Silver 83 transmission rebuild

[evm1024]

With the engine and transmission out of the car I went ahead and opened up the transmission. No "known" problems but it has been sitting for 20 years or so and was driven hard and perhaps abused by the prior owner.

I will have a number of questions that I will need to ask after searching the board.

Right now the transmission is apart and in need of a bit more cleaning. The wear on the shift forks is clear. One has 7.36 mm on one side and 7.3 mm on the other. The other (3-4?) has 7.44 mm and 7.48 mm. The 5th-R has 4.71 mm - 4.27 mm and 7.8 mm on the reverse side.

Take a look here http://morganlefay.org/?q=transmission for the "root" of the rebuild photos.



Photos of the forks are here http://morganlefay.org/?q=shift-forks

Can anyone comment on the condition of the forks and of any of the parts that they see in the general photo?

[evm1024]

Oh, one question comes to mind. I did not see exactly where the 3 rollers came out from. And, I'm not finding a photo or diagram that illistrates this. Can someone point me in the right direction? As it is I will have to trial and error on assembly.

Ah, I think I get it. They go at right angles to the detent springs. They are safety devices that allow only one shift rod to be in gear at one time. It looks like the short one is between 5th-R and 3-4, the thin one is through the center of the 3-4 and the long one is between the 1-2 and 3-4 shifters.

When in neutral they are all lined up and have slack due to the recess cut in the shift rod. When any shift rod is in gear the detent is offset the the respective "roller" is pushed and takes up the free play. Thus the other shift rods cannot be moved.

[klweimer]

When I rebuilt my transmission, I replaced anything that looked worn (while I'm right here...), but I don't think your forks look too bad. Are they bent at all? Let's see what others think. I would spin all the bearings and see how they sound. I had some that were nice and quiet, and a couple that really growled. Clean them all well and look for cracking on the races with a magnifying glass. I would also spend the money on the good bearings if you have a choice. New synchos for sure.
The little rollers you mentioned are typically referred to as "beans" and you are correct, they are used to prevent multiple fork rods from moving at the same time. As I recall, they may not all be the same length, so double check that on assembly. Some transmissions also had another bean looking thing behind a switch that sensed when the transmission was in 3rd? gear. It was an emissions thing, but not used with the FI motors.
I assume you have the factory rebuild manual? Lots of good threads here for rebuilding, and I believe there are some Youtube videos floating out there as well.
Kirk

[evm1024]

Its out so replace is my thought exactly. Yes, a shop manual and a few books (Autobook 925 with a writup on dual IDF !) I've been reading the trransmission threads too.

I did not find any wear limit specs for the forks which may be moot. In general I expect to replace the syncro rings, springs, sliders and forks. Plus the roller bearing. Who sells "better" bearings and what to they get you?

Will do the visual inspection - I'm out of solvent but that is on todays list.

One of the forks looks unworn (7.48 mm) while the other 2 have wear. 5th has 0.66 and 1.07 mm wear. I could keep the sleeves - they have 7.36 and 7.48 mm slots and the teeth are not rounded off.

Thanks for your input!

[evm1024]

I got things cleaned up and they do not look so bad. The Syncros are more or less unworn except where the c-ring rides against the teeth. Here is a photo of the syncros.



And here is an out of focus look at the 5th fork in the slider showing around 1mm play.



Lastly just a photo of the misc parts cleaned up.



At this point I think that I'll only replace the syncros, their springs, the forks (the play in 5th worries me) and the roller bearing. Oh, I may replace the input shaft bearing because it sounds a bit noisy to me. Anything else that I should consider replacing so long as I'm in there?

Regards, Ethan

[klweimer]

It seems like when I did my rebuild, vendors offered some bearings as the OEM version and an equivalent generic version. I got one of the generic versions (Russian?) and it wasn't nearly as smooth new, as the original (SKF) was used. While I'm sure it would work OK, I stuck with the quiet one. I would also replace the ball and socket parts at the base of the shift lever. I think there is also a seal on the shaft that goes from the shift lever, through the extension housing and into the main box.
Once you get the box back together, you get to decide if you want to use GL-1 gear oil or a synthetic. I started with GL-1, but it was very stiff cold. I drained it and went with Redline MT-90. Viscosity is much more consistent, regardless of temp.
Kirk

[evm1024]

I'll go OEM unless I could get some ABEC-3 at a reasonable price (I use ABEC 5 or 7 in tape decks that I rebuild).

This car is the 5th Fiat I've owned (a super brave (miss that car) and the rest 124's). I expect to break in the transmission with GL-1 then switch to MT-90 (which I mostly have used in the spiders).

[evm1024]

I have a few choices for the input shaft bearing. The SKF 3 piece came with the transmission is likely OK but a tad noisy for me. How do 3 pice SKF and IRB with 11 balls compare to the Russian (Lada?) one piece bearing with 7 balls in terms of life and noise. Anybody have any thoughts on bearing selection?

Also, some of the bearings need to go in with a specific face "inside". Is it obvious on how to fit them? My docs do not give me any insight.

[klweimer]

I'd go for the SKF if the races look OK. Not sure about the "faces" on the other bearings. I don't recall worrying about that on any bearing that wasn't obvious.
Kirk

[djape1977]

plenty of sh** quality bearings out there, unfortunately i can't tell you which are ok.
if you manage to dig up any from old stocks they're generally good. even new skf can be noisy

[evm1024]

I ended up in deciding to reuse the existing SKF bearing. the races were a nice matte with the balls still shiny.

I've been pouring over the web, this site and my service manual to identify the stacking order of the various gears, spacers etc. Sadly I did not take any photos... My bad.

For the most part it is pretty clear but I do have some questions.

- are there any exploded views that are better than the service manual?
- How about photos from a few different angles of the stacking?
- any step by step photos? High resolution would be nice.

My specific question comes about with the spacers on the main shaft. My manual page 21-24 has an exploded diagram on the bottom of the page. Spacers 15 and 18 are listed but I appear to have a spacer and a spring washer. Which is which or have I mixed a few parts up?

The diagram on page 21-2 may answer my questions....

[grrrdot]

Here are some pictures I took when disassembling my trans.
Maybe it helps?
http://imgur.com/a/KdtKM

-G

[evm1024]

Thank you so much. They show what I wanted confirmation on. The spring washer goes between the mainshaft bearing and the reverse gear (#15 on page 21-14) and the thicker spacer goes on the prong side of the 5th gear hub.

Regards!

[evm1024]

I'm currently waiting for a few parts to show up from Midwest-Bayless that got stuck in a snowstorm in Utah....

The more I think about it the more I realize that the existing parts were for the most part in good condition. The only worn fork is the 5th-R one. But I went ahead and changes out the forks. The sliders are good with the most ward one shown in this photo. I have 2 new coming from Midwest-Bayless.

I have (as noted above) decided to reuse all bearings except for the roller bearing. I have a spare input shaft bearing.

Now that I am getting clost to putting it all back together I am wondering if I should use the original Syncros or go with the one I get from Vicks. Any thoughts?

The photo shows the original syncros and the sliders. The slider on the left is the most worn. The on on eht right shows how both the other sides look.

[klweimer]

I'd go with new synchros, as by design they are the wear item inside the box. When I rebuilt my transmission a couple years ago, I had ended up with 3 transmissions worth of parts to work from. I took all the low wear items and built a second box and traded that for a roll bar. That way, I didn't feel like I was tossing good parts in the trash. Rebuilding the second one was a piece of cake, after building the first one.
Kirk