Rebuilt gearbox??

[maxm50]

The rebuilt trans was shipped to me with this weird wrapping of tar covered by thick aluminum foil - extremely difficult to get off. After trying all the solvents I have, gasoline, heat gun, picking with pliers etc, I found that gasoline and also Gunk Original dissolve it but requires many repeat applications.

https://drive.google.com/file/d/1PvNEm- ... sp=sharing

Sounds to me like the previous owner covered the transmission in Dynamat (or something similar). It’s a thick layer of black tar-like substance with a thick aluminum foil backing. It’s used for sound deadening body panels. Perhaps the PO was trying to quiet a noisy transmission. Clearly they didn’t understand the difference between sound dampening vs sound absorption... but I digress.

Anyway, if that’s what it is, I understand why it’s such a pain to remove. That stuff is NASTY. It’s applied with a heat gun, so that’s probably a great way to remove it, too... along with thick gloves and a couple of paint scrapers.

[18Fiatsandcounting]

Maxm's explanation makes a lot of sense, and I'll bet that's it. I did a quick search on Dynamat, and it's butyl rubber bonded to aluminum foil. Butyl rubber is what they make bicycle inner tubes out of, among many other things.

Solvents for butyl rubber would be toluene (better) or acetone (might work). Nasty stuff, so I'd wear gloves and do the work outside, if you go this route.

-Bryan

[MadBeez]

So, I got almost all of the tar off of the trans (thanks Bryan for the kerosene tip)

I replaced the rear seal on the rear housing and then noticed a difference between the speedo gear drives - the rebuilt one does not always turn when you turn the out put shaft and the lowest gear that engages the speedo gear is more forward than the one on the original allowing the ball bearings to show on the rebuilt one. (see pics) Is this normal?

I'm still looking for a way to id the year of the rebuilt trans. It appears that it matters for the output shaft spring (or no spring) and the rubber bushing. Csaba tells me that I need to count the teeth on the input Lay Shaft and the teeth on the input shaft receptacle but after researching I can't figure out what a Lay Shaft is.

Thanks, Rich.

https://drive.google.com/file/d/1U8Q4En ... sp=sharing

https://drive.google.com/file/d/12rbaUt ... sp=sharing

https://drive.google.com/file/d/1BpQUe7 ... sp=sharing

[18Fiatsandcounting]

Rich, I do agree that the speedometer drive looks a little "off". I'm no expert here, but I do know that the different model years had subtle differences in the speedometer drive (different tooth count, mainly). Perhaps you've got a mismatch.

The "Layshaft" is the foot-long shaft that runs parallel to the main shaft of the transmission. The main shaft is the one that begins with the input from the engine and ends with the output shaft to the rubber donut yoke. The layshaft has 4 gears on it and is situated below the main shaft when the transmission is upright.

I "think" what Csaba is asking you to do is to count the teeth on the first gear on the input part of the main shaft (closest to the engine), and also the teeth on the corresponding gear on the layshaft. Perhaps this is a way of identifying which transmission you have?

-Bryan

[aj81spider]

This thread

http://www.fiatspider.com/f15/viewtopic ... on#p297373

provides a little bit of information about transmission gearing differences. I'm guessing that some of the gearing differences also coincided with housing changes.

Doesn't answer your question about the layshaft, but may point to why that's a way of identifying the transmission.

[18Fiatsandcounting]

This thread

http://www.fiatspider.com/f15/viewtopic ... on#p297373

provides a little bit of information about transmission gearing differences. I'm guessing that some of the gearing differences also coincided with housing changes.

Since there is a difference in first gear, and these would be the gears on the main (input) shaft and layshaft that are closest to the engine, maybe this is what Csaba was referring to, in terms of distinguishing between transmission models?

-Bryan

[MadBeez]

Ok, so I've got the gearbox back together (damn, I just noticed that I forgot the gasket on the speedo gear housing so there's that) I went through the gears and they seem to act correctly and now I know that it's a "pull-up" for reverse gearbox that gives me more to go on as to the year.

I'd like to lubricate the lower ball of the gearshift mechanism with some lithium spray grease or whatever you'd recommend. Does this area fill with oil when I add the oil back into the box? And what oil do I use - I've read a lot of posts but it wouldn't hurt to have 4th or 5th opinions.

Next up is to remove the rest of the motor from the engine bay and start cleaning the bay up and painting it (probably black to match the color of oil)

Thanks for all the help so far!

~Rich

[18Fiatsandcounting]

I'd like to lubricate the lower ball of the gearshift mechanism with some lithium spray grease or whatever you'd recommend. Does this area fill with oil when I add the oil back into the box? And what oil do I use - I've read a lot of posts but it wouldn't hurt to have 4th or 5th opinions.

A mad plan, MadBeez! But a good one. And by the way, I "think" the early model spiders were pull up whereas the later ones were push down, and that transition happened in the mid 1970s. So, if yours is pull up, then it's likely an earlier model. But, opinions seem to vary on what I just said, and there always seem to be exceptions.

To answer your questions, I would use something a little more robust than spray grease. I usually just use a half teaspoon or so of axle bearing grease on the lower ball and its cup. And on the area where the shift linkage goes through that collar that connects to the rod into the transmission. No, this area does not fill up with oil, although you may get a little oil up in there. Not much, maybe a couple small puddles

As for transmission oil, what you want is an oil that is not harmful (corrosive) to the soft brass synchronizers. These are often referred to as "yellow metal", and modern transmission fluids like GL-5 contain sulfur additives that react with the brass (i.e., not good). Fiat specified GL-1, and some stores still carry this or you can order it online. Some people use a mineral oil based tractor oil for old Ford tractors. Some people say GL-4 is OK, but I've always been a bit skeptical of this. You could use a synthetic oil, but the seals in the Fiats transmissions were not designed for synthetic oils and they can start to leak over time.

So, in a nutshell, GL-1 transmission oil would be the best, mineral based oils are likely OK (if the right viscosity), but modern oils, especially synthetic, can be problematic. These of course are my opinions, and you will get other opinions if you ask around.

-Bryan

[MadBeez]

Thanks Bryan,

I settled on Pennzoil Synchromesh which is a GL3 manual trans oil. Couldn't find GL1. Here's the info I found on GL3:

"GL3 is the next level of performance and has very limited applications. Mainly specified for French and Italian (Fiat & Alfa) cars which had very soft synchromesh. It has very low EP (extreme pressure) performance and does not contain the concentration additives used in later engines. We would recommend our product Millitran 4, SAE 50 for these applications."

Got another question - do you know what this tool is? For compressing the valve tappet?

https://drive.google.com/file/d/180gFCT ... sp=sharing

[18Fiatsandcounting]

I didn't know GL-3 was still available, but no matter, this would seem to be what you need.

As far as the tool, that sorta looks like a Fiat valve adjustment tool, but I'm not positive. Vick Auto sells one that looks similar:
https://www.vickauto.com/FIAT-PARTS/FIA ... KU-65-2521

I guess the idea is that you wrap the curved part around the cam and use the edge of the curve to depress the bucket so that you can pull out the shim. Maybe others will recognize it and give a more definitive response.

-Bryan

[dinghyguy]

I believe it is a wrench for some special threaded nut that is round and has a hole in the side. the idea being to put the tip in the hole and then you can spin the round nut. Not sure where on a fiat it might fit though.
dinghyguy with the new garage.

[redcars]

I use a tool like that to adjust my coil overs.

[MadBeez]

Thanks, when I get to the shim adjustments I'll see if it will work without scraping anything up. It looks like it might work for that.

Another question for ya - I got some new motor mounts and when I took off the mounting brackets, I didn't pay attention. I thought they were both the same size but they're not. Can anyone tell me which side of the motor the taller one goes on?

https://drive.google.com/file/d/1KG-GHj ... sp=sharing

[18Fiatsandcounting]

Another question for ya - I got some new motor mounts and when I took off the mounting brackets, I didn't pay attention. I thought they were both the same size but they're not. Can anyone tell me which side of the motor the taller one goes on?

Just going by memory here, but I think the earlier spiders (including your '71) had brackets that were the same left to right. My '69 and '71 both have the same size brackets (although there is a left and a right symmetry to them). Later model years had different mounts for different size engines and/or other items attached to the brackets.

So, I'm guessing someone messed up the original mount and put in a replacement from a later model year. I'd call one of the Fiat vendors and see if they can help you out.

-Bryan

[MadBeez]

Hmm,

Before I cleaned them up and painted them, they looked to be original - same amount of crud on both and the mounts themselves both looked identically aged. I'll contact Bayless (where I bought the new motor mounts) and see if they can tell me.

Thanks, Rich.