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1275 gearbox questions

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SilentUnicorn

SilentUnicorn

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Hi all, getting ready to help My Neighbor(elvis) do the tranny on his 74 midget. We have the replacement on the floor and getting it cleaned up and such. Peeked inside and all looks well. however the inside of the bellhousing was crud and oil sprayed. What kind of seal is used there? i looked on the moss site here and i dont see any seal listed other than the gasket. Also there are two switches on the shift assembly, reverse lamps and......? Plan on doing the rear oil seal as well any tips or tricks that might be helpful for removing the old one?


Thanx
mark

ps: we need a greasy mechanic icon....lol
 
No front seal was ever used on a ribcase tranny.
It is sort of like the engine rear "wannabe" seal.
It works in theory, not in the real workd /ubbthreads/images/graemlins/wink.gif
The input shaft should be snug in the tranny, a new clutch pilot bushing helps too.
An after market rear engine seal helps as most of the crud in the bellhousing was from the engine rear wannabe seal in the first place.

Re-reading your post, "any tips on removing the old seal"
If you find one there, do NOT remove it!, they never had a rear seal and somebody put an aftermarket seal kit on the engine. Now you need to know who's seal kit if you are replacing it. If you can't see a seal bolted on the back of the engine, there isn't one. It has the "wannabe" factory
theoretic seal which works fine for almost a whole month if properly driven off the show room floor.
Positive crankcase ventilation in a fact on most 1275 engines to keep the oil from blowing out of the rear "wannabe" seal. The rear of the crankshaft is *sealed* with a reverse spiral cut metal cap, in theory it throws the oil back into the engine. And it works great, just never rev it above an idle.

As for the other tranny switch, it is for the seat belt warning lamp cirrca 63/74

Frank
 
Frank, I took Marks comment to mean that he was replacing the rear seal on the tranny.
A front seal can be installed in the cover plate at the front of the trans, but requires machining to accept the new seal. I put one on one of my cars, and it has remained leak free, (at least there) for about 7 years.
Jeff
 
Hello Silent Unicorn,
does the gearbox have an overdrive?, as that second switch is usually the inhibitor switch that only allows selection in third and fourth gear.

Alec
 
thanx for the info, it is a non od gearbox. i havent taken a good look at the donor engine yet to see if the crud in the bell housing came from the rear engine seal. will do that today. but ihave already pulled the clutch cover and all was dry there, i will take a look behind the flywheel. If it was leaking from the front cover plate on the tranny , what would cause this? overfilling of the tranny?

How about the rear seal on the tranny , anyone ever done one of those? looking for tips and tricks....


mark
 
I actually have mentioned this before, and I know it's a bit off topic, but I have leaking issues with my 1500 gearbox. For some reason or other, despite having a spitfire gearbox with a front transmission seal and using Redline Synthetic (which really does seem to help shifts) I still have leaking problems. Drops seem to collect on the transmission drain plug, but it doesn't seem to be leaking from there (I really cranked it tight). There's also a bit of oil coming out of the drain hole in the bellhousing, which would seem to indicate that front seal isn't doing its job. Any suggestions? I lose quite a bit of oil, perhaps 1 qt every 1000 miles ... I don't really mind that much, but it'd be better if it didn't leak ... after all ... the rest of the car doesn't leak at all!

Matt
 
Mark, I take a die grinder with a thin cutoff wheel, and carefully cut a groove in the seal housing. Try not to break through. Then a sharp rap with a chisel will separate the housing for easy removal. After installing the new one, just stake it in a couple of places using a blunt chisel.
Jeff
 
Thanx Jeff, bout what i kinda figured. Sounds like a good job for Elvis and his dremel.

Matt, not sure what to tell you, is the top of the gearbox wet? if so it may be blowing out the vent, and running down the sides, if the spit box even has a vent. something else i just rememberd, from my 1500 gearbox is that where the bellhousing bolts to the gearbox, i recall that the bottom most bolt is drilled thru, and there should be a copper sealing washer in this location. Hope this helps

mark
 
That one bellhousing/gearbox bolt could be it ... I don't know if it's wet on top of the trans. I know you suggested earlier that it could be blowing out of the breather. I think that may be a possibility because it doesn't seem to leak much when it isn't being run in a while. When I drive it consistently it leaks more. Hard to say. A tolerable problem, I suppose. Hardly gearbox-threatening as long as I check it now and again.
 
Matt:

There's a vent on the top of the trans that gets clogged pretty easily. It's in the sheet metal cover on the top and looks sort of like a "mini hood-scoop".
Also, be sure that you are running the proper oil. The 1500 trans uses 90W gear oil while the 1275 uses motor oil.
For the record, my stock 1500 trans has never noticably leaked when racing or when street-driven.
 
Interesting. Are you aware of whether yours is a sealed or non-sealed version? Mine is sealed (fairly rare, I understand). I haven't checked to see if the breather is clogged, but that is a good idea. I currently run redline synthetic, which makes the shifting considerably smoother than when I ran hypoid gear oil (something like 75w90). However, that didn't stop the leaking.
 
Are you aware of whether yours is a sealed or non-sealed version?

Not sure. I've never looked. I'm not even sure if it's the original '78 trans (my engine is from a '77 1500 Spitty).
A few years ago, when I had the trans out, I removed the top cover, hung it upside down and cleaned it out with my pressure washer (to get all the gunk out of it). Then I dried it off and buttoned it up. That's the only "maintenance" I've done to it.
You're right...Red Line works great.
 
I did have a rebuilt transmission, so the box was pretty clean, but I still have to try the breather. I was also thinking of replacing it with a pipe to a catch tank, if there is indeed oil blowing out of the breather. Then perhaps I can catch it, so it'll fall back in when everything settles down. Hopefully that'll solve my problem, but before I worry about that, I have plenty of other race-prep items to do.

Matt
 
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