I have acquired a 2nd hand 2004 gearbox with just over 30k miles on it. Primarily it was £60 worth of fun to strip, pull apart and mess around with whilst the winter is here however ..... My own car ( 2004) has done approx 78k miles and has always been noisy from the secondary reduction area, tested this by driving around with the gearbox weatherseal and console removed and confirmed this.


Today i'm going to clean up and inspect the potential swap out part but the question I have ...... Is it a straight job of unbolting mine from the car and swapping over to the replacement part? Are there any bolts / washers / seals that should be replaced due to them being crush fit or single fit parts? If i swap the part over with no need to replace bearings, is it worth packing the bearings with high temp CV grease or would this contaminate the gearbox oil?

The bigger picture is that the new box has done half the mileage of mine and is only with me because the previous owner hadn't the time or need to sort out the noisy primary input shaft bearing. He used it for a while and confirmed that the synchros were all good, it was only removed and replaced with his original box because of the input bearing noise. I realise the noise may mean bits of bearing have been circulating the box so there may be longer term issues. I know this is usually a big issue because it means removing the box from the car and stripping the box to replace it. However that's not an issue for me as it's sat on my garage floor.

Would I be better off getting the primary input shaft bearing replaced, having the new box checked, cleaned, oil filter screen cleaned and pump checked then rebuilt as a good box and then just swap the whole thing over to my car.

My current box doesn't crunch 1st to 2nd or 2nd to 3rd and doesn't jump out of gear, the only issue i have is a noise one and i'm wary of making it into something more than it currently is.

Sorry for the ramble .. i've been up too long and have had too much coffee

 

I wouldn't do things by half. I had what I thought was a noisy secondary so I purchased the bearing (3 I believe) and output seal and rebuilt it. Not a major job although one part required a press to remove a bearing. Anyway, turned out the noise was coming from my diff but hey...

What I'm saying is it's not a big job and it doesn't introduce any unknowns. mean time you can rebuild your spare block.

 

I'm guessing it's probably 3 to 4 hours labour to replace the bearings in the main box and clean it up - assuming it's done by someone with a press who knows what they are doing ( not me I hasten to add).

I've had a proper look at the secondary area this morning, cleaned it with degreasant and let it sit draining for half an hour - nothing nasty fell out and all the bearing faces ( that i can see) all look in good condition. Something tells me those bearings need packing with high temp grease though ....... Honda look to have been fairly stingy with whatever they originally used.There's quite a bit of 'ticking' but that sounds like dry bearings and from looking at it, it has to be torqued up correctly 'in situ' for everything to align correctly.

It can't be more than an hours labour to get a shop to check and service the bearings in the secondary output box?

 

Stop listening to this Something
Grease does not belong in a gearbox.
A gearbox with - and this is not that common - an oil pump.

 

Including the secondary output shaft area? I don't see any way for oil to make its way there from the main gearbox or are there oil pathways contained inside the housing?

 

Recleaned with WD40 and you're quite correct, there is an oil line to the rear of the lower outer bearing shell and i assume - judging by the amount of WD40 that disappeared down it ... the secondary shaft is hollow or has holes along it and acts as an oil path to the rear bearings too.

The whole thing now spins beautifully with a nice clean 'ssssshing' sound.

The thing i now don't like the idea of is putting a lower mileage secondary housing on an higher mileage box as the bearings and shells won't be run in together and i may introduce more noise. Common sense says get the complete spare box rebuilt and checked and fit it as one unit. I can then flog mine on complete once the swap is done.

With gearboxes seemingly going for £400 upwards, bearing in mind i only paid £60 for this one - spending an extra £200 on top of that to have a known good one is money well spent, whether i end up keeping it as spares, fitting it .... or selling it on.

 

If you want a quick and nasty you could swap the rear housings over. Just make sure you swap the bearing shell out the back of the gearboxes so you keep the bearing parts together.

Before you pull the lot, run it on a hoist and use a stethescope or screwdriver in your ear to listen to the gearbox and diff casings. Just make sure you are climbing up the right tree.

 

You sure it's not the secondary shaft bearings? While the secondary shaft is oil fed, it's not very well done. Those bearings are known to fail. I had to swap mine at around 110k.