[Nobbc] Mark's gearbox

[Ron Engelhardt]

Possibly the previous owner used gear oil instead of the correct motor 
oil. I would drain it and refill with the same oil you use for the 
engine 20w-50. Many people use Redline MTF although I've never tried it 
and probably never will since the motor oil works just fine. You 
shouldn't be getting resistance as you described while shifting...maybe 
your clutch is not releasing correctly???

Ron
58 MGA

Mark Darley wrote:

> I am finding that the hotter the car and gearbox get, the less  
> resistance I get on the shift.  It starts out feeling like I am  pushing 
> it through treacle from 2nd to 3rd on a cold morning, and is  fine after 
> 30 minutes of driving.
> 
> Could this be as simple as old grunge in the gearbox (It sat for 4  
> years & I have changed it out but not used any flushing fluids), or  
> just thick cold oil?
> 
> Should I use some sort of flush other than fresh oil?
> 
> Has anyone put a lighter oil in the MGA transmission with success?   
> Should I?
> 
> Thanks
> Mark
> 
> Mark Darley
> markdarley at mac.com
> Mobile Phone 415 310 5252
> 
> 
> 
> On Mar 9, 2010, at 5:40 PM, andy preston wrote:
> 
>> Mark, I started a new thread because your gearbox was getting lost  in 
>> the
>> tech session one.  I agree with Greg that if your gearbox has done  
>> 50,000
>> miles it's just tired, but is probably ok for many more miles  before 
>> needing
>> a tear down.  I like the idea of changing the oil, that might help  a 
>> bit.
>> The syncros are probably worn which is why changing up or down is  fairly
>> stiff.  Double de-clutching will help going both up and down the  
>> box.  I'd
>> try and avoid the 3rd. to 2nd., as much as possible.  Unfortunately  
>> there's
>> no magic silver bullet here; the only way to fix it is with a complete
>> rebuild or another gearbox.  I've done a couple of MGB boxes before  
>> and if
>> and when you decide to do it will be pleased to help you.  In the  
>> meantime
>> I'd be more than happy to test drive your car and you can drive my  
>> early MGB
>> which has the same gearbox except for the rear extension.  I've  
>> rebuilt the
>> box on the B so you can also see how a new box feels.  You can also  
>> drive
>> the Coupe but that has a Ford Sierra 5 speed which is completely  
>> different,
>> and that has a notchy first to second change.
>>
>>
>>
>>
>>
>> Andy
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> 
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