MG MGB and MGB GT Tech Talk
Hi,
I find shifting from 1st to 2nd a bit hard specialy when the car is "cold' after normal warm up, gets a litle better when hot. It goes in ok on quick shifts or double clutching. Is my 1st/2nd syncro on its way out ? can I replace it thru the side cover?
Thanks,
Barry S
Barry,
Cannot service the tranny without pulling it.
Is your oil level good? changed in recent memory?
How is the shifting without the engine running. Want to rule out clutch master and slave cylinder. Those items are relatively easy repairs.
Its also possible that the throw-out bearing and/or lever are worn. (tranny out for that fix also)
Clay, thanks for the reply.
Castrol 20w50 in the box 6 months old, MC fine no leaks, slave ok, shifts fine with engine off. all other gears ok, I shift very early in to 2nd and all is well. Is there anything to add to oil to improve shift ?
Regards,
Barry
You might try changing to Redline MT-90 synthetic gear lube. It gives a smoother shift than the 20-50 Castrol. Works great in an OD box too.
I'm with Dan.
But I think I'd back it down to MTL, a little bit lighter but just as tough. That's what I'm using in my Datsun box and it is as smooth as a politician's hand reaching into your wallet.
There is some question as to whether the additives in conventional gear oil are harmful to the alloys used in some of the parts in the transmission. That may just be an urban myth. But soon after I changed to gear oil, my synchros went - coincidence? Who knows. I'm sticking to engine oil.
One thing that may be of interest is that the factory manual specifies different engine oils (in the transmission) for different temperatures. 20w-50 might be a bit thick for spring and fall in Canada - although I see you've been having some great temperatures right now (unlike Calgary).
I've gone to 5w-50 synthetic engine oil since I think that covers the whole temperature range. Seems to work well.
My transmission has always been a little bit stiffer for the first shift or two after it has been sitting cold. After that it is fine. I think you have to use your judgement. If the condition is only for a couple of shifts until things warm up, and it doesn't seem to get any worse then that is probably just a characteristic of the beast. If it is more than just a little stiff and/or it is getting worse then you will have to rebuild it.
Barry, you say that the hydraulics are in good shape but have you checked for wear in the working surfaces of the clevis pins and forks at both the master and slave cylinders? There have been several threads here lately concerning same and any little bit of slop in either joint will result in less than optimum movement of the release mechanism. When that is the condition there is always just a little constant drag on the shaft and gear system in the transmission when the clutch pedal is depressed and the baulk ring function has to overcome that before a gear change is accomplished. If the rings are being overwhelmed to some degree or another that could result in more effort to get the gears to slide together.
Jack
Thanks for all the advice, I think the gearbox will come out next winter.
I would like to get some feed back about the type of lubricant others use in there boxes, so far 5w-50, MT-90, MTL.
Most MG shops specify 20w-50.
Regrds,
Barry
Barry:
One other thing to have a look at is the condition of the shifter lever ball. I had a similar "hard shifting" problem about a year ago. I removed the shift lever and found the ball was dry, and gummed up with dust/dirt and such. I cleaned the shifter ball and lubed lightly with grease, also one of the spring washers was missing--made all the difference in the world when it went back together.
Best,
Pete
Pete,
Very good point, I also found the same with my lever, I applied grease from the top without removal, it did improved a bit. I'm going to remove it completly now and do it right.
Regards,
Barry
