1964 TR4 - Part 7 - Diagnosing The Overdrive

[@iceman9678]

Merry Christmas. We watched you video first thing this morning!

[@GalvestonCountyMike]

Splendid video Elin! Between watching your dog wake up from a nap, and the heater fan turning on, it all makes for a fun and educational video! A Merry Christmas to you and your family! Cheers from Texas!

[@matthewharlowehrscyclespor668]

Happy Holidays and a Merry Christmas from Lake Stevens, Washington USA

[@alexanderduncan4302]

I usually put a thin smear of hylomar on each side of the clutch cone Regards Sandy 🔧🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@edwardkendall3905]

I’ve watched all your transmission/overdrive videos and each one has an extra nugget of information. Thanks, and best Christmas wishes to the cast (you, Nick and Rusty) and your family.

[@seanwalsh999]

That's why you buy the pressure gauge with the hose attached, to avoid the situation you found yourself in. Great show, thanks for posting.

[@paulresca6681]

Very well explained. Thanks

[@alanm.4298]

Merry Christmas to you and your family, Elin! Interesting video for me, as I've got an A-type that needs similar testing before final installation in my TR4. I will need to build a test bed like yours and was pleasantly surprised to see that for testing purposes driving the output shaft is functionally the same as driving the gearbox input shaft. You mention using non-detergent motor oil (racing oil) in the overdrive gearbox (which "shares" oil with the OD unit, so requires a bit more than a non-OD gearbox). That agrees with everything I've been told. The OD operates via hydraulic pressure and any detergents in the oil will cause foaming that introduces air into the system and interferes with the function. At least that's how I've heard it described. (Probably applies to non-OD gearboxes too, since oil foaming caused by detergents might reduce the lubricating properties... Besides, since the is no combustion like in an engine, there's no need for detergents in a gearbox.) It also is important the oil have no sulphur content, due to all the brass bits (synchros, etc.) in the gearbox that sulphur would damage. I believe the Triumph TR4 specifies 90W gear oil for both non-OD and OD gearboxes. As I understand it, 20w50 motor oil has about the same viscosity and can be used instead. John Esposito at Quantum Mechanics, who specializes in repairing these old Laycock OD, has suggested that freshly rebuilt OD might do better on lighter oil such as 10w40, but later with some mileage on them can switch to a mix with increased viscosity or eventually go fully to the heavier oil. I couldn't see what weight oil you were using, so am just passing along what John has said in the past. Essentially, he is suggesting you can "tune" the OD performance a little with the viscosity of the oil. Do you remove the large brass plug in the underside of the A-type and clean the filter in there? If so, do you have a special tool for that purpose? Cheers and thanks for the very informative video! 😎

[@malcolmlane-ley2044]

Merry Christmas Elin.

[@davidberlanny3308]

Look forward to watching this when the house is quieter!! Have a great Christmas Elin and Niko Feliz Navidad from Portsmouth England🎄🎄🎄

[@not-fishing4730]

Elin, I view it as part of the project that you have multiple orders of parts. I always seem to find something else to fix after I place an order for parts. We just do the best we can and hope for the best.

[@matthewharlowehrscyclespor668]

Great diagnostics. 👍

[@pda49184]

Great stuff Elin.. Hope you do better then me with your parts order ! I always missed something 😄...

[@alexanderduncan4302]

Called locking wire in the UK & safety wire in the US Regards, Sandy 🔧🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@davidfidler1174]

Good video Elin. May I suggest this would be a good time to add a reversing light switch? If the customer would like one of course. A tip I learned from Philip Allen of Britcars fame, TR4 clutch shaft bushes are phosphor bronze, TR6 ones aren’t and they wear faster. He always used TR4 bushes in a TR6 gearbox. No problem in this case, but for future reference if you have to replace them on a TR6 box.

[@RustyBeauties]

Thanks Fid! I didn’t know that.

[@Patrick-Inc]

👍🏼👍🏼

[@tjm3900]

I am not familiar with A type O/D but I understand they incorporate an accumulator. Perhaps this was why the pressure is not dropping when the O/D is turned off ?

[@kge420]

Hello!

[@Kamphausen]

To support the OEM clutch fork pin i simply bored a hole thru the fork and mounted a spring pin en.wikipedia.org/wiki/Spring_pin for some cents....can be done in situ