1973 MK II Transmission Reverse Information

[theunstated]

Hello everyone,
I just purchased my second old school Corona Mark II this one has a few engine problems but seem to be a pretty solid car other than that. The Chassis Code is MX20 and it is labeled as a Corona Mark II L. It has either a 2M or a 4M engine inline six cylinder. The engine problems are pretty simple fixes but it has an automatic 3 Speed transmission that when placed in reverse will not engage. When the car is placed into reverse there is no movement. There are no strange noises or anything coming from the transmission. All the other gears seem to be ok. I believe the transmission code is A30 but that is just from online research. I am looking for any information on the transmission and what can be done to fix the reverse problem or what transmissions are compatible swaps for the car. If anyone know what parts will be needed to fix the problem or where a good source for old transmissions are I would greatly appreciate any help. Please keep in mind I am located in Tokyo Japan. I have tried to source a replacement transmission here but haven't had any luck. Thanks in advance for any help.

Best Regards,
Aaron

[river]

Hi,

The A30 was also used in the Celica, so you could try and see if you can find one from an old Celica, but I think that wreckers in Japan may be a rare item.

I have a repair manual which describes the A30 and when I get a chance I'll have a look and see if it describes your symptons and what they recommend to fix it.

seeyuzz
river

[wilbo666]

First thing to check is oil level.

Check the oil level with the engine running, in N or P with the oil at operating temp.



Cheers
Wilbo

[theunstated]

Thanks for the replies. I appreciate the help River. I have already checked the transmission fluid at both running and not running. Fluid levels seem to be fine. Thanks Wilbo666

Regards
Aaron

[cambelt]

Very common problem with the A30,s behind 6,s . Something cracks inside the auto which lets the fluid bypass that clutch or simmiler. If it wasnt for this common problem i wouldnt own my best Mark II . They had the 70000klm old car sold but the auto shat reverse , They couldnt get another box so i bought it .
Its not a age or klm thing they just break when they feel like .
Throw that auto and put a A40 ( or D) in it if you want to stay auto.
Dave

[river]

Hi,

The rear clutch or band has failed. This stops reverse from working.

So, you can try and get an A30 from an old Celica or Carina... or another Mk II. Not sure if the Crown had the same box, circa 1973.

As mentioned, try and get an A40. This was in the RA23/28/35 Celicas, mid-late 70's Coronas and Carinas.

Or see if it can be repaired. Surely there are gearbox repairers in Japan. The A30 (and subsequent A40, A40D and A43D) are all very similar and used for many years, so I'm sure there wold be parts for them about.

seeyuzz
river

[theunstated]

Thanks River
I have been looking and now I am unsure which transmission I have. I am not sure if it is an A30 or an A40. Can someone identify this transmission. Thanks




Regards
Aaron

[river]

Hi,

Good question. I never thought about the differences between the A30 and A40 from a visual perspective.

Maybe my EPC shows something. I'll have a look.

In the meantime you can take a pic of the build/id plate and post it in this thread. Assuming the car has not been modified that will tell you the engine, gearbox, diff, and internal/external trim and colour codes.

seeyuzz
river

[river]

Hi,

Okay.. I checked my EPC for the A40 and it's not one of them. Maybe it's an A30. I need to find my EPC with the A30 in it.

The A40 has a more rectangular pan underneath, whereas yours is more square.

seeyuzz
river

[cambelt]

A30 100%
Dave

[joecoolmk2]

whichever it is, they will both fit straight in. you can also fit an A43D(overdrive) from later models but it is 80mm longer and requires tailshaft mods and xmember mods.

p.s. there should be a sticker on top of the box which has the model number on it. google it and that will tel you what gbox it is.

[theunstated]

Here is a little update. Sorry for such a long wait for the reply. I have been pretty busy with work and everything for the last few weeks. I cracked open the transmission after purchasing the rear band and master overhaul kit. Finished tearing it apart today only to find out that the Rear servo assembly has a pretty serious crack all the way through the outer wall and that what I assume is the planetary shaft housing has been rubbed on the bad break band so bad it has grooved the housing. I am open to suggestions at this point. I am in need of a transmission or the parts to fix this transmission. Let me know. I am in Tokyo as well so if you have any contacts over here that may be able to help it would be greatly appreciated. Regards.

Aaron

[cambelt]

I can help you with the parts but unfortunatly not straight away , I would have to strip an auto for it . I knew something cracks, they all seem to do it , my trans bloke 15 years ago used to buy dead trans from me for this part.
Dave

[theunstated]

Thanks Cambelt,
I appreciate any help that you can give. If you can get the parts let me know. Please keep in mind that I am located in Japan. I will pay for shipping. Just let me know. I will try to post some pictures so you can see what I am talking about. Regards

Aaron

[theunstated]

Here are the pictures of the parts that are bad. If anyone knows where I can order them or have any a transmission laying around that they may be willing to strip for these parts let me know. One picture is of the rear band. I already have a replacement for that one. Let me know what you guys think I should do. Regards

Aaron


Planetary shaft


Planetary Shaft overall


This is the part that caused all of the problems. As stated before I have a replacement for this already but it did all the damage to the above part.


I couldn't get a picture of the crack but this is the part that is cracked it is the rear servo