J-Type overdrive lubrication

[Chris Attrill]

All. I asked the transmission specialists who rebuilt my overdrive last September (before I bought the car) for advice as to overcoming my sticking overdrive (the car has done barely 700 miles since the rebuild, last September). Amongst other good advice they recommend NOT using EP 80 etc., but a non-synthetic (mineral) 15-30 engine oil. This, apparently, is ok for the gearbox and works better in the J-type overdrive than the high-pressure stuff.

I replaced the oil in my gearbox today and took the car for a run - although the problem hasn't completely gone away, it is somewhat improved. I'll give it a while before I'm completely convinced but the proof of the pudding...……..

I'll be interested to see comments from the experts out there.

Rgds

Chris

[thebadleys]

If they rebuilt it would they not have made that recommendation to the previous owner ?

My MGB with a Laycock overdrive (cant remember what model letter ) engine oil was the recommended lubricant, 20 - 50 multigrade, it had been EP 90 but changed to 20 - 50

I remember some telling me that he had added Molyslip to his overdrive, complete overhaul not to much later !!!

Nigel

[sujitroy]

In US triumph owners say to use Redline MT90 . It's synthetic and not cheap.

https://www.amazon.com/Red-Line-50305-MT-90-Oil/dp/B002INX20C

Can't you take the OD back?

Without too much specifics on your sticking OD problem, I think you have an iffi solenoid.

Sujit

[Guest]

All. I asked the transmission specialists who rebuilt my overdrive last September (before I bought the car) for advice as to overcoming my sticking overdrive (the car has done barely 700 miles since the rebuild, last September).

Amongst other good advice they recommend NOT using EP 80 etc., but a non-synthetic (mineral) 15-30 engine oil. This, apparently, is ok for the gearbox and works better in the J-type overdrive than the high-pressure stuff.

I remember hearing this from that man at Dennis Welch.......!
"the reason why my (WELCH repro) gears failed is because I failed to use engine oil in the gearbox."
yea yea yea.
Heard it all before! two returns on warranty later.....(FROM FRANCE, and it's not fun to remove a gearbox from a Healey!!!!! TWICE)

The solution?
I got Hardy engineering to rebuild the Healey box, (heard good things about their Healey boxes),Ie. everyone in the trade knows Dennis Welch have been selling selectors that jump out of 2nd gear for decades, and his recon laygears are total soft butter...followed by utter bollox as support for their stuff, so as not to have to honour warranties.

Result?
The Hardy engineering box is and has always been perfect, no problems in the 15 years that has gone by since on a modified 100/6.
The whole incident cost me about a grand in time and trouble.

I haven't forgotten it, much like the dud E type V12 auto box someone in the UK sold me, which failed after 200 miles (changing that involves removing the engine again!).

Now,
I have been building boxes for the GT6 for more years than I can remember, and it was me that did the J type conversion/improved mainshaft mod originally.
I even used them in motor sport.
We did the same in Germany.
I just supplied a TR6 J type box to a guy in Osnabruck, (which apparently nobody else could rebuild properly)**.

I have ALWAYS USED EP90 in overdrive gearboxes as this contains an additive designed for all hypoid gears (involves intense sliding and sheer action).
For motorsport I got a mil spec oil from Cofran which cost a fortune.
Something similar is available from MOTUL - their special full synth oil, and Mobil used to do a special similar SHC.
Ignore people who say EP90 is bad.
It's not.

Engine oil has no such additive, and has other nasties in it.

Originally the overdrives had a sort of SAE30 mineral oil that had very low viscosity particularly from cold, where EP oil is very thick indeed, so it is in fact possible to use Dextron.

If your overdrive clutch is sticking, the lesson is:-

Don't believe anyone anymore.
The likelihood, the clutch has been made wrong, because the lining has to be within a few minutes of a degree true to the brake ring and annulus.
If it's not it either slips and dies, or sticks nicely solidly in.
Been there, done that.

**MORE REPRO CRAP.
I spend my life fixing it nowadays.