Gearbox part no'

[nofinchance]

Hi.I am on the brink of buying a new gearbox My car is a 1981 DHC fitted with the sprint engine and(broke)5 speed box with a matching axle.Before I buy is the box I need known as a LT77 ? .thanx all for previous advice on this I am going with a service exchange box,changing the clutch,mounting rubbers and bushes while i am at it.Thats my bank holiday full then[:p] .

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[Underdog]

Yes it is an LT77 but there are some subtle differences through the years. The very early ones up to gear box# CL22476C have a smaller input shaft and bearing. CL22477C & up got the larger/heavier brg & gear. Also, the last version, that should be in an 81, had a taller 5th gear overdrive ratio. The engine will turn less rpm for given speed. I'm not sure how you identify this last version as the parts catalogs go by the VIN# of the vehicle it is in. The numbers I'm quoting are from a TR7/8 catalog. The LT77 was also used in sedans so a replacement very well may have a different numbering system.

What is exactly wrong with your gearbox? Unless totally destroyed I would rather rebuild my original unit. I've done three of them and they are fairly easy as gearboxes go.

Jim Underwood
72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.

[Underdog]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Underdog</i>

Yes it is an LT77 but there are some subtle differences through the years. The very early ones up to gear box# CL22476C have a smaller input shaft and bearing. CL22477C & up got the larger/heavier brg & gear. Also, the last version, that should be in an 81, had a taller 5th gear overdrive ratio. The engine will turn less rpm for given speed. I'm not sure how you identify this last version as the parts catalogs go by the VIN# of the vehicle it is in. The numbers I'm quoting are from a TR7/8 catalog. The LT77 was also used in sedans so a replacement very well may have a different numbering system.

What is exactly wrong with your gearbox? Unless totally destroyed I would rather rebuild my original unit. I've done three of them and they are fairly easy as gearboxes go.

I just read your other post. Doesn't sound terminal to me. Most likely a syncro and possibly the dogs on the gear chewed off. I can see that for you the rebuilt unit may be more appealing. It would be nice if you could be assured of getting another late style box though. Too bad you are on the other side of the pond as I've developed a bit of a collection of bits for these. One thing I've learned is the 5th gear syncro is the same as the other two and they never go bad. So a 5th out of a parts box can be used saving a bunch over new.

Whatever you chose, best wishes geting it back running.

Jim Underwood
72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Jim Underwood
72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.

[nofinchance]

your tag is true underdog you may or may not be handsome but you are handy.[:)].I have been driving my car with it's faults and it will be OK sometimes and others it will not engage 4th and second is starting to go on solidarity trip getting grindy and stiff.I am going to order the rebuilt LT77 box and get my spanners out.It looks simple enough but when was anything as simple as it looked[V].Thanx all for the knowledge about this I will let you know how it goes."Im going out to the garage....I may be a while"[:X]Steph

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[Hasbeen]

Steph, it seems strange to me that your problem is intermittint.

If it were mine I'd check everything I could before pulling the box.

Is it full of oil?

Could there be a bit od gravel in the linkage, between the gear
stick, & the box itself?

Could you have a problem with the clutch master, or slave?

Worth checking, as they would be cheep fixes.

If you have to pull the thing, make adequate preperation. These
boxes are heavy.

Hasbeen

[nofinchance]

Thanx hasbeen.I like fine wine,good company and expensive gifts [:X]however cheap car repairs are welcome[:o)].The gearbox has jumped out of 4th for a while now .I looked at the oil level with crossed fingers and it's ok.My dad a retired Agicultural engineer has had a look (which was a miracle as he is always telling me how he rebuilt combine harvesters with string and spit but when my car needs work it's "ooo don't know nowt about them")Anyway he has pronounced the box terminal with weeks to live[xx(].I have looked at second hand ones and thought it out and am going to get a refurbed one.Do it once and forget it for another 30 yrs[:0]..I hope.
Then I just need to mend the lights that won't pop up,the heater fan,that bit of rust on the rear arch......etc etc.....[:(]

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