OD Gearbox Experience...buyer beware...

Hello,

This last week, I procured a locale in the NW where a guy said he had several OD Gearboxes two he said were rebuilt, one that's in a car. I drove to his house, examined one of the OD gearboxes that he said were rebuilt. The guy was friendly - and answered my questions, albeit his responses were thick with lots of stories about how the gearboxes were rebuilt, replete with riddles that I began to note didn’t add up? I’d been doing research, though - I was on a rather steep learning curve. The OD Gearbox looked clean, looked good, externally. I asked to have the larger inspection cover removed, he agreed. It had all its teeth. I turned the main shaft slowing, (never seen the inside one before, lest a workshop manual b/w pictures). Looked pretty good. Didn't remove the OD inspection cover - didn't know there was one to be honest. I agreed to pay an agreed amount for the OD, contingent on an expert opinion - to confirm what the seller was saying about it being an excellent OD Gearbox. The guy agreed to a written agreement of 7-days - for a full refund, if the gearbox wasn't up to snuff. He swore it was rebuilt. We both signed it - - I used paypal for the purchase. (never use actual dollars, either check or Paypal) and always have a written agreement, no matter what.

Fast forward to about an hour after I left his home - drove to a reputable mechanic in the NW (on the way to my home)...he knew I was headed to see the gearboxes. I arrived at the very well appointed MG Shop - full of beautiful British cars and competent mechanics, hard at work. The proprietor was there to greet me. He charged me a previously agreed fee to examine the OD.

He opened then peered into the larger inspection cover on the gearbox portion. Once done - he looked at the reverse gear set. Worn in portions; rounded teeth here and there - but no broken teeth. Dodged a bullet, whew, I exclaimed! He checked the Input shaft, good he shouted! Bearings seemed good (based on the snug-factor of the shaft, output shaft felt good too he said). Gear faces overall, no nicks, pretty good shape.

Then he went through all the syncros, one by one - pushing the odd looking tooth - that's bigger than the rest on each syncro, back - looking for correct clearances. Syncro One: 70% worn, Syncro Two: 70% worn, Syncro Three: 50% worn, Syncro Four: 50% worn. The Expert loudly said....”This Gearbox has never been rebuilt with a slight sigh and then a smile? It’s got soot on the shift forks and the syncros are shiny on the edges...this dang thing’s NEVER been rebuilt!” My heart pounded, I said...not good. Yet…that was the good news. The bad news was forthcoming...he removed the inspection plate for the OD unit section and he muttered...NOT Good Dan, not good. Replete with metal shavings, the cover/filter screen was caked! He said, he'd never seen this before - and this man has seen thousands of gearboxes. I felt like a patient who'd just been pronounced with cancer. He said that the gearbox was good/bad and ugly - a hodgepodge really. Some good, some bad, some ugly? The solenoid tested fine and the internal OD pump was working as well. He said, it needed new syncros, and because of those metal shavings - the gearbox was suspect and can't be trusted. Possible bearing wear, or shims that were eaten up at some point during its long life. A 69 gearbox based on the S/N. Sure - it could work fine - or it could not work fine. In the end the money transfer via PayPal was canceled, (that evening)…thanks to the agreement. I returned the gearbox to the fellow the next day (today). The guy was agreeable and felt like a heel that the OD was misrepresented. He told me I was a man of my word, a lesson for him? Let’s hope so. Buyer beware, never buy an OD, without first having it examined or shortly thereafter, by a super-qualified MG Mechanic. I learned plenty too, thanks to this experience, the tuition paid if you will - to the expert mechanic, ($75) was well worth it! Thanks Mr. OD Gearbox Expert!

The serial number is: 22/61972/ 015639. On the Gearbox section, the date reads, 1/9/69. If you are looking around for an OD Gearbox and its purported as rebuilt - with this serial number...it's not!

Good business Dan, you dont have to be an expert to keep from getting screwed, just know one.

Good for you to have it looked at.

Dan,

Very methodical smart process to find your gearbox. Nicely done! I'm sure you'll find one up to snuff soon.

That's a real good posting and pictures. Thanks for taking the time to do that.

Dan how much did he seel the transmission for? and how much would it have cost to rebuilt. I am asking because i am in the market for one and i am trying to gather as much info as i can.

Nick,

He wanted $800 for it. It wasn't a rebuilt gearbox - just used, hence my returning it, no harm done. To do the necessary rebuild of a gearbox - gaskets, seals, syncros, input shaft tightness, bearings - can run upwards of over $500. Close examination is a must - don't rush it - no matter if you want the OD real bad (like I did). Whew, I've learned enough in the last two weeks to with help, rebuild one myself.

Note: I've learned plenty here - and there's a bit of a racket on the pricing of used gearboxes from lone individuals that think they can (operative word...think) - get top dollar for an OD. Rebuilders are in on it too (some, fortunately, not all)...so they charge top dollar for the rebuilds too. Spark up a conversation with a qualified MG Mechanic, clue him in on where a goldmine of MG's might be - and maybe he'll cut you a deal. Beware though - learn to analyze an OD yourself - read my initial post - and you too - can know what to look for. Especially the clearances on the syncros - and the OD Clutch wear (a black ring) hardly visible - but depending upon thickness, denotes level of wear/tear.

A used OD actually isn't worth more than $350 to $400, a rebuilt one is worth approximately $800 to $1000. Moss charges nearly $3000, mind you - that's way over priced.

Useful info and thanks for the pictures. Did you take any others that show the other check points? And any chance of loading them into Photobucket (or similar) for a higher resolution look?

Dan - great post - very useful advice!!

Rich

Derek,

Nope, just the images you see. Besides disassembly - what other check points are there? I watched the gearbox specialist - the entire time - and the only two covers to remove for inspection, are the two he removed. I suppose full disassembly could be done - but the seller wouldn't allow that. Apparently - those two covers will suffice with the correct set of trained eyes. I sure felt they were sufficient. However, any other details would be greatly appreciated. The specialists spent 1-hour doing the examination on the OD. It was quite enlightening. He tested the front and rear shafts for proper tolerances (tightness) - the bearing wear is tested there. He looked quite closely at the teeth, syncros - and checked the clearance of the syncros several times each - telling me and showing me what proper clearance is, and isn't, and tons of other stuff too.

Thanks, Dan

http://www.octarine-services.co.uk/#trans

Chris Betson in the UK, very good guy. He will sell you a kit to convert your tranny to OD. You can check out the instructions right there on his site.

Thanks for the link...though - I believe I'm going to stick with a source, whether it be a shop or an individual - here in the states...unless a scream'n deal from the UK comes my way.

Right now, there are no screamin' deals from the UK - the exchange rate stinks!

Perhaps your best bet is to find an inexpensive (?) O/D box and rebuild it yourself. Did the guy offer to come down in price when you informed him it was not a rebuild?

Yes, he did - and this story isn't over quite yet. I may be heading back to his locale, this time with the OD gearbox expert at my side to do a full diagnostic, prior to any financial commitment I make to him. The cost factor will be substantially less, this I know, for any of this guys OD Gearboxes.

The kit from the UK comes out $1200 cnd. that is expensive considering you have to use your own transmission. I found one in BC. for $850.00 problem is i cant inspect it from Montreal.

The kit comes with an OD of the right year for your car and is fully rebuilt and tested by the original manufacturer's successor.

It also has the necessary wiring loom included - is that really so expensive if you have to pay $850 for an unknown and untested unit?

As for Dan's original posting - he emailed me following Ken's link and this is my reply -

"I doubt that your OD "expert" has opened that many MGB boxes in his life if he hasn't seen chewn up input bearing shims before!

It is pretty common for the shims to break up and the bits to be mashed by the input shaft bearing and end up in the OD filter.

Also you can tell bugger all about the condition of a box unless you do a full strip down.

It is very rare for the synchro rings to wear to the point that they need replacing and provided that there is at least 1/16 inch of clearance between the ring and the gear then it is serviceable.

Main wear points are the tip of the mainshaft, the layshaft and the associated needle roller bearings. The reverse gear idler and teeth on the laygear do take some abuse and are often chipped and worn, apart from making reverse gear selection difficult even that wear is no cause for concern unless you drive large distances in reverse!

I can supply all parts for the gearbox and the OD units - but many are not available new and we have to use good used items. In particular, the supply of different thickness thrust washers is extremely limited and excess laygear endfloat has to be addressed by other means. "

Additionally - in respect of Dan's post about the OD clutch lining - the wear is NOT measured by the thickness of the material but by the axial travel of the clutch unit - during rebuild by the original manufacturer, the linings are riveted & bonded to the steel carrier and then machined in situ to give the correct travel of 60 thou.

I am sorry to say that your "expert" may have been spinning you a yarn or two!

Oh - and finally, if yours is a 79 car then the OD unit with the black label is wrong - you need the one with the blue label unless you want your speedo reading wrong by 28%!

My advice? Buy a box as cheap as possible and then go to one of John Twist's rebuild seminars and rebuild it yourself!

Chris

mgb73 Wrote:

Yo - Mr. Spanner!

Your Boldness is noteworthy! Good, learn'n aplenty old-boy - thanks and keep up the good work. I'll profit from your bits and pieces, insights and technical array of thoughts, experiences and expertise you've had. Fill up me boot and I'll drive home with a bounty of goodies, only not too much, I like my B to run well and not bottom out on the speed bumps!

Dan

Question: To Chris!!!?

Since my B's a late model - and the label needs to be blue on the OD, will my current non-OD Speedometer work and show correct speed - with an OD Gearbox of the blue-label variety??? Or will the speedometer need to be recalibrated or a 'correct' speedometer need to be inserted in the dash with the corresponding longer speedo cable?

Thanks, Dan

Your car should have a 1000 turn per mile (tpm) speedo - look on the face of the speedo and you will see some numbers, one of which should be 1000 (I don't know if any late US cars were fitted differently).

The blue label OD unit delivers 1000 tpm - the black one delivers 1280 tpm.

Chris

Hey - welcome Mr. Betson!

I have rebuilt two O/D units using your instructions - and both work great! On one of my trips "home" I'm going to have to visit your shop - I feel I owe you a pint!

Thanks Chris,

I have plenty to remember here - I will make a list. And eventually - I will know which gearbox to purchase, from a reputable source. I will pass on buying one from the UK, the exchange rate is too high.

Thanks, Dan