J-Type Overdrive Solenoid Rebuild (Triumph TR6 here)

Most overdrive engaging issues occur with a sticky solenoid. Often times sticking in the on position when hot and won’t release which is dangerous. If stuck On never put car in reverse.
The solenoid controls a ton of pressure. They are very robust and expensive to replace. Typically the five o-rings need to be replaced to restore the solenoid plus a good cleaning.
The J-Type was used in later TR6 Triumphs replacing the earlier A-Type.
This overdrive was in Volvos also.
McMaster-Carr: www.mcmaster.com/products/rub...
The Orings you need are:
All BUNA 70.
Size 7. Qty 2 size 007 ID 5/32 OD 9/32 ID0.145" OD 0.285" Durometer 70A (Medium)
Size 10. Qty 1 size 010 ID 1/4 OD 3/8 ID0.239" OD 0.379" Durometer 70A (Medium)
Size 14. Qty 2 size 014 ID1/2 OD 5/8 ID0.489" OD 0.629" Durometer 70A (Medium)
Thanks. #diyhelp

[@KJs581]

I have 2 J types, one on a Stag, and one on a Dolomite Sprint, and both are too close to the body or exhaust to get a spanner on there to undo, so I got an old open end spanner and cut the end off (like a crow foot spanner) and welded that onto the other (handle) end of a single end spanner at 90 degrees, and that slides on. You can only turn it so far, but as you said, once it loosens from tight, can turn undone by hand. Same to tighten, it turns most of the way by hand, then the last little bit, spanner has enough travel to tighten.

[@DIYHelp]

Great idea. I have tunnel access also with an access plate but it’s a pain to get too.

[@bernardwarr4187]

Great job and information. Have you ever taken the roll pins out off the solenoid cover before?

[@DIYHelp]

Thanks. I have not. Just oil and filter cleans and solenoid orings.

[@arisarvanitakis5672]

Nice job! I have a question about o-ring sizes. The numbering, as appeared in the video, does not help to find out the correct o-rings. The size shall be expressed as internal diameter & thickness. Do you have this information? Also inside solenoid there is one more o-ring that seals the piston assembly from the solenoid. I had leakage exactly there.... Taking out the piston setup from solenoid is PIA and tricky! Not guaranteed always...

[@DIYHelp]

if you order the size I call out which is the WD size (water displacement) the correct size will arrive. Web address and all sizes:
McMaster-Carr: www.mcmaster.com/products/rubber/hardness~durometer-70a/o-rings-1~/oil-resistant-buna-n-o-rings-8/
The Orings you need are:
All BUNA 70.
Size 7. Qty 2 size 007 ID 5/32 OD 9/32 ID0.145" OD 0.285" Durometer 70A (Medium)
Size 10. Qty 1 size 010 ID 1/4 OD 3/8 ID0.239" OD 0.379" Durometer 70A (Medium)
Size 14. Qty 2 size 014 ID1/2 OD 5/8 ID0.489" OD 0.629" Durometer 70A (Medium)