Gearbox/Overdrive Removal

[BN6_2197]

Gents,

I want to refurbish the overdrive of my BN6. As I understood, I have to get the complete gearbox/overdrive unit out of the car for this, right? I am looking for instructions how to do it. Can I remove the unit from inside/above the car or do I have to do it from under/beneath the car?

Does anybody know a company in preferably in Germany or the UK that can do the job of the overdrive refurbishment?

Thanks in advance!

Regards,

Volker

 

[BobHaskell]

Volker,
The overdrive can be removed, leaving the gearbox in place, but I'd pull both. Gives you an opportunity to look at the clutch, flywheel, pressure plate and release bearing. Also easier to reinstall the OD to the gearbox out of the car. They have to come out from above; the chassis design doesn't provide the space to remove it from underneath. You will need to disconnect things from underneath, so put the car on a lift or jack stands. Suggest you get a workshop manual, if you don't have one already.
Support the rear of the engine. Remove the seats and carpet. Remove the gearbox cover after removing the gearshift lever. Disconnect the lead to the OD solenoid. Disconnect the speedometer cable. I'd remove the right angle drive. Disconnect the clutch slave cylinder from the bell housing, let it hang. From underneath, remove the two bolts that go through the frame to the rear gearbox mounts, the the tie rod and remove the drive shaft. Support the gearbox with a jack. Remove the rear gearbox mounts. Remove the bolts holding the bell housing to the engine. Note the location of the 2 'special bolts - align the bellhousing to the engine. With help from some friends, pull the gearbox back to disengage the input shaft and lift it up to clear the frame. Swing it to the passenger side and out the door. I use a sling to lift the back of the OD.
I'm sure someone will chime in with the items/details I left out.

 

[BN6_2197]

Bob,

thank's for your reply. That's a really good starting point. Maybe someone else from the community will add some stuff to your procedure.

Regards,

Volker

 

[dezand]

Gents,

I want to refurbish the overdrive of my BN6. As I understood, I have to get the complete gearbox/overdrive unit out of the car for this, right? I am looking for instructions how to do it. Can I remove the unit from inside/above the car or do I have to do it from under/beneath the car?

Does anybody know a company in preferably in Germany or the UK that can do the job of the overdrive refurbishment?

Thanks in advance!

Regards,

Volker

I recently pulled the gearbox/OD from my BT7 and I would add to Bob's information, that I also removed the driveshaft, just couldnt get the gearbox back far enough with it installed. I also did the same thing in using a small engine hoist to lift the unit out of the car.
In order to get the two slings closer to the center of gravity of the unit, I removed the windshield, which surprisingly only took 15 minutes. Plus the sling would come close to the windshield and I would not rather taking a chance on breaking it with a swinging gearbox. Depending upon where you will put the gearbox when it is out, for me I purchased a mechanics utility cart and used ratchet straps to hold it down while moving it around the garage.

 

[WHT]

Hi Volker,

As recommended by Bob (BN6_2197) and dezand, a hoist to lift the transmission from and into the car can make the job much easier for one person.

I would never recommend this to anyone (so ignore this because I am a Philistine by nature), but I made a very nice 4-inch by 4-inch contoured top cover plate for the front of the transmission tunnel using a replacement Kilmartin tunnel. It bolts to the original tunnel with 6 screws and is sealed with Dow 795 Silicone Building Sealant (construction grade sealant used to install skyscraper windows and boat ports). The cover plate contours match the factory tunnel perfectly and it looks very professional; and is as strong and ridged as the unmolested factory tunnel.

I watched several mechanics struggle trying to lever an AH transmission in-place on You Tube (the video never actually showed them successfully fitting and aligning the bell-housing). I also looked at many pictures of beat-up transmission tunnel openings online before removing and installing my transmission.

The first removal and installation without the cover plate was a major pain for one person. The second time, the 4-inch by 4-inch opening allowed me to simply lift the tail of the unbolted transmission above the tunnel, rotate the transmission slightly and pull the bell-housing from the car. Reverse installation was just as easy. And, there was less chance of pinching the wiring harness.

I would have designed the cars with a small removable front cover plate, and I no longer dread removing the transmission if needed.

Regards, Bill

 

[WHT]

I decided to add the first image against my better judgement this morning (flame suit on).

The new tunnel cover overlaps the small tunnel cutout by three inches. The picture shows when I was fitting the cover and the red outline shows the approximate size of the actual cutout. As mentioned when installed, the cover edges are sealed with Dow 795 Silicone and the screws are threaded into barrel nuts.

Besides aiding transmission removal and installation, the cover allows inspection and servicing of parts that are normally hidden (like the emergency brake fittings, u-joints and seat-belt bolts.

OK, I feel better now (cathartic cleansing - purification or purgation of gilt through the open admission of your crimes against mankind and nature).

Also, I placed a fitted sheet of 3/4-inch plywood on the floor of the car to aid transmission removal/installation and protect the edges of the door sill. A 2x4 was screwed to the bottom of the plywood at the door to hold the wood edge slightly above the sill; and two, thin wood pads were fastened near the sill as shown in the last picture..

The passenger door panel was removed to install a new window regulator and the dash pad was removed while fitting a hardtop.

Regards, Bill

 

[BobHaskell]

Bill,
Thanks for the additional details. I like the use of the plywood to protect the floor/sill. I've used a moving blanket, but I like this better.

 

[WHT]

Thanks, Bob.

This was the first time I had removed a Healey transmission and I was afraid of damaging the door sill and pinching the wiring harness.

Here are two additional pictures for Volker that show the rolling jack I used to support the transmission. The jack allowed the transmission to be tilted up and down, and rotated longitudinally as needed to clear the bell-housing opening ($125 at Horrible Freight and well worth the money).

Its not difficult to remove and install the transmission. But, the first time is a major learning experience (at least for me). I should add that I was removing the Healey transmission to install a Tremec T5 which has a slightly longer tail shaft . Some pictures show the Healey transmission and some show the T5. Both transmissions use the Healey bell-housing.

When sliding the transmission into the clutch assembly, it was good to support the back of the engine with a mechanical jack seen in the first image (no chance of having a hydraulic cylinder bleed pressure). The jack allowed small changes in engine height to help align the transmission shaft and ease the transmission home.

Regards, Bill

 

[Editor_Reid]

Bill,

Thanks so much for this! Your shop/garage looks exemplary, like an operating room, the Healey looks like condition Perfect+, and the photos are terrific.

One question though, did you paint the car and the lift at the same time, or color match one to the other later?

 

[WHT]

Hi Reid,

Thank you for the extremely nice comments.

My wife and I bought our Healey to drive on trips; and we are working to make it as reliable as possible so we can drive it as much as possible.

Regarding the lift paint color, it was just a coincidence. Advantage Lifts use a red paint similar to Farm And Implement paint as used by Massey Ferguson and other industrial companies. As it turns out, this color is similar to Austin-Healey Colorado Red. The Farm and Implement paint is great for painting lifts, tractors and touching up road chips on the Healey underside!

Regards, Bill

 

[BN6_2197]

Bill,

thanks for the details in particular the pictures. It makes the procedure much more clearer to me. It seems that removing the transmission in particular the first time is an intensive task, at least for me. I am an IT guy with no long track record as car mechanic :-D

Gents, thank you all for your contributions,

Volker

 

[Bob_Spidell]

When I was younger, stronger and dumber I lifted an gearbox/OD out by myself; I don't recommend it (I'm lucky I didn't get a hernia). I think the combo is about 200lbs.

 

[WHT]

Bill,

thanks for the details in particular the pictures. It makes the procedure much more clearer to me. It seems that removing the transmission in particular the first time is an intensive task, at least for me. I am an IT guy with no long track record as car mechanic :-D

Gents, thank you all for your contributions,

Volker

Hi Volker,

I hope you didn't get overload from too much information. The work can seem complex, but is not actually as hard as it sounds. Especially, if you have a friend to help. Maybe, some of the following information collected from the forum will help? I used this when pulling and replacing my gearbox the first time:

A useful link is posted immediately below this.

> Transmission Removal/Replacement <

This is a posting from bighly (might want to skip the wife part ):

bighly - I have mastered the art of pulling and reinstalling the 1960BT7 transmission alone (this take about a half day). You need to go rent a transmission jack that has the tilt adjustments. The smallest one you can get is best. I pull the car up on to ramps in front then jack stands in back. (Use common sense, although your wife could clean up on insurance when she finds you squashed after hours of silence.) She will be disappointed in your judgment and will say I told you so about dumping money into that old wreck, once again, this time over your grave). ​

Ok so let’s go:​

1>remove seats and transmission tunnel
2>disconnect battery
3>disconnect slave cylinder (tie out of the way)
4>disconnect OD electrical feed and speedometer cable (tie out of the way)
5>remove starter (keep track of connections) (caution, sparks smoke heartache, you did disconnect the battery right?)
6>place scissor or floor jack under oil pan (as Bob said, use a block of wood about the size of the pan base as padding)
7>remove driveshaft (mark it so it goes back on the same way)
8>place transmission jack under transmission (strap with chains)
9>remove the bell housing bolts and rear mounting including the thrust buffer adjuster what-ya-ma-call-it
10> careful not to stress the output shaft and clutch / pressure plate gizmos ($$$)
11> slowly jack up the transmission a tiny bit (probably should just remove all the rear transmission mounts
12>pull the transmission rearward (if it binds stop and find out why, oh ya one more bolt etc)
13>using the twisty adjustment dinks-boomps dealie on the transmission jack rotate the entire transmission to allow clearance of the bellhousing (it don't come straight back, it must be twisted, ergo adjustable transmission jack)
14> by now the transmission rear is going deeper into the driveshaft tunnel (again go slow be aware of binding, and go gentle on her)
15> once free of the clutch/ pressure plate assembly you should be able to take the fan belts you pulled off of Keoke's car last night (hehhehe) and use them to walk the transmission perpendicular to the car. (cardboard on the floor of the car will save you getting grease spots all over and will protect those worthless aluminum door trim pieces thus retaining your shine and show points)
lost count>Oh yes, then unstrap the chains from transmission
lost count+1>now place the transmission jack near the passenger door and lift the transmission on to it. Strap it back down
lost count+2>go have a cold beer or 3 because you just committed to buying some very expensive parts, and return Keoke's fan belts after dark

Hope this helps, I have done this more than once and it works fine (the transmission pull not the fan belt swipe)

This is a followup by wlivesey:

wlivesey - Well thanks everybody you gave me a lot of good advice. And I think these postings were more help than either of the 2 manuals I have. So for those of you who are interested: I was able to get the transmission out by myself, and yes I can feel it in my back...and I was looking a little grubby at work - I never could get all that grease out from under my nails...but it was all worth it. I used dog leashes instead of fan belts to handle the tranny.

And I had to take off the cowl that goes around the bell housing in order to clear the bell housing. Never used the tranny jack that Bighly suggested but I definitely think it would be worth it and I plan on using one for the installation (especially since it is expected to be more difficult). Again thanks a lot especially for those guys who took the time to provide so many details.
Now let me go find that heating pad for my back...

Finally, a few slides I made with more information:

Good luck.

Regards, Bill

 

[Bob_Spidell]

re: Step# 6. I recommend using a piece of 1x12 (or thicker) around the size of the pan, under the pan to distribute the weight. I did this once with a length of 2x4 and it made a perfect--and permanent--impression of the 2x4 on the pan,

 

[BN6_2197]

Gents,

following your advice I am progressing on the project of removing the transmission from my BN6 very well. But I got stuck while trying to disconnect the clutch slave cylinder from the bell housing. I was able to remove the lower bolt fixing the cylinder to the housing (the one marked red in the attached picture). But I am not able to access the second (upper) bolt, neither from under the car nor from above. Any advice on this is really appreciated. I don not want to open the hydraulic system and get the transmission with the cylinder still fixed on it out of the car.

Thanks,

Volker

 

[BobHaskell]

Volker, you should be able to access the upper bolt from inside the passenger compartment after removing the gearbox cover. With regards to the hydraulics, the bleeder screw and the hose are swapped. The bleed screw should be on top of the slave cylinder.

 

[Bob_Spidell]

I can't tell for sure, but that bolt head looks large to me. It should be a 3/8" fine--24TPI IIRC--bolt; maybe someone has tapped for a larger bolt? I routinely install thread inserts for these bolts as the hole is prone to cross-threading.

While you have the gearbox out, you might consider a bleeder extension. I think there's a fairly recent conversation on here about them.

 

[BN6_2197]

Volker, you should be able to access the upper bolt from inside the passenger compartment after removing the gearbox cover. With regards to the hydraulics, the bleeder screw and the hose are swapped. The bleed screw should be on top of the slave cylinder.

Bob, unfortunately I cannot access the upper bolt from inside the passenger compartment. It is underneath the sheet on which the seat reside :-(

Do you have a photo how it should look like from inside the passenger compartment?

Volker

 

[BobHaskell]

Bob, unfortunately I cannot access the upper bolt from inside the passenger compartment. It is underneath the sheet on which the seat reside :-(

Do you have a photo how it should look like from inside the passenger compartment?

Volker

Volker,
Have you removed the gearbox cover extension assembly (AHB8381 / item 5)? See the Gearbox Covers page in the Body Details section in the BN7/BT7 parts manual.

 

[BN6_2197]

Volker,
Have you removed the gearbox cover extension assembly (AHB8381 / item 5)? See the Gearbox Covers page in the Body Details section in the BN7/BT7 parts manual.

Bob, no I haven't. Is this relevant also for my BN6? Your link refers to BN7/BT7 parts.

Volker