Good morning Fiat Forum

I am once again after a bit of advice. I am currently in the process of changing the drive shafts on my 500R and successfully managed to remove the engine and gearbox at the weekend (pretty chuffed with myself). After following a very useful step by step guild I have also managed to split the diff and remove the old, totally knackered, drive shafts All pretty straight-forward so far. Anyway, as I've got the gearbox out I thought i'd remove the inspection plate to have a look inside the box and instantly noticed that the little gear, which I believe is either 1st or reverse, seems pretty mangled. I also notice that there was quite a lot of metal particles in the bell housing and attached to the sump plug. As far as I can tell all the bearings look intact. I haven't driven the car for many miles yet but up to press I haven't had any noticeable gearbox issues e.g. no trouble selecting gears and she's not skipping out of gear. I suppose my questions are:

1. Am I right in thinking the gear is worn and shouldn't look like that?
2. If it is worn, how bad is it?
3. If it is bad what are my options for replacing?
4. Is this something an average DIY mechanic can do?

At the moment I'm thinking of just replacing the drive shafts, rebuilding everything, putting the engine back in the car and enjoying driving her throughout the summer. Basically, working on the principle, "If it ain't broken don't fix it!" However, if is totally knackered and there is an easy fix it would make sense to do it know while I've got everything in bits.

What do you guys think?

They all suffer from this over time. Replacing 1st and reverse is not too difficult and costs about £150

This is a comparison between my worn and new parts.
MAL_6741 by Peter Thompson, on Flickr
It's a hard one to call; when you are at that stage and obviously are that competent I would say it makes sense to repair it properly. But to some extent you would be doing it to prevent things from moving to the stage where it won't stay in first or reverse gear. I guess it's OK at the moment and they are all noisy in first and reverse..even with band new parts...thats down to design.

I'm no gearbox expert but it doesn't look too bad to me. I would drain out the old oil and clean it all up best you can. Fill with fresh oil and enjoy driving over the summer. Only go into first gear when the car is completely stationary and be as gentle as you can. The worst that can happen is you start struggling to get it into gear and that would be the time to replace the gears. No problem just remove gearbox and you are already an expert on that now

I'm on the fence with this one.
If it doesn't jump out of first and you can select first easily then you should get away with an oil change as Damian suggested.
However there is quite a lot of ware on the gears and that is evident by the amount of swarf in the box. Bare in mind that has all been swimming in the oil, it is likely to have gone through the bearings.
If you are going to replace the gears I would be tempted to change the bearings to make sure everything is ok. Or at least clean them and check the seatings are ok.
The gearbox is quite tricky to rebuild due to the lack of room in the box. But saying that if you are competent and confident then its quite straight forward and after you will have similar feelings to the first time you mastered the Rubiks cube

If you have split the diff and changed the driveshafts then you have already completed one of the harder jobs. I hope that you marked the position of the drive shaft bearings as that sets the backlash for the diff. Any further work on the gearbox would just require following instructions as per the Haynes manual or similar. A bit like grown up Lego. If the car drove well and there were no problems getting 1st & reverse and it was not very noisy in those gears you should be OK. I have 4 spare 500 gearboxes here including a good used 1st & reverse set up should you need it.

Paolo66 said:

I'm no gearbox expert but it doesn't look too bad to me. I would drain out the old oil and clean it all up best you can. Fill with fresh oil and enjoy driving over the summer. Only go into first gear when the car is completely stationary and be as gentle as you can. The worst that can happen is you start struggling to get it into gear and that would be the time to replace the gears. No problem just remove gearbox and you are already an expert on that now

Click to expand...

I agree with this completely.
John

Morning Toshi 975

Thanks for taking the time to get back to me, its much appreciated. I can confirm that I did mark the position of the drive shaft bearings when I was slitting the diff. I actually followed a very useful step by step guild that I found on the forum. As I mentioned in my original post I haven't done a huge amount of miles in the car yet (potentially on 50 miles), but so far I haven't had any really issues with selecting either 1st or reverse and she hasn't jumped out of gear either. She does sound pretty loud when I set off in 1st but as I haven't driven another 500 I'm not sure if its normal or not, hope that makes sense.

Out of interest where are you based and how much would you want for the 1st & reverse set up and potentially a full gearbox?

Geoff
1973 Fiat 500R

First and reverse being noisy is not primarily a fault, because the gears are cut in a deliberately simple way which makes a noise even when new.
If you've only done 50 miles I would get it back together and start driving. then you will know for certain how liveable-with it is. Ideally if you can get a spare gearbox I suspect you will be planning to overhaul that so you have a-spare-part-in-waiting.

I am located in Chesham , Bucks where I know of 3 other Fiat 500 owners in town. I have just realised that you have a 500R which has the syncro gearbox and the boxes I referred to were the earlier non syncro type. I do have one rebuilt syncro gearbox , two part rebuilt and a huge pile of gearbox parts

Hi Toshi

Yes its the synchro gearbox that I would be after. Taking the advice of the other members I think I'm going to simply rebuild the box and drive the car over the summer. I know I'm going to have to overhaul the gearbox at some point so its useful to know you've got a good selection of parts I might be able to buy off you. Once again, thanks for the advice.

Geoff

Idleboy08 said:

Morning Toshi 975

I actually followed a very useful step by step guild that I found on the forum.
Geoff
1973 Fiat 500R

Click to expand...

Can you please give me the link of this step by step guide because i cant't find it. (Yeap gearbox overhaul on the way)

Thomas

I agree with the bulk of the advice---"if it aint broke, don't repair it". Fit the new drive-shafts, put it all back together and use it. At least this way you will get a summer's use out of it. If it DOES need new gears (and my '126' box is noisy in 1st), wipp it out as soon as you take off the road for the winter and use your time over the winter to overhaul the gearbox (as well as any other jobs required). As 'Paolo66' suggested , only select 1st gear when the vehicle is stationary--which you should be doing anyway because synchro is only on 2nd, 3rd and top gears---not on 1st gear. It also pays, when you are going to select 1st gear to momentarily slip it into 2nd, and then into 1st--this way you will align the 1st/2nd gear hub, making the selection of 1st gear easier.
A cleanout of as much of the old oil as possible, along with any muck in the box is very sensible. It might also be wise to refill the box with something like "Red Line" 75/90 gearbox oil--it seems to have a good reputation with gearboxes that are getting 'a bit long in the tooth'. I would also suggest that you refill the gearbox with oil prior to fitting it into the car. Leave the top cover off, make sure the gear-box is level, remove the refill/level plug (on the side of the gearbox, between the bell-housing joint and a drive-shaft housing), fill the gear-box until the oil just starts to come out of the refill/level plug. Refit the plug (tight!) and then refit the top cover. Doing it this way is a lot less hassle than trying to refill the gearbox than when it is in the car. You will probably find the level plug very tight. An easy(ish) way to remove the level plug is to use a 1/2 drive, short extension put onto the plug backwards (i.e. with the square 1/2in drive hole on the plug), and a 1/2in-13mm socket on the 'male' end of the extension to turn it--the plugs can be VERY tight.

Hi Geoff, I have just refitted my box after a strip and rebuild following a hi-ratio pinion and crown wheel upgrade and new drive shafts. Notwithstanding what everyone else has said with the wear you have I would council you to strip it as per Haynes and clean everything most thoroughly, be careful with the synchro units and bearings and the pinion spacers, replace ALL seals and top it up as Hobbler says with 75/90 from your local motor factors. You should be ok for the summer at least

Ian.