• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Embarrassed to ask: Transmission/Gearbox filler location on BJ8

Share this page

S

shortsguy1

Jedi Hopeful
Offline
I have been slowly changing out all the fluids in a 1966 3000 BJ8, but am stuck with changing the transmission (aka gearbox) fluid. I honestly don't know where the fill location is. The Mk III Driver's Handbook says it is "situated in front of the gear lever" under "the inspection panel in the top left-hand side of the gearbox cover." Kenneth Ball's Austin Healey Owners Workshop Manual says "the dipstick is combined with a filler plug located on the righthand side of the gearbox cover." Perhaps the left hand vs right hand issue relates to whether the car is left or right hand drive (mine is left hand drive). Even if I know which side of the gearbox cover (aka transmission tunnel) it is located on, I still don't fundamentally understand how I get to the inspection panel.

According to the Workshop Manual, I will have to pull up some carpet (they call it a floor mat) for this job. Does anyone know how this carpet is normally attached (glue, screws, gravity, chewing gum???). I don't have access to the car right now, and try to figure out all the details in advance. I will have access to the car for a few days over Thanksgiving, if the carpet is easy to remove, I should have time to take care of this. Sorry if this is a dumb question.
 
Shortsguy--

I have a BN1 with a Smitty's 5-speed conversion so I cannot be of any real assistance other than to point you towards the illustration in the Moss catalogue which shows the dipstick/fill hole to be on top of the gearbox:

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28881

In my experience when one must access a maintenance point under an LBC transmission cover--a prop shaft grease fitting or the like--there is usually a large rubber plug that is easily removed once one peals back the carpeting or floor mat which is hopefully NOT glued down.

BTW I seem to recall that since you must drain oil from both the transmission and the OD there are two drain plugs that you will have to pull.

The fact that no one has replied since your post from 8 hours ago makes me wonder if any of the BJ8 owners on the forum have ever changed their transmission oil!
 
There maybe a flap on the carpet drivers side tunnel . If not lift the tunnel carpet from drivers side remove the rectangular rubber plug from the tunnel and bingo there's the dipstick . When you drain the fluid remember to drain the overdrive and pull the filter and clean it . It's located where the round brass plug is on the OD . It's about 3" diameter and you need a bearing hook wrench to unscrew it . Fill it all with 20/50 and your good to go .. Do not use any transmission snake oil stuff as you will not do the OD ANY FAVOURS AS IT HAS A FRICTION CLUTCH IN IT .
 
On a centre shift gear box as found in the BJ8, the dipstick is on the top left side in front of the gear lever. On a side shift box it is down on the right hand side of the tunnel. The tunnel carpets have to be lifted to access the inspection panel. If correctly fitted the carpet is held in place by a type of press stud where you lift the top to release the fitting from the stud.
 
Just another note:
If the previous owner glued the carpet to the transmission tunnel , you will have to remove the entire tunnel to get access to the filler plug. Normally the carpet can be unsnapped and pulled back to give you access.
 
One more note: Know a lot of folks use 20/50 oil but I would recommend either 30 wt non detergent or 40 wt non detergent oil, the emphasis on non detergent. If you have any trouble finding it at a local auto parts store, you can get it on Amazon.
Regards
Mike
 
Thanks everyone for your helpful replies. I think the carpet is original, so hopefully it is not glued down. There is no flap unfortunately.

I was unfamiliar with hook wrenches until I looked them up right now. I think I recall a thread where someone (Keoke?) suggested tapping it open with a brass drift if you don't have the correct tool. Is there an inexpensive, but reliable method to remove that cover that anyone can recommend?

I bought the fluid for this job months ago, because I thought I would churn through a bunch of jobs quickly. Alas, it has been a bit slower than expected. One step forward, and two steps back. Okay, to be fair, maybe it has been one step forward and one step back. With every job, I find new tasks that need to be completed. Anyway, I bought 3 L of Redline MT-90 which I plan to use for this. Hopefully 3 L is sufficient. And hopefully a bunch of leaks don't present themselves. Because I haven't been able to check the current fluid level, I really don't know if the tranny has existing leaks or not. I will be curious if I can tell a difference with this fluid. I have no idea what is in there right now.

Anyway, thanks again for all the help.
 
shortsguy1 said:
Thanks everyone for your helpful replies. I think the carpet is original, so hopefully it is not glued down. There is no flap unfortunately


I was unfamiliar with hook wrenches until I looked them up right now. I think I recall a thread where someone (Keoke?) suggested tapping it open with a brass drift if you don't have the correct tool. Is there an inexpensive, but reliable method to remove that cover that anyone can recommend

Anyway, thanks again for all the help.
Click to expand...

The carpet flap is an aftermarket carpet option .
Big ass set of channel locks .
 
shortsguy1 said:
I was unfamiliar with hook wrenches until I looked them up right now. I think I recall a thread where someone (Keoke?) suggested tapping it open with a brass drift if you don't have the correct tool. Is there an inexpensive, but reliable method to remove that cover that anyone can recommend?
...
I bought 3 L of Redline MT-90 which I plan to use for this. Hopefully 3 L is sufficient. And hopefully a bunch of leaks don't present themselves. Because I haven't been able to check the current fluid level, I really don't know if the tranny has existing leaks or not. I will be curious if I can tell a difference with this fluid. I have no idea what is in there right now.
Click to expand...

3L should be enough to start, but buy another when you get a chance because the gearbox/OD WILL leak.
 
Is that MT-90 thin like 30-50wt motor oil or thick like 90wt gear grease?
 
MT-90 is a synthetic gear oil frequently recommended for these gearboxes. Supposedly, it can quiet down the synchromesh gears and make the gearbox smoother (whatever that means). I went back and found some BCF threads on its use from 10 years ago. I feel that if it had longevity issues, it would have come up on the forum over those 10 years.

According to the Redline website, it is a 75W-90 GL-4 gear oil. Because that viscosity scale is different than motor oils, those numbers correspond in viscosity to a SAE 5W40/10W40 engine oil. Here is the link:
https://www.redlineoil.com/product.aspx?pid=46

I will buy another quart the next time I need to get my Amazon purchase up to $35 to get free shipping. Thanks for the warning about the leaks. Your certitude made me laugh.

And I will keep an eye out for big channel lock pliers. I wonder if a pipe wrench would be too clumsy? Thanks everyone for the help. This forum brings together a remarkable group of people.
 
You can remove the overdrive plug using a screwdriver and tapping it with a hammer. Not ideal, but if you are careful its not a problem. Its not something you are doing every week.
 
If your overdrive works ok, then you have oil in your transmission.

I would strongly recommend you use the ND 30w oil previously recommended and not the MT90. The 30w oil can be bought at low cost from most gas stations, I use Warren ND30W. I currently have it running in more than 30 customers cars with overdrives.

The MT90 oil works well but if you don't have a leak now, you will do later. The MT90 will find the smallest of pin holes and will leak. Then when you change back to 30w it will also find the leak hole the MT90 found. Been there , done that.
 
Back
Top