Recon gearbox

[Andy K]

A bit of wisdom please.......

 

I have just fitted a recon gearbox. It is quite notchy, which may not be surprising since it is "new", but I am having problems getting first and third about half the time.

This doesn't seem related to whether the clutch is in or out (at rest!), and I know it is disengaging adequately for the change since second and top are fine.

Is there any link between the reluctance of first and third gear to engage

Is this down to the selector forks or something in the box itself?

 

Any thoughts very welcome

 

Andy K

[jdbinnington]

i'm not a gearbox expert, but if it's 1st and 3rd might it be related to the shift lever acting on the change rods, rather than in the gbox itself?

 

j

[Richard Crawley]

Andy

The 6 box is fairly notchy unit anyway but all gears should feel the same. First thing is to check the remote gear selector mechanism as suggested although it's usual to check this & set it up when reconditioning the box, did they not do this?

[marvmul]

Perhaps 1st and 3th gear being notchy doesn't mean that much, it does not exclude for sure that the clutch can't be wrong.

[Bill Wirz]

Andy,

Could be that the detent spings are new (have more tension). They are located in the top cover. This is not bad for the transmission and might get better with break-in.

 

Bill

[Andy K]

Thank you for your thoughts. In the meantime, a problem has reappeared with the newly assembled units which had previously appeared when the old box was in, namely a jerky clutch release which appeared after the box etc got hot. This was resolved last time by removing the box,cleaning up the nose sleeve surface and refitting the box.

So the box has come out again, nose sleeve all shiny and very lightly greased and the lot put back as recommended ( bellhousing settled in square, two big bolts first and then the rest evenly). Tomorrow night I'll put a seat in and take it for a run to see if all is well. If not, top cover review next. A friend with a garage knows the folk who rebuild these units for the local retailer here and has offered to get help if there is still a problem.

I'll let you know how we get on! Thanks once again to you all.

 

Andy K

[Richard Crawley]

Andy

what clutch unit are you running?

[Andy K]

Andy

what clutch unit are you running?

 

Hi. Standard Borg & Beck which has served me well for last 3 years. The jerky release bearing problem appeared spontaneously a good while after the car went back together, but was resolved completely by a cleanup. The problem was not present when the old g/box came out.

 

Andy

[Richard Crawley]

Hi. Standard Borg & Beck which has served me well for last 3 years. The jerky release bearing problem appeared spontaneously a good while after the car went back together, but was resolved completely by a cleanup. The problem was not present when the old g/box came out.

 

Andy

Hi Andy

Reason for asking is that I assume your aware that there was a batch of very duff B&B pressure plates going around a few years ago which just weren’t up to it. I assume you examined the release bearing, pressure & driven plates thoroughly for signs of damage before they went back in?

 

I’ve had problems in the past when re-using clutch components that looked perfectly serviceable, only to give problems once re-installed. Personally I now always replace the clutch unit if ever the box has to come out; I know it’s extra cost but I’ve found it’s not worth the hassle of having to haul the box out yet again in the case of problems.

[Andy K]

Hi Andy

Reason for asking is that I assume your aware that there was a batch of very duff B&B pressure plates going around a few years ago which just weren’t up to it. I assume you examined the release bearing, pressure & driven plates thoroughly for signs of damage before they went back in?

 

I’ve had problems in the past when re-using clutch components that looked perfectly serviceable, only to give problems once re-installed. Personally I now always replace the clutch unit if ever the box has to come out; I know it’s extra cost but I’ve found it’s not worth the hassle of having to haul the box out yet again in the case of problems.

Hello again.

too late to change the clutch......all screwed back together again!!!!

Clutch does now seem fine with no catching.

Swapped the top box for the one on the old unit. (Being of a nervous disposition, thought I should hang on to it for the time being.)

Gearchange now better, but still not perfect with 1st. 3rd OK.

Also, leftmost screw for setting detent on 1st/2nd screwed well in on new unit. This according to Tech CD and WS manual is not supposed to be like this, and I wonder if the reconditioners either didn't address this or merely screwed it in to get an adequate pressure on the ball bearing rather than shim the spring etc. Perhaps this is the underlying problem.....

Next step is off to someone locally who can have a look at the top cover for me, and set it up again properly.

(As long as it isn't the same lot that did the original "reconditioning"!) The local supplier apparently doesn't have any more to units to exchange another top cover from.

 

 

 

Andy K

[Andy K]

The next instalment..........

I decided to reuse the "new" selector box, taking bits if necessary from the original.

I got new springs for the detents, and on dismantling the "reconditioned" unit got all sorts of sludge coming out of the retaining bores for the detents as well as a well chewed reverse plunger. No effort had been made to overhaul this bit of the box methinks..........

All now back together, cleaned out,screws all flush and detents set at the correct poundage. (spring scales from hardware store £8)

The gearbox still baulks a bit going into 1st, and less often 3rd. I do wonder if this to do with the syncro rings and the rebuild. Clutch very slightly catchy at the bottom of its stroke but OK where it matters, picking up at the bite point smoothly.

Plan now is to see if the gearbox slackens a little with use. If not, out again after the Le Mans trip, warranty invoked and another attempt to sort. Might even get an independent opinion. New clutch etc at that point as suggested.

 

Bye for now

 

Andy K

[Richard Crawley]

The gearbox still baulks a bit going into 1st, and less often 3rd. I do wonder if this to do with the syncro rings and the rebuild.

Andy

There are also some distinctly dodgy, after market syncro rings around as well!

[Andy K]

Well, here I am again. Finally cracked and got a new clutch, release bearing and carrier and put ithem in prior to an excellent trip to the Classic Le Mans, and great fun going round the track.

However.........the malady lingered on, with a catchy clutch pedal, slowly getting worse as the mechanicals heated up.

So, back home and ordered the only bit that hadn't been changed that could be worn, the front nose thingy in the bellhousing. On removing the old thingy, signs of discolouration on the polished surface which did buff out, but nothing else. I had lightly sprayed this assembly with silicone, also the splines on the the input shaft of the box prior to assembly

This time, another good polish of the working surface of the thingy with 1600 dry W&D, some HMP grease and all together again...................

So far so good, very smooth, but I shan't hold my breath! I am getting quicker at this game each time.

 

The only other thing I noticed, was that being a little retentive, I replaced the paper gasket at the same time as the thingy. It certainly looked a little undersize, and needed coaxing to get its inner edge to lie flat around the bearing housing. I wonder if this creates a problem if you don't settle it before you tighten the thingy (OK, bearing carrier) down. Could it be causing the carrier to lie off the axis of the shaft? Or is this unlikely?

 

Finally, all this can't be affecting me too much, since I've just bought a TR6 as daily transport. Or perhaps I'm beyond help.