A Type Overdrive

[JerryVV]

There are 8 springs that fit on posts attached to the sliding clutch assembly. Some have red ends and some have yellow ends. Which color goes on the outside 4 posts. I know the long springs go to the outside but I'm told the new ones I've ordered are the same length but are different wire diameter and 4 are painted red and 4 are painted yellow on their ends.

 

[TR3driver]

Dunno about red & yellow; the Laycock manual says they should be red & blue. But the ones with the thicker wire go on the outside, as the inner ones have to compress farther.

 

[JerryVV]

Still chasing my problem and think I may have reversed the springs when I replaced the sliding clutch causing spring binding. Pulling the gearbox tomorrow and next Saturday pulling it apart, correcting the expected problem and re-installing in the car. I think I can get it out myself but will have help installing. I really don't much like doing this anymore. Used to do it myself in a day. Too heavy now to do myself.

Thanks Randall.

JVV

 

[TR3driver]

Yup. About the only good thing about getting older is that it beats the alternative! I put mine in by myself last time, but it wasn't any fun at all.

 

[TR4nut]

My club buddy did exactly that (switched springs) - makes for a very weirdly operating overdrive from what I remember. The way he figured it out was to compress the springs to where they bind and measure their bound length - then you could see the difference in the springs. Just a small piece of all-thread and a couple of nuts did the trick.

 

[JerryVV]

Mine would try to engage but would not fully engage and kind of freewheel untill the revs increased enough to engage the roller clutch and then drive the transmission as normal. Pressure was fine and adjustment as well as solenoid are OK. It must be my mistake. But if not then what???

 

[TR4nut]

I'll bet you have it figured out, but unfortunately its a tear down. Here's a link to what my buddy described on the FOT site:

OD Symptoms

Slipping OD - final outcome

 

[Don Elliott]

Jerry - Is it possible that the new springs with the unusual colours are for a type J overdrive for a later TR6 ?

 

[JerryVV]

Nice to hear from you Don, trust all is well with you.

I guess anything is possible but I rather doubt it. They were bought by P/N and were supplied by Overdrive Spares in England to TRF. I would hope that those 2 organizations would get it right. I had another set from many years ago that were NOS from a dealer close out and they were red and yellow as well. I need to look at more information and try to run all of this to ground.

 

[TR4nut]

Jerry-

You didn't talk too much about pressure, did you observe the pressure the same time you had the issues with the operation? I was thinking if you aren't building up pressure very quickly you could drop to a low pressure situation that takes time to build back up - wouldn't that give you a little slipping/strange behavior before the cone clutch was locked in place?

Randy

 

[JerryVV]

Randy

I don't thnk the pressure is a problem. I measured it at 350 (it's the large piston type OD)and later shimmed the accumulator piston with 2 .060 washers. It's closer to 380 now. Pressure built quickly and recovered quickly (maybe 2 seconds)
I'll know next Saturday when it gets pulled and broken down.
Used Redline MT 90 as many folks have recomended.

I thought it might be an adjustment issue so I drove it without the solenoid and manually engaged the OD. No difference. I was very surprised how much effort it takes to move the lever and hold it in. Don't know if that's normal but it did seem like it was too hard to engage. I've never done it manually so I have no comparison to make with a properly operating unit.

JVV

 

[TR4nut]

I tested mine manually and it does take some force to move that operating valve up - you are basically trying to push that ball bearing against the reservoir pressure when you engage so it does have pretty good resistance.

 

[JerryVV]

Yesteray with the help of 2 good friends we pulled the Transmission out and broke it down. When I rebuilt the transmission several years ago I didn't like the condition of the sliding clutch member. During my recent restoration of the car I decided to replace that clutch with a better used one. For whatever reason that was the problem. The eight springs were installed correctly but the cluch was jambed somehow. We decided to put my original clutch back in. Reassembled, installed and took a brief ride. Works great now.

No real idea why the replacement clutch was jambed and on taking a second look the linings didn't look so bad afterall.

All is well.

 

[TR4nut]

Jerry-

Make me wonder on how much wear is tolerable on these setups. I have a few of the clutch members, and the linings look decent, at least there is material well beyond the rivits. But we trial fit a couple of them and found they were at the high end or beyond the recommended clearance. Don't remember what that clearance was, but there is a factory recommended range for the difference between engaged and disengaged. Maybe that one you had is a little thinner?

Randy

 

[JerryVV]

Visually it was hard to tell any difference. What we found was the clutch was jambed. It looked like one piston may have stuck and cocked the clutch to one side. When we looked at the pistons there were no problems that we could identify. To be safe we reinstalled the clutch I took out and it worked fine. I'm sure the clutch will be looked at carefully to see if anything could be identified. I got the part from a friend who rebuilds these. He'll figure it out if there is anything to be found.

 

[JerryVV]

Final post on the subject. Upon close inspection of the clutch assembly a circlip had come out of it's groove and moved forward a bit. That allowed the clutch to not fully engage and explains why things were jambed upon disassembly. No idea how the circlip came loose and will never know.

 

[TR3driver]

Something you might want to look at, Jerry, is how far the pressure relief ports are uncovered when the main accumulator spring hits coil bind. I also had that circlip come out of it's groove, and I believe the reason on my unit was that I had shimmed the spring until it would not allow the ports to be fully uncovered. The pressure tested OK on the bench at relatively low rpm, but apparently went much too high at high rpm (and probably on a cold morning to boot).
In my case, the damage from the circlip being forced out of the groove was fairly obvious; but yours might not be so obvious.

 

[JerryVV]

Interesting thought. My OD did not work from the get go when I re-installed the trans and engine during the restoration. It worked when removed. The only thing that I did was replace the clutch assembly with what I thought was a better unit. I have now shimmed the accumulator spring in an attempt to fix the problem before last weekend. So I conclude that the circlip was not moved out of place because of shimming the spring. If I develop the problem again I'll know where to look. I added .060 total. Everything that I read would say that wouldnot create coil bind on the large spring accumulator.

The shift into OD was firm but not harsh under mild load. Actually very smooth, no hard bang into OD. Coming out of OD was the same again under moderate load.

Using Redline MT 90 too. I always used GL4 90 weight. MT 90 is much less viscous feeling. Im off to VIR in a week for their Gold Cup, so will have a nice ride through WV and VA mountains. Hope it doesn't rain. Need a break.