Austin Healey 3000 Gearbox and Diff Fluid Change

[@tjm3900]

Good video ! Triumph did have a drain plug in the diff on their earlier models like the Herald. It is a good idea to add one. A pad can be seen where the plug was sited. After 50 years of so the original oil will be contaminated if only by moisture which will sink to the bottom, if left. It is possible to tap for a drain with the diff in place on the car, just be careful to flush out any swarf out before finally filling the diff.

[@midwestmotoring]

I do kind of remember learning that some of the Triumphs had the drain plug. I've drilled the diffs in my GT6 and the Spitfire to include a drain plug. It just makes so much sense to have it, though that's more important for some people as others might not drive their cars more than a couple hundred miles in a year. In cases like that, the fluid might last a decade, and changing fluid might coincide with pulling the diff to change dried out seals anyway. Anyway, totally agree with you! Thanks for the comment!

Very impressed with you guys! Ok, can you do a video of the maintenance ( where to find grease joints, checking fluids, etc) of that AH 3000 mkiii?

[@midwestmotoring]

Definitely. That's a good idea. I'll need to get the Healey back from storage first though....

[@mangomcb]

Thanks for the excellent videos. Your vid on replacing the clutch master and slave cylinders was most helpful, HOWEVER, on my BJ8, working on jack stands, even with the tunnel removed, was a nightmare. Having worked on my own cars, especially the Healy, for over 40years I have never had so much trouble replacing two simple bolts! Whether from the top or the bottom of the car the angles needed to properly align the threads were ridiculously difficult. My old human hand just couldn’t contort the to positions needed to catch the threads. I am embarrassed to admit that it took me 4 hours to finally, properly align and tighten those two slave cylinder bolts! I think unless you’re a double-jointed monkey, a stand-up car lift would greatly help in achieving the angle you need to replace those babies! Classic British Engineering design…but l love my Healey anyway!! Chuckmcb

[@mangomcb]

Sorry…this comment was in regard to your excellent video on clutch cylinder repair..all your videos are great and much appreciated! Chuckmcb

[@midwestmotoring]

I hear you. Some things are just a pain to reach on these cars. I had a hell of a time just putting the bolt back in at the bottom of the generator.

[@k144kev]

Good job again very well explained. Out of interest as well as my mk3 spitfire, I have a wolseley 4/44 1955 that has a large rubber grommet in the gearbox tunnel and a dipstick just like the Healey's. I always show people as it cool pity other cars do not have them Kev Sunny South West Devon UK👍🇬🇧

[@midwestmotoring]

It likely has to do with the gaps between maintenance. In the Spitfires, the shop manual recommended 90w gear oil and "topping up" every 6,000 miles. I haven't found a spec for how often it should be changed out, but it seems like the design life of the car was less than the maintenance intervals.... so infrequently. The Healey on the other hand, recommended topping up every 1,000 miles and changing the fluid every 6,000--likely because they recommended using 20w50 motor oil rather than gear oil, so the maintenance would need to be carried out more frequently. Still... you're right that it's much cooler to have a dipstick than a plug on the side!

[@soup1448]

Nice job and good explanations.

[@midwestmotoring]

Thanks!

[@rbittmann1642]

There was no mention of the diff. Lubricant type weight brand - what is ideal for the Healey? Is Redline MT90 appropriate?

[@midwestmotoring]

Redline does not recommend MT90 in a Healey, though it would work fine in some other differentials (like in a Triumph TR6). Apparently, it has something to do with the offset of the gears. Anyway, the Redline 75w90 will do fine, and it's what I run in my Healey. It's a GL5 fluid, but is buffered to be okay with yellow metal. Actually, most GL5s are buffered nowadays and won't corrode yellow metal. The reason they're not good in many manual transmissions has more to do with the friction modifiers and less to do with damaging parts. In other words, it's not that they'll eat the metal... they're too slippery so the synchros won't grab. Incidentally, that's why 4T oils are used in motorcycles--they're slightly "grabbier" than ordinary engine oil because the gear train shares the same sump.

[@allenslocumb8278]

How often do you do that? I only did it once in my B b/c it was in storage for a decade so I changed everything. Never done it in my TR6 and not idea if PO ever did it. Probably should do it. But then how often?

[@midwestmotoring]

I'd say every 3 to 5 years since the oil will degrade over time, but there will be a maintenance schedule to follow in your shop manual too depending on how much you drive it.

New 1968 BJ8 owner here...is the gearbox and differential fluid the same reservoir? Same Red Line MTF fluid?

[@midwestmotoring]

Hello! No, the gearbox and diff are in separate locations and also do not use the same fluid. Redline calls for MTL in the gearbox, though I use MT90 in mine, which is slightly thicker and less prone to leaking out. MT85 slots neatly between the 2 and could be a good compromise. The differential needs more extreme pressure additive because of the high offset of the gear teeth, and GL5 is the way to go here. Most of these will not be corrosive to yellow metal these days. Just be sure to change the fluid periodically as they do go bad.