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MG TD TF 1500 - Where does one look for a 4.3 MGA rear

Starting my search now for an upgrade later. I know ebay but that is a gamble at times. What other sources are there to improve my odds of getting a known good 4.3 rear end?
l rutt

You might want to post that question over on the MGA board. For our part, we were able to get one from a member of the local club who owns a number of MGA's. Good luck to you.
Safety? Fast?
Scott Ashworth - '54 TF
S. R. Ashworth

I bought a good one on eBay a few monbths ago from a knowledgeable seller who answered all my questions, and clearly knew his onions. $250.

Tom
t lange

You might try oconnor classics online. They did my conversion and have a lot of parts. They can do the conversion for you on an exchange basis, also.

http://www.oconnorclassics.com/

regards,
Larry Ayres
L Ayres

I bought a complete 4.3 differential pumpkin from a salvage yard to get the parts I needed. My thinking was that the gears are seldom without lubrication and resist most any other abuse as long as they have not been exposed to the elements.
Jim Merz

I have a MGA rear end in my TD which I'm going to replace with a B rear end sometime in the future. Not sure the ratio but it came out of a '62 MGA MK II with a 1622 motor if that helps. Problem is that its located in California. Email me if you are interested or if you want photos.

Regards,

Tim
Tim Clark

Tim,
a 1962 Mk II MGA should have had a 4.1 rear end, why change it for a 3.9

thats only a 4.9 $ change or less than 200 RPM at over 4000 RPM,
( ie. 65 MPH becomes 68 MPH)
you won't notice it here, but you will shift down sooner in the hills

I have a 4,1 in my TF 1500 and can handle hills better than other club members later MGB's
Don Harmer

If you can’t find one on the BBS-MGA area, try Hemmings A lot of us who have MGAs have put MGB 3.9 pumpkins in our cars.
David Werblow

Also try MGVR MG vintage racers, Google vintage race cars.
Make sure you get the companion flange, the part that goes from the rear axle to the drive shaft, or propeller shaft
Len Fanelli

Just to elaberate on what Len said, besides the pinion to driveshaft flange, you'll want the pinion bearing spacer as well.
Steven Tobias

I have a 4.1 in my 51 and love it. Runs nice on the freeway, have to do a little shifting on the hills though.
Tom Maine

So a 4.1 will work ok with a std TD spec engine. This is not a MKII or anything. It's flat in florida so hills are not a problem. If a 4.1 works I'd look at that. Question is, what years of MGA would a 4.1 come from?

I understand about all the parts needed. I've downloaded the document on the upgrade and I'd be inclined to just get the whole rearend to make sure I was covered.

First gear is truly worthless in the car right now. I understand why it wasn't synchronized, no need to.
l rutt

Here's one on ebay right now:

http://cgi.ebay.com/ebaymotors/MG-MGA-4-3-Differential-MGTD-mgtf_W0QQcmdZViewItemQQhashZitem2eac1541c9QQitemZ200455569865QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Cheers

Larry
Larry Karpman

And it won't smell like cigarette smoke, just fragrant Hypoid oil.....thank goodness it comes from a smoke free environment.....sheesh!!!!
gblawson(gordon)

So, after all is said and done, is a 3.9, which I have two of, too much for a 1500 engine to run the hills like in West Virginia, Kentucky etc? PJ
Paul Jennings

That ebay diff posted by Larry looks like a winner. I would definitely go for it! The seller knows what he's talking about and is willing to send you just the parts you need for a very reasonable shipping cost. If you are running a stock TD, I would recommend the 4.3. It slows the engine down to a very comfortable level (3500 rpms at 58 mph), and still has some get-up-and go! 1st gear becomes useable and, on the flats, it feels like the same car with "overdrive". You never know where your TD will take you...you will enjoy travelling when you can keep up with traffic and can hear yourself think. If you ever make it to hillier country, the 4.3, with some aggressive shifting, will still climb acceptably.
Steven Tobias

I Rutt,
The 4.1 was stock in the 62 MGA only. It may have been an option on earlier cars. Have a good day!

John
John Progess

The 4.1 was also standard issue with the MGA TwinCam. It is indeed a good choice, and I will endorse it after having it installed in my TD.
Tom Balutis

One more time, is a 3.9 too tall for a 1500 engine? PJ
Paul Jennings

Good for a 1500 engine... you will have more flat speed, less revs and will downshift more on hills....
gblawson(gordon)

I just checked the ebay offering. It sounds like it's been dissassembled and is just a collection of parts now, not the whole center section. Will that do for my TD? I'm thinking there may be some pieces missing from what I read in the conversion article.

And the descriptions has been changed from a 4.3 to a 4.1. I'm not so worried that it's a 4.1 but am concerned that it contains all the parts needed.

If someone could view the ebay link and provide me some feedback I would greatly appreciate it.

http://cgi.ebay.com/ebaymotors/MG-MGA-4-3-Differential-MGTD-MGTF_W0QQcmdZViewItemQQhashZitem2eac1541c9QQitemZ200455569865QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories


Thanks
Larry
l rutt

The 4.1 works fine in the TD. You do find a little more shifting if going on hill climbs but the runs on the road are great. First gear actually has an use with this. Not much, but more than pulling stumps as the original. The 4.3 or 4.55 both work well to. we have many different ones in our club and they all work much better than the original 5.12 they came with.
Tom Maine

My question is though, will the parts being offered be sufficient for the swap? Apparently it really does not come with the whole center section.
l rutt

The text reads that he is willing to sell the entire assembly, or just the gears, bolts, flange and spacers. The housing is not used in the TD swap, so why buy it? Save $25.00 in shipping and get just the parts. When I put the 4.3 in my TD, I acquired an MGA center section and used just the gears and flange. I put in all new bearings and seals. I kicked the housing around the garage for a couple years and finally took it to the recycler for scrap as nobody needed or wanted it.
John Masters

I would still grab it! You need only the ringgear, pinion w/nut and washer, pinion flange (bolts to driveshaft), and don't forget the pinion bearing spacer (the tubular thing that is shown next to the tape measure).
Just for the heck of it, I would also ask for the 8 ringgear bolts, 4 nutplates, and the tapered pin (I don't see it in the photos) that locks the ring in place (ninth hole). All are spares, incase you lose or damage your's. Everything else is garbage! These gear sets are getting scarce, and hopefully you will get this one for a good number.
I've said this a hundred times...This is, in my opinion, the single most rewarding job that one can do on these cars. And the best part is that it is completely sanitary-no one can see it!
Steven Tobias

Great. I'll go for it then.

Thanks for the input.
l rutt

This thread was discussed between 19/03/2010 and 31/03/2010

MG TD TF 1500 index

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