MGB: 77MGB Shifting Oddity

Oct 30, 2009 11:17:32
Kyreb1862

The gearbox in my 77 shifts fine except when trying to shift to first from neutral at a stop. It is almost imposible to go from neutral to first at a traffic light unless you shift into second and then go to first. What would cause this? Bad synchro's. Otherwise the gearbox shifts just fine. It's been like that since I have owned it (2+ years)

Oct 30, 2009 11:21:56
Steve S

Sounds like a bad first syncro to me.

Oct 30, 2009 11:43:48
Ralph 7h

When standing still and just ideling, I would first considre to service and lube the shifter itself. You will get access by removing the gater boot and the arm rest console, remove the four bolts that hold the black oval plate on the tunnel and then the three special bolts and spring washers that hold the shifter locking ring. Take care not to loose the nylon bush at the lower end of the shifter, if it has not gone lost already.
If so, order a new one and put it on the small ball at the lower end of the shifter. After cleaning the large swivel and it's bearing graphogene greas on all trust surfaces does wonders.
It will take you 1/2 an hour to do this and may be 10$ for a new nylon bushing. Just risk it, changing the synchro on 1st. is an other theme, time consuming and expensive...so worth to try the lube service first.
BTW, I had the same 'problems on my 1975 RD and cured it the way discribed...

Oct 30, 2009 12:50:28
Filth and Greed Motors

My car does this too, and in reverse. I think it has to do with a worn-out shift linkage, but I think mine is worn inside the gearbox. If it was the syncro, it would grind. Mine just won't go into gear. I am going to a rebuilt Datsun 280zx box in about 4 weeks so that will solve that problem...

Oct 30, 2009 13:03:42
Kyreb1862

Thanks Ralph. This will be a good cheap easy fix to try first. I'll post results when I get it done.

Oct 30, 2009 16:19:46
RAY 67 TOURER

Check your clutch hydraulics first. It could be that the clutch isn't fully releasing when the pedal is pressed to the floor. This would show up in reverse and first gear. RAY

Oct 30, 2009 16:27:31
scotabbott

I vote with Ray. Difficulty shifting into gear is often a clutch release problem. A simple way to test is:

have car in neutral, idling. Try to put it into first. If it's difficult, then

shut off the motor and see if it goes into first easily. If so, it's the clutch release problem

Oct 30, 2009 18:34:00
ClayJ

If not the clutch, which I would suspect first, then:
I was having the same issue with first and reverse. My rebuilder replaced Moss part 462-115 which Moss now list as NA. This cured my problem. Seems the teeth on this gear get "flatted" at the front edge. This problem was also characterized by rarely having to rock the car to get into first or reverse.

Oct 30, 2009 20:48:31
comart45

Please keep us posted on this one.

Oct 31, 2009 06:16:19
MrMarty51

When You push in the clutch the shafts in the transmission are still turning,WhenYou try to put the transmission into gear the synchros are acting like a brake to get everything stopped.First gear synchro does`nt work as well for a brake as 2nd or third gear synchro.
If You try to put the transmission into first gear and it grinds tthen You have a problem with the synchro in that gear.
There is no synchro in reverse so it will grind the rotating shafts and gears to a halt.
If when You try to put it into reverse gear and if it keeps grinding and will not stop the shafts from turning then You may have a problem with the clutch itself or the hydraulics of the clutch system.
FWIW,I always slide the trans into 3rd gear then to reverse or first without letting up on the clutch in between..

Oct 31, 2009 07:37:38
ClayJ

John did not state it was grinding; he said he couldn't get into first/reverse.

John, when the car is in this condition does it help to hit third-gear and then select the gear?

Nov 02, 2009 09:18:43
Kyreb1862

[quote=ClayJ]
John did not state it was grinding; he said he couldn't get into first/reverse.

John, when the car is in this condition does it help to hit third-gear and then select the gear?[/quote]

The car shifts into first with no problems if you go from neutral to 2nd and then to first.

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