Gearbox-Help Please

[bourne17]

Over the winter I removed the engine and gearbox and had the box rebuilt by a local mechanical (lots of blood, sweat and tears!). I had a trackday today and all was going extremely well until the gearbox stuck in 4th gear. The clutch was working OK and I had a look at the selector and all seemed fine.

The gear is really stuck and I am not able to get the lever out of 4th. I am dreading the worst. Does anyone have any thoughts?

 

many thanks

[Stationary M25 Traveller]

See the current threads about selector seizing up - twixt gear stick and bearing - easily accessible on top of the gearbox once you take the tunnel top off.

 

edit - oh - you have looked at the selector - did you remove it ?

 

If not, then sounds ominous ?

 

Edited by - Stationary M25 Traveller on 3 Apr 2012 19:03:40

[bourne17]

Yes it does sound like the selector as there was no obvious noise from the gearbox, no crunching or strange noises. The selector lever moved freely but there may be another issue with the linkage. The car is back with the mechanic at the moment but he is scratching his head.

 

 

[andy_h]

Possibly a Snapped synchro ring.

 

 

[James_Russell]

I have snapped a selector rollpin before...?

[bourne17]

Would it still seize in gear if it was a synchro ring?

[Mankee]

Is it a 5-speed Type 9? There's a small bearing inside the input shaft that the mainshaft sits on. Is there a possibility that this has overheated, seized up and left you stuck in 4th? Could also be the roll pin as pointed out or syncro hub jamming up. Something isn't right though. Does the clutch still "work"? As in, it'll transfer drive when you lift the pedal up?

 

This is similar to what you'll see when you lift the lid. 4th gear is the bronze selector on the right and when 4th is engaged, the syncro hub moves to the right and links the input shaft directly to the mainshaft, hence the ratio of 1:1. Something is stopping you from returning the lever to neutral.

 

http://images56.fotki.com/v168/photos/8/42688/7812053/DSCF1335-vi.jpg

[6speedmanual]

Mankee is giving some good info and a nice piccy.

 

If the selector rod moves freely back and forth but it is still in gear, the selector disc is almost certainly liberated from the selector rod. Maybe if according to Mankee's photo the pin should be lockwired, your blood sweat and tears mechanic did not wire it in?

 

If the selector rod is jammed in 4th gear position it is more likely a fault on the sychro hub. They click into place (in gear) with small springs and tabs. one may have jammed or dislodged.

 

Anyway lid off and have a look. Is anyone able to state whether the lid is removable in situ? With some automotive "keyhole surgery" it may be possible to repair without taking 'box out. BUT... make sure any stray parts come out when you drain the oil!

 

In in doubt, pull 'box out! 😬 ☹️ 😬 ☹️ 😬 ☹️

 

Peter

[Mankee]

BGH say that lockwiring the selector block roll pin(s) is overkill. They supply a 4mm and 3mm roll pin "kit" for the selector block and they should never fall out or break if fitted properly, i.e. the split in the pins should be oriented in the same direction as the force applied.

 

The lid of the Type 9 box is removeable in situ, although it is a little bit of a squeeze. It was on my car anyway, as I took the lid off to suck all the oil out of it before taking it all out.

 

I had some missing blocker bars and broken syncro rings in my (ab)used spare gearbox. It still shifted gear fine on the bench and felt OK, but the bits of syncro ring and blocker bars attached to the magnet at the bottom of the box wasn't a good sign!

 

I have some spare blocker bars for 3rd/4th gear syncro and new syncro rings if you end up needing them. What did your mechanic renew during the gearbox rebuild?

[alan fensome]

Hi-What oil was put in after the work. I may be (and probably am) wrong but i heard some of the newer formulation oils eat the bronze in the gearbox.

hope it's something simple though

Alan

[richy]

*arrowup*It would have to be nitric acid to eat it after a couple of months

[bourne17]

Many thanks for your responses. Looks like I will need to get the box out and take it to Road and Race this time. I was hoping that it was only a selector problem but I dont think it is. Lesson learnt - always go with your gut feelings! I was originally going to take it to R&R but I changed my mind.

 

 

[bourne17]

Does anyone know whether it is possible to remove the gearbox without actually lifing out the engine? Car is S3 with K series and type 9 box.

 

 

[Stationary M25 Traveller]

Definitely not !

[bourne17]

Ok, clutching at straws.

[tiddy1]

Did it stop working soon after the rebuild ?, you may find that the big washer thing (technical term) with the slot in sticking up in the middle of the selecter, was not re-engaged into the slot it the gearbox lid when it was re assembled. it will then move out of place and jam everything

 

Simon

[bourne17]

Yes it did happen just after the build. Did you mean the big central washer, is it held in place by the lid?

 

[Grubbster]

Quoting bourne17: 

Does anyone know whether it is possible to remove the gearbox without actually lifing out the engine? Car is S3 with K series and type 9 box.

 

 

No but it does make it easier if you separate the engine and box in situ, then lift the engine out first and the gearbox after, need to put a stand or block under the bellhousing to support it.

[Mankee]

I took my engine and box out together, but people always have different preferences. I spent £20 on an engine leveller to move the weight of the engine and box around and it was an incredibly useful device to have. It should be useful for putting the whole lot back in, but I've not got to that stage yet. 😔

[bourne17]

Ok, have just been through the whole engine removal process and did use a leveller. I will split the engine and gearbox this time as I think this will be easier.

[Paul Deslandes]

The oil type issue is that you shouldn't use GL5 oil in boxes with brass/bronze parts, including Ford Type 9, or they will corrode. Stick with a GL4 oil, Redline MTL works very well - see lots of archive postings on the topic.

[bourne17]

Yes I did use MTL, I don't think the oil type is the issue.

[tiddy1]

Yes the big central washer fits into the groove in the underside of the lid

 

Simon

[Mechanical Moz]

Having had my gearbox (5 speed, 60k miles) jam in 4th at Cadwell, I've now got it out of the car and found that one of the blocker bars on the 3rd/4th synchro has a gouge in the top of it from the outer synchro ring.  Flicking it back with a screwdriver has freed the selector but obviously I'm not putting it back in like that.

So to a couple of questions.

I see places selling heavy duty blocker bars, are they necessary?  I get the impression they are less prone to breaking than the standard ones but are they more resistant to this type of failure?

Long 1st or full set of Tracsport ratios?  It's a 145bhp VVC K.  I guess that's more a case of how much I can justify spending to myself.

I'd like to put a fill hole in the lid and have seen a couple of posts where a threaded boss or nut has been welded on.  Is that really necessary or would a hole with a blanking grommet in achieve the same?  The lid has a small breather hole in anyway.

[Mankee]

Oddly, my mate also trolleyed his Type 9 recently, with a similar fault. It got stuck in 4th early in the morning, behaved OK-ish later on and then eventually failed towards the end of the day. Still had drive, but the box made some nasty noises and 4th crunched every time. We're thinking blocker bar or baulk ring failure.

When BGH rebuilt my Type 9, standard used but good blocker bars were fitted I'm pretty sure. They, as well as all components in a normal Type 9, will last a long while if treated with mechanical sympathy. Mine is 100% pure track use and I try not to destroy it.

As for ratios, like you say, how deep are you pockets and is it predominantly road use? Just waiting for Neil (7 Wonders of the World) to pipe up now and tell you to just stump up for the Tracsport cluster.