| Author | Message | ||
     David Gore Moderator Username: david_gore Post Number: 4108 Registered: 04-2003 |
I am starting this thread to help a long-time reader (Richard Grey) of this forum who I hope will join as a member for our mutual benefit. Richard has submitted the following request through me: "Specifically, I have a question about identifying an EPW manual transmission. I recently purchased a 1953 Bentley R-type and in the extensive owners notes there is an entry that the car has a "Continental" transmission. I am wondering where the numbers are on these transmissions and what would be the designation for a Continental transmission." . | ||
| Richard Gray New User Username: mooney1el Post Number: 20 Registered: 08-2016 |
Thank you David!! Will look into the membership path. | ||
| ChristopherCarnley Unregistered guest Posted From: 109.159.63.241 |
I would have to see the notes, but it could mean one of two things. 1) The rear axle ratio has been lowered to 13:40, giving the Continental higher gearing. I mean "a lower ratio"!! 2) The gearbox gear train may have become so damaged that the only production gear train available was the R Type Continental gear train designed to cope with the higher geared 13:40 axle. What is the chassis number of the car? (Message approved by david_gore) | ||
| Richard Gray New User Username: mooney1el Post Number: 21 Registered: 08-2016 |
Thank you Christopher for chiming in, your expertise is greatly appreciated. I am trying to identify what transmission I have installed in B351SP. Let me put a bit more perspective on the conundrum. The following is an excerpt from a post I started on the US RROC Forum. I do not have any records prior to 1974 except the owner notes shown below. The history card obtained from RREC shows original transmission as BB 7868W and rear axle REL 1286 7B.702.7630. The transmission currently shifts just fine, only a little stiffer than the one in my totaled Mk VI. Since I live in the relatively flat lands of NE Florida, I have no problem starting in second gear at all and that is my normal procedure. I have attached a page from the Service Manual showing the available variants . Other than the standard ratios, there are two close ratio variants available with one labeled "Continental". In going through the extensive paperwork I received with the car, I see that sometime prior to 1974 a "Continental" transmission was installed. I do not have service paperwork showing this, only a note written by the owners who had purchase the car in 1974. How do I determine what transmission I have? Where is the identification number on the trans? Apparently the car was purchased by the Pre-Pre owners with a defective transmission since immediately thereafter, a rebuild was commissioned. Work was performed by New Bedford Dodge in North Dartmouth, Massachusetts (Horrors???). Attached are the service write ups showing parts replaced etc. Based on the part numbers, this work was concentrated primarily on 3rd gear as the synchro cone (RG4380) and sleeve (GB5374) were replaced along with part No RG4381 4th gear synchro Cone. From this time when the car had approximately 80,000 miles until 2019 when it went to a new owner, there is no record of additional trans work through the next 44 years. However, in 2019 the new owner, and the one from whom I bought the car, had to have the transmission worked on as it was popping out of 3rd and then stuck in 4th gear. Attached here is the service write up from Shamrock Motor Co, New London Connecticut, for this work too. Here they replaced part RG5471, Key 3rd/4th OS Bentley53 and 4th Gear Synchro - Used. Shamrock modified 3rd gear to accept a snap ring to retain the thrust washer. Is this a recommended modification? The car had only been driven about 250 miles since the last transmission work. After draining the fluid (Only got about 60% of the required volume out) and replacing with Redline MT90, the change has gotten considerably smoother after covering about 100 miles. I have noted that the transmission gearing is quite different than the one in my previous 1952 Bentley MK VI which was destroyed in an accident. Norm Geeson replied to my post with the statement, among others: "If this is a “Continental transmission” it would be worth quite a sum for spares, particularly the gears. I would be inclined to refit the known good standard transmission and sell the “Continental transmission”. The problem here is that the “Continental transmission” is an unknown and should it fail in a major way, individual gears could be almost impossible to source."      . | ||
| David Gore Moderator Username: david_gore Post Number: 4110 Registered: 04-2003 |
Welcome Richard and great first post covering new ground regarding the "Continental" manual gearbox. I am sure our Early Post War custodians especially Christopher Carnley will find this thread most interesting. I will be interested in discovering whether the "Continental" transmissions were fitted to vehicles destined for Australia. | ||
| David Gore Moderator Username: david_gore Post Number: 4112 Registered: 04-2003 |
Richard, Christopher Carnley has sent me the following information to post on his behalf: "The pictures are for the gearbox query, and I will add more when I have sorted the "wheat from the chaff" The washer story is in Service Bulletin BB196, found in the PW [Post War] Technical library. The casing is from a gearbox that I bought from America about 2 weeks ago, contemporary with Richard's, the casing No is RG3117, and is not the gearbox number. The close coupled (close ratio) gearbox was developed for the MK VI from 1947, and is a rare hybrid of the Standard and the Continental, I will explain in detail later. The "Continental" is not all that close ratio, it was developed to cope with the lower 13:40 ratio axle.    Regards Chris." | ||
| Richard Gray New User Username: mooney1el Post Number: 22 Registered: 08-2016 |
Thanks for posting that info. I will see if I can find any numbers at all on the case next time I crawl under there. I had read BB-196 and understood what it was about and that is one of the things that was confusing to me. It would seem that Shamrock installed a snap ring to restrict movement of the thrust washer. To me that would be a strange fix but perhaps necessary because correct parts are not readily available. | ||
| ChristopherCarnley Unregistered guest Posted From: 86.182.166.22 |
PW Post War. Moderator Advice: I have edited Christopher's earlier post accordingly  (Message approved by david_gore) | ||
| Richard Gray New User Username: mooney1el Post Number: 23 Registered: 08-2016 |
Probably not relevant, but this number is stamper on boss on the right side of the case toward the front. I will have to get a mirror to see the top of the gearbox near where Christopher's photo shows a number.  | ||
| ChristopherCarnley Unregistered guest Posted From: 86.182.152.247 |
Hi Richard, That is a machining station number. The serial numbers begin with "BBXXXX". They are on the top of the casing at the rear and the bottom rear, close to the head of the second motion(lay) shaft retaining bolt. Chris. (Message approved by david_gore) | ||
| Richard Gray New User Username: mooney1el Post Number: 24 Registered: 08-2016 |
Update - After cleaning the bottom of the transmission, I found two more stamped areas. On a rear bottom boss is a stamped W as shown in the attached picture. Also attached is a picture of the number BB5486. Just above the BB5486 number, you might see a faint M. Since the build sheet shown original transmission as BB7868W, it would seem that the transmission has been change at some point in the car's existence. So, the owner's note that pre-1975 a Continental transmission installed is at least possible. The questions remain; do I have a Continental transmission? And; is the 2019 "fix" of adding a snap ring a legitimate procedure?    | ||
| ChristopherCarnley Unregistered guest Posted From: 217.39.245.61 |
Richard, BB5486 is from a 1950/1951 MK VI car, probably a dismantled one. The "W" means the original washer type .175" thick and that is why it broke. The snap ring idea is another of the renowned "Cobbold de Tuppe" franchise, and the remedial work should have been done as shown on my third picture above. All of the Continental gearboxes are from the 7500-8500 series, and all are stamped very crudely, "CONT". (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 4113 Registered: 04-2003 |
Christopher has kindly provided the following image and comment for me to post on his behalf:  This is a picture of an R Type Continental gearbox, that I built for Padgett Motors about 3 years ago. The "M" refers to the post D series mainshaft modification. The factory "CONT" marks were all like this, and made with just a capital "C" an a small chisel. |
