Overdrive woes...

[Guest]

I got my newly rebuilt J-type overdrive installed in my TR6, and it don't work.....

The rebuilder is working with me on this. First the aftermarket overdrive lever switch (piece of crap)was built backwards, up is off, down is on. And, the switch barely makes good contact. (He's sending me a new one) It makes the solenoid go on, sometimes or sometimes not. I rigged a remote starter button to the solenoid and got it to click on every time. The darn thing just won't go into overdrive. All wiring is correct, install is right-on. He's sending me a new solenoid. He also told me to "bleed" the thing for possible airlock at he bolt beneath the solenoid. Ya'll confused? Try sitting with me, 80 degrees and Mardi Gras is this weekend, wanted to take a drive to N.O.
Anyone have a guess as to what could be wrong? The builder is as concerned as me and I am sure he will walk with me on this. Just frustating...

Bill

 

[Guest]

ps,
It did go into overdrive a few times so I know the thing works.....

Bill

 

[MDCanaday]

Dr Bill, I know that feeling, that sick sick feeling. These beasts work by building up oil pressure in a chamber and upon its release the oil forces pistons to overcome considerable spring pressures engaging a clutch........long and short, if the critter cant get the oil pressure in the chamber high enough(and maintain it)it wont work.Did you use 75wt oil????? try 90. but I fear your pump is weak and may need refreshed.
MD(mad dog)

 

[Guest]

Mad Dog,
The reputable fella that rebuilt the system for me INSISTED that I use 30 wt non-detergent oil, in spite of every thing I have read. I told me to "bleed" the air out of the pump by loosening the bolt under and in front of the solenoid whilst the tranny was engaged (on jacks, of course). I am not worried that he won't make it good, but just don't want to remove the beast again. What a nightmare! Actually taking it out is a snap, putting it back is like standing on your head and stacking BB's, with an elephant on your chest.....

Bill

 

[Dave Russell]

I believe that 30 wt engine oil is suggested by the original overdrive manufacturer. Some car manufacturers suggest engine oil & some suggest gear oil.

A lot of the confusion comes about because of the two different viscosity rating systems that are used for gear oil & engine oil. Engine oil viscosity is rated at 210 degrees F. Gear oil is rated at 100 degrees F. Therefore 20 wt engine oil is about the same viscosity as 75 wt gear oil. There are different additives in the two oils but I won't go there.

There are several past threads arguing the merits of different transmission fillers.

 

[Guest]

Thanks Dave,
At least the elephant is off my chest....

Bill

 

[Dave Russell]

DB,
It is possible that there is air in the hydraulics.

Instead of putting the car on jack stands it would be safer to disconnect the front U joint behind the transmission.

Check here for some interesting reading, especially the sections on the J type overdrive. Maybe your transmission guy would even like to read them? Although he probably knows it already.

https://www.buckeyetriumphs.org/index_technical.htm

Good troubleshooting,
D

 

[vagt6]

Dr. Bill, I feel your pain. I have a Quantummechanics Jtype that doesn't work properly. Mine always engages in OD, but when the car gets fully warmed up, it won't disengage until I come to a stop (or until about 5-10 seconds pass). I've checked the electrics carefully, it's not electrically-related.

It's tolerable and the unit works OK except for the above problem, but it's irritating, especially since I paid over $1,400 bucks for this thing (also, the kit contained the wrong wiring harness -had to fabricate one from scratch--, no mount adapter, and other problems). I received no offers of help, or suggestions about how to fix it from Mr. Esposito after Emailing and phoning several times.

I'be been told that my problem is related to the solenoid "sticking" and may be fixed by honing the sleeve in the solenoid where the piston slides back and forth. At least that's what I've been told.

I understand that about 80%+ of the problems with Jtypes are related to electicals. And, electrics are the easiest to troubleshoot. Just check your electrics carefully before you start tearing the unit down.

Also, check out the attached, excellent piece on Jtypes: https://www.buckeyetriumphs.org/technical/JOD/JOD2/JOD2.htm

Also, see this one, too: https://www.vclassics.com/archive/laycock.htm

I hope you make it to Mardi Gras! Please let us know how you fix it, and good luck! REgardless of this temporary problem, you're going to LOVE your Jtype.

 

[Carmine]

Dr. Bill,
I had a problem with my solenoid sticking in the on position. Removing it and honing the bore cured my problem. It takes a special thin open ended wrench to take the solenoid off.
Before you do that, maybe you should check the fluid level in the transmission/overdrive unit. After rebuild and first useage, the fluid level may have dropped to the point where it will not develop enough pressure to operate.

Also, I think the activation switch on the steering column is supposed to move down to turn on and up is off. That's the way my J type operates.
Good Luck

 

[Guest]

Guys,
All of your info is very enlightening and helpful. More questions, though. First, the idea of disconnecting the drive shaft makes sense as it would be safer than running the car on jacks. Would thrust and resistance make any difference in the operation of the overdrive,i.e., wheels hooked up? Also, I only have one set of Clevenuts, hate to use Nyloc to bolt the shaft back on. Perhaps a little more Loctite...
If, indeed, I do back the drive shaft down, probably really need to monitor the revs with no drag on tranny.
Bleeding the "possible" air in the pump is accomplished by loosening the screw under the solenoid a bit. How much and how long and what should I look for coming out? Oil? Air?
He sent a brand-new solenoid today, replacing the one that he put on the rebuild. The one that came with the rebuild was not new looking at all. Hmmmmm.
Interestingly, the original manuel that came with the car ('73) said the up position was "on" and down was "off". The second switch he sent (along with the nice, shiny solenoid) was just as backwards as the first. What the hey...

Went to Mardi Gras in the family car and caught move beads than I could carry! It seems that "flashing" by buxom young ladies to get more beads is common place. Oh how I miss the Sixties....

Dr. Bill

 

[MDCanaday]

Dr Bill, the A type had a screw in the top that when removed let a pressure gage tap into the output of the oil pump.This (if the same) would be the bleed spot.
As for oil, try at least 50wt nd engine oil. that is what MG called for. I have spoken with several builders who all disagree on this issue, there is ,I think, NO consensus on what is best to use. Oils have changed a lot since the beasts were concieved, and it is very possible that the factory would now recomend something very different indeed!!!
MD(mad dog)

 

[Dave Russell]

DB,
The resistance of the differential & wheels should make very little difference. Use your judgement on the nuts. In theory, if they are properly tightened they really wouldn't need locking. Use Loctite if you are not sure.


Bleed the OD just like a brake cylinder. loosen until something comes out. If it is air continue. If it is oil wait a few seconds more to make sure that there is no more air.
MD,
The J type OD layout is quite different from the A type.
D

 

[JM1NA]

The J type in my spit 1500 wouldn't disengage after a long run either. Never did figure it out, but it was a nice option... when it felt like working....
Hope you get it sorted out. That's an expensive
option, but once you do, you're engine's bottom end will love the extra gear.

Ron

 

[vagt6]

I installed the column switch on my '70 and it is "on" with the switch in the down position. My switch, which looks like a longish turn signal lever, is on the LEFT side of the steering column.

Dr. Bill, please keep us posted on your progress. Also, it looks like it's raining on your Fat Tuesday, so maybe you lucked out!

 

[Guest]

Well, I finally got the bugs worked out in my new overdrive. John and I worked it out over the phone. There was apparently a very small piece of trash in the solenoid workings so I took it back out and cleaned the area really well with some brake cleaner and an air gun. Voila! Works like a charm.... It would go into overdrive and not come out. Now it works perfectly. Can't wait to pass that Shell station that I always had to stop at on the way to New Orleans. We are having our annual British Car Day with the N.O. club on Mar.20 and I have lots to do to get my baby back into show condition.

Bill

 

[Guest]

Oh, and I did add that little LED light in the dash. Kinda nice to know at a glance when the overdrive is switched on.

Bill