MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Rebuild gearbox or 5-speed?

Just picked up the TD at Neil's after having the brakes re-done (actually stops, now!)and some wiring sorted out for the horns. Made it home just in time as it was getting dark and the headlights were out! Seems that an important wire worked its way loose whilst the horn was being re-wired...so, I fixed meself.

One troubling thing, though, Neil is cautious about the gearbox as it makes a lot of "whining"(?) noise in first, and second gears. He wasn't crazy about reverse either and thinks I should have the gearbox worked on. The other alternative is to use a 5-speed gearbox. I have the 4.3 rear end and would be happy enough with a rebuild but would the 5-speed be worth the large sum of money?

My thinning wallet thinks not... but....

Best regards,

DaveL
dave lackey

With the 4.30 gears, I still reach for 'another'...however, am still comfortable cruising at 60.... Have thought about the 5 speed, but would hate to remove the stock one (even if I keep it and say it goes with the car). A rebuild isn't going to take the full amount of a new 5spd kit!
1st and rev go together, so if one is bad, the odds are pretty good the other is as well....
My 1st/rev is noisy...no jumping out of gears, but probably should be rebuilt. (my thinning wallet also determines what repairs are made)
gblawson - TD#27667

Dave,
Rebuild the gearbox, use Neil or Bob Wagner, you will be delighted with the result. The additional 4th won't be of much use with a 4.3, a waste of money, rebuild is much cheaper.

Send in your application for the SEMGTR. We are waiting to get it!
Don Harmer

Arrgghhh!
Don,
thanks for the reminder! I was going to do it last night but spent a coupla hours under the dash!!!

Will make a note to get the application out this week!!!

Best regards,


DaveL
dave lackey

Dave - First gear (and reverse) are square cut and normally whine a lot. As long as theyr are not jumping out of gear or clunking, they are probably not in bad shape. I would be more concerned about second gear whining. Our TD still has the original 5.125 rear end and we drive it all over the place, including two 5000+ mile trips through the western US. The high rpm are harder on your nerves than they are on the engine. Mine would be another vote to stay with the original gearbox. Cheers - Dave
David DuBois

I've been cotemplating a five speed also. I've got the 5.125 rear end but still need to go up our very steep hills in second so a conversion worries me. My transmission makes a knocking noise in all gearswith rapid acceration but is otherwise fine. Is this likely to be a transmission bearing to could it be the front U-joint?
Russ Oakley

Hi Dave,

I agree with all the boys above,stick with the orignal box and just get it restored if and when you need to.
Cheers

Rob. Grantham
Rob Grantham

Dave,
There have been a lot of people who had noisy and hard to shift gearboxes (I'm one of them) who switched their gearbox oil to RedLine MT90 and noticed much less noise and easier shifts. It won't make a silk purse out of a pig's ear, but my results convinced me that a rebuild is a long way off. I was worried that the tranny needed rebuilding, but after the fluid change I've had a complete change of mind.
Gene
Gene Burgess

I'm for the original g/b rebuild too, but for purly economic reasons.

A proper gearbox rebuild will cost you $700 to $800, including "take-out, put back", but not including a new 1st motion shaft ($820) or a cluster gear ($1,140). If you need this in addition to the gearbox rebuild, you might as well spring for the Hi-Gear 5-speed jobbie.

My only reservation with this, is the 10 cms that one has to advance the engine, in order for the Sierra Type 9 to fit.

Gord Clark
Rockburn, Qué
Gordon A. Clark

My gear box rebuild cost me about $600, but in my case the cluster gear and synchros and selectors were fine. I did get a new layshaft, and all new bearings. It was a lot of fun, even though I did it three times because of a wrong bearing supplied by Moss.

Some pics:

http://www.travelaire.photosite.com/MGTDRebuild/tranny/

warmly,
dave
Dave Braun

Oh, I should add, to me the charactoristics of the gear box and how it shifts is integral to the feel and heritage of the car. I did change to a 4.3:1 rear end, and I struggled with that, but to me, keeping a car's engine and gear box original is important. Otherwise, what's the point of preserving one of these cars? That said I don't have a problem with safety or serious availablity issues (radial tires or the steering box revisions some do to TCs, but I think the charm of these cars is hugely dependent on keeping them the way Abingdon intended.

As usual, I'll defend any owner's right to do to his car what he wants. But you did ask.

warmly,
dave
Dave Braun

I'll defend any owner's right to do to his car what he wants....
It took me quite a while to get used to the 4.3 gear change ....the 5 speed I don't think I will ever do. IMHO i think I would only do the 5 speed if I had a car I was going to change engine as well in.
Cheers,
David 55 TF1500 #7427
David Sheward

Could just be bad bearings. If the gears are ok, shouldn't be too expensive. David DuBois is correct that first and reverse are always noisy with the straight cut gears. Make sure you have oil in it. George
George Butz

Great comments from all and I really appreciate it.

Redline MT90 sounds like the thing I should do before our Great Adventure trip. But,now I am confused because Moss does not sell a product called MT90 but it is a 75W90 gear lube. The Redline homepage only lists MT90. Are these products the same thing?

Octagonally,

DaveL
dave lackey

Not sure about the Moss product, but if you go back to the Redline site and use store locater, you will find somewhere close to buy MT90 cheaper.
gblawson - TD#27667

Not wanting to venture into the gearbox without a proper guide (remember, this was before I found this BBS), and wanting even less to find myself laying on my back in some muddy paddock pulling the gearbox during a hectic race weekend, when it came time to do the gearbox in my vintage racer, I took two vacation days in February several years ago and attended John Twist's T series gearbox rebuild clinic in Grand Rapids, MI. It was a fantastic experience; you pay for the clinic, bring your own gearbox and tools, and John and his guys lead you thru a rebuild of your own gearbox. You do also pay for any parts needed...there is a "standard" kit of wear parts that get replaced no metter what, but they also check cluster gear, first motion shaft etc and replaced as required.

Not only do you learn how to do it from an experienced perspective, but of course you come away with a much better understanding of how it works, and what problems can crop up. I highly recommend it. The second time I took the clinic, to do my race spare transmission, there were two fellows from Texas, and a guy from Hawaii, who brought his MGA transmission on the plane, in a gymbag!

I now have done two more that I picked up along the way, and believe me, I feel a whole lot more comfortable doing almost any job on my cars.

JB
Jeff Brown

Just to be the fly in the ointment...I put in a 5 speed and cannot for the life of me understand why I didn't do it sooner! 4.3 gears are fine but you loose much too much power on hills and cruising with the old box is non-existant unless you want to go 45-50 MPH all the time, the revs are much too high for modern driving. 3000rpm for 50, 3500 rpm for 60 and 4000rpm for 70 (yes, an XPAG will cruise at 70!). While I try not to take the TD on Interstates (not fun looking at an 18 wheeler's tires go by your face!)I can if need be, and can easily keep up with traffic. Even the back roads here in Idaho are 65mph, which isn't a problem with a 5 speed, with the old box I'd be deaf cruising for 3 hours at 65!!!
Robert Dougherty

Robert,
Sounds interesting but was wondering how the first four gears are for hills and such. Seems like the 4.3 loses a bit but with the new tranny, maybe downshifts are no problem??
dave lackey

Dave,
If all you are worried about is a little noise, try the Redline transmission fluid from Moss. After 6 months, my first/reverse gears are much quieter. What I would call the bearing noise is gone. I also made a magnetic drain plug at the same time. I just changed the fluid and found it quite dirty, so I think the Redline oil cleans out the bearings, etc. A fair amount of particles on the plug. Much easier to shift when cold also.

I am not sure how familiar your mechanic is with old english cars, but even Healeys had fairly noisy first/reverse gears. I think it is the same gear for both.

Unless it is extremely bad (sounds like it is going to blow up) I would drive it until an actual problem occurs. I presume it shifts ok ?

regards,
Larry
Larry Ayres

Hi, Larry!
Transmission shifts fine with an occasional second gear jumping out but that may be my fault???

Anyways, I will pick up the MT90 tomorrow and change it this weekend.

BTW, how do you go about making a magnetic drain plug? Had one on my BMW and it really made a difference.

Octagonally yours,

DaveL
dave lackey

The drain plug idea isn't mine, by the way. Carl Cedarstrand who wrote the book that Moss sells about the differential conversion was at the GOF in Buellton last year and he brought one in and recommended it.

I measured the inside of the drain plug and found a circular magnet with a hole in the center that would fit inside of the plug. It was an Eclipse brand and I got it from some big supply house that Carl recommended in Irvine. The hole the center was big enough for a small machine screw. Magnets are very hard metal, you probably don't want to drill the hole afterwards.

I tapped the magnet and then drilled a hole of the same size through the plug from the inside out and tapped the hole. (I bought a new plug from Moss so I could
drive the car, while making this.) When all of this fit together, the machine screw going through the plug and into the magnet holding it firm, I epoxied the magnet to the plug and reinserted the bolt to hold it. The plug had a tapered bottom, so I filled the taper with epoxy. It has never leaked, and really works. I think it is the combination of the redline oil loosening the particles, and the magnet together that quieted things down.

The oil and the plug are a very inexpensive way to improve the transmission, in my opinion.

The popping out of gear problem has a specific cause. I think it is the selector forks or springs, all of which can be fixed without taking the tranny out of the car. I think however you have to be skilled, as springs go flying when you remove the cover.

Hope this helps.
Larry
Larry Ayres

If interested, Lee Valley Tools sells 'earth magnets' with holes in them... not anything much stronger then those...come in different sizes.
gblawson - TD#27667

If your TD's XPAG engine is in good tune, you don't have trouble with the 4.3 on hills. Well over 60 of our members have converted to 4.3. AND we did the "Tail of the Dragon"on tour with no problems. Yes we did downshift if below 2500 RPM, but you would do that on a 5-speed.
I have a TF 1500, with a 4.1 rear end, in super tune, and did much in 3rd, with only 2nd when the guy in front slowed too much so my rpm's dropped too low.
Dave you won't have any troubles in North Georgia or in the Carolina's with your 4.3 rear end if your engine is correctly tuned!
Don Harmer

Something that hasn't been mentioned above (unless I missed it) is that the 5-speed is fully sychro'd. No more stopping to downshift into first...that alone was worth the price of admission to me.

Other than that there's no real difference in the feel of the car in 1st thru 4th since the gear ratios are very close to those in the original transmission. 5th is for cruising - and not much use for other than that.

Gene
Gene Gillam

I found with the 5.125 stock gears that i never used first.... tons of pulling power with 2nd... I now (with the 4.30) can get up to a decent speed before going to 2nd. I think the 5 speed would still need a higher rear end to really utilize 1st and 2nd?
gblawson - TD#27667

There'd have to be a trade-off. A 4:3 may be too high for 5th gear. I have a TC and could try a 4:55 (not sure if that's available in the TD/TF differentials) but right now I'm happy with the entire range.
Gene Gillam

I agree with Gord (Lawson)'s earlier comment about the 4.3 diff - my TD has a 4.3 diff, and I used to wish I had gone higher, 4.1 or possibly 3.9 (but this may have been over the top). I now have the 5 speed gearbox, and the fifth gear of 1:0.82 gives an overall ratio of 3.53:1. This is probably too high for 1250cc or even 1466cc to pull, as Gene has suggested. A diff of 4.875 would be better, as this gives an overall fifth gear of 4:1, which 1250cc or 1466cc could probably cope with.
Roger Wilson
PS, My own car copes with a 4.3 diff and a 5 speed gearbox as it now has an MGB engine.
Roger Wilson

Is there a place locally to buy the Redline MT 50?
I'm gonna change the fluid in my TD this weekend. I live in Woodstock. Also... my first engine start is scheduled for this weekend. It's been over thirty years since Maggie has fired a lick. I'm using the spark plugs that were in her... they still say "Made in England" on the Champions. (I can't find my 3/16" Whitworth wrench... I hope I didn't leave it in the Sump)
Thanks
Sid Orr
Sid Orr

Is MT90 also better in the differential? I have a 4.3 ratio. I am about ready for changing all the lubricants. This would be the ideal time to change, if it is the right stuff.
John Masters

I use it in both the gear box and rear end... the lub chart calls for the same 90 weight gear oil in both, so the MT50 works.
gblawson - TD#27667

I opted for the Skyhook 5 speed conversion ( first class and nothing that can't be changed back) . I didn't drive the car before the change so I can't comment on the differences. I did own three Sprites with the non syncro 1st gear and can confirm that it is much quieter and can easily cruise at highway speed.

LaVerne
LED DOWNEY

Sid,

Try Atlanta Imported Auto Parts in Decatur.
404-299-5775 and www.atlantaimported.com
Don Harmer

Sid,
I picked up my Redline MT90 at Summit Racing in McDonough last Saturday. They carry a complete line of Redline products.

Cheers,

DaveL
dave lackey

This thread was discussed between 26/09/2006 and 03/10/2006

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.