that shows that the switch is working and the solenoid is getting power, I would move on to refurbishing the solenoid. Personally, I would save the pressure test as a last resort.

Scott

 

[TR3driver]

Like this, identified in the documentation as an early TR2 gearbox/OD. However, I must admit to never seeing one of those engagement levers in a TR!

Which documentation?

The knob at least looks like what I've seen pictured for a Francorchamps coupe. The Francorchamps coupe was built by Imperia in Belgium from TR2 components, but my understanding was that the Belgians modified the shift linkage along with many other details.

But I just found where Bill Piggott mentions that they also used that arrangement in some TR2s that were assembled from the same CKD kits from Coventry. So I guess that explains it, although oddly enough he claims it involved a Bowden cable.

 

[Brosky]

The one that I have is a shift style cable attached to a shifter rod with a bellcrank of sorts and is NOT the one shown above. I'll post some pics tonight or tomorrow.

 

[TR3driver]

If that shows that the switch is working and the solenoid is getting power, I would move on to refurbishing the solenoid.

The A-type overdrive used on TR3s is quite a bit different than the J-type in this area. The J-type solenoid incorporates a low pressure hydraulic valve (with O-rings that can be replaced); but on an A-type, the hydraulic valve is way over on the other side of the OD. The solenoid is purely electro-mechanical.

It is possible that your problem is bad contacts inside the solenoid, but they aren't usually considered serviceable. And if that is the problem, it will be obvious once you get the transmission tunnel off and re-test, since the lever won't move. You can also usually hear the "clack" if you try operating the solenoid with the engine not running.

 

[GilsTR]

The "Redhead" has 4:11 gears....and with the overdrive not
working...I just cruised along at 55mph taching 3000 rpm.
A nasty rain storm dropped in on us...2" today...1" tonight
and 1" tomorrow. Will take a couple days...but will get it
up on the rack and check things out...and post then. Really
appreciate all the help here. Gil NoCal

 

[Brosky]

This is what I have. I really don't know what is is designed to fit or how it works with the connector on the end. I have a set of installation instructions, but I never got around to even attempting to install it. It wasn't until I started digging through my old PayPal receipts that I found the one for this and went digging through the boxes to find it.

 

[TR3driver]

That is interesting, Paul. Looks like a homebrew to me, but a very well done one. Are there any provisions for automatically disengaging OD in reverse?

As I'm sure everyone knows, trying to back up with the OD engaged will do some serious damage to the OD.

 

[Brosky]

Randall....I think that the only thing that will be automatic is the noise/damage that will happen if you forget to disengage it..........

 

[angelfj1]

Like this, identified in the documentation as an early TR2 gearbox/OD. However, I must admit to never seeing one of those engagement levers in a TR!

Which documentation?

The knob at least looks like what I've seen pictured for a Francorchamps coupe. The Francorchamps coupe was built by Imperia in Belgium from TR2 components, but my understanding was that the Belgians modified the shift linkage along with many other details.

But I just found where Bill Piggott mentions that they also used that arrangement in some TR2s that were assembled from the same CKD kits from Coventry. So I guess that explains it, although oddly enough he claims it involved a Bowden cable.

If memory serves, it was from a European TR Club site, either French or Belgian.