transmission rebuild progress

[wannabfast]

well i am rebuilding 2 transmissions this next coming year, and i wanted to document the progress and pictures of everything, as i dont normally do that, just for the record

transmission one: issues, slight whine in 5th gear
i suspect one of the bearings on the main shaft or secondary shaft is the culprit but it could be worn gears as well

transmission on table, and 2x4's to lift it up from the studs

axle stub out, looks like i will need a new seal

5th gear sets, look ok, the synchro spring looks iffy, possible cause of the whining, teeth on the synchro teeth looks slightly worn, but not so much that it would be grinding(not present)

i forgot the socket (size) for the nuts on the end of the shafts, so im calling it a night:mallet:

 

[EricH]

How did you end up pulling the axles?

 

[wannabfast]

borrowed a slide hammer with a 3 jaw clamp

 

[Rupunzell]

That would be a 30mm socket.

Use a 4mm wide cape punch to free the nut's deformed area before removal.

The nuts comes off easy with an impact wrench.

Select a gear and use an old clutch disc to hold the shafts while removing the nuts on the ends. This will also work when torquing these nuts to the required value.

More hints and what to look for as this transaxle dis-assembly progresses.

Bernice

i forgot the socket (size) for the nuts on the end of the shafts, so im calling it a night:mallet:

 

[eflexter]

!

Again, when you pull out the three springs that are the shaft detents (under the little metal oval shaped cover on the side of the tranny) pay attention to which one goes in what hole. They aren't the same in the five speed, and the manual doesn't help.

 

[wannabfast]

Again, when you pull out the three springs that are the shaft detents (under the little metal oval shaped cover on the side of the tranny) pay attention to which one goes in what hole. They aren't the same in the five speed, and the manual doesn't help.

well i compared them, and they were the same length and thickness, with the same rate of coil, so i believe all of those springs are the same, or at least similar

 

[EricH]

well i compared them, and they were the same length and thickness, with the same rate of coil, so i believe all of those springs are the same, or at least similar

Hmmm... Shouldn't be... Fifth/reverse is supposed to a bit shorter and stiffer.

On a four-speed, not only is reverse shorter and stiffer, it's a different color, dyed green instead of blue (or the other way around), at least on the last few that I've taken apart.

 

[Bobr]

How did you test it being out of the car?

I ran that trans in the car on jackstands and it all seemed OK. I was not sure about it with a load. I know reverse whined pulling the car. 1st gear was quiet. Thats the extent of my driving that trans. The original owner said it had no problem was a bad clutch slave that I replaced...
Anyhow you are in for a great challenge.....:headbang:

 

[wannabfast]

well reverse is supposed to whine a little as it is a straight cut gear

but it does need new gaskets though, it oil residue was probably caked on if you hadnt pressure washed it

the release fork was rusted together pretty good, not sure i can pop that sucker out just yet
*edit* bob i thought you said it whined in 5th gear?

 

[Bobr]

Nope....It's the one in my 81 the does that.

Never had a load on the 80 trans you got except for backing it out of the garage and pulling it down the street and running it back a few days later. I ran it with the suspension loaded and the wheels free spinning.....

 

[wannabfast]

got the case apart by hand with help from a friend, took the shift forks and shafts off, the 5th gear reverse shaft was dimpled at the end causing quite a bit of effort to remove, it should have slid out easy but it didnt

ill post pics a little later tonight

 

[wannabfast]

some pics
case open

reverse idler looks good!

more gears

that dont look right

small knick on 1st gear

scoring from the knick on the 1st gear knick and crack in the reverse idler shaft hole

reverse idler, looks fantastic

oh the carnage... time to clean up

 

[wannabfast]

hmmmm

 

[Black-Tooth]

Whoa... that can't be good! nt

.

 

[Dan Sarandrea (Phila)]

Bent reverse shaft?

Known to be an issue, addressed in the last iteration of the 5 sp with a larger diameter shaft...17mm or maybe 18mm IIRC.

 

[wannabfast]

yup thats the reverse shaft

 

[Rupunzell]

16mm reverse shaft.. and it's bent. Common problem and part of why these transaxles pops out of reverse. later versions have a 18mm shaft and matching 18mm clearance hole reverse gear. A FIAT running fix for this problem.

It is likely the reverse gear shaft boss cast into the case is cracked or part two of the reverse gear problem. Get this welded up and bored to size (if required) if cracked.

What does the internal magnet look like? Are there any large metal bits or just fine metal particles?

Do replace all the bearings with FIAT OE or similar quality brand (SKF, FAG or similar) brand and type. The roller input shaft bearing has been replaced with a ball bearing on later transaxles. Replace 1st gear that is chipped. Check the 1-2nd syncro gap which indicates wear. Replace 3rd gear syncro, inner spring bands and locating dogs if needed. Replace 3-4th gear/slider if worn. The little teeth will be rounded when worn, they will be chipped and fracture if abused. 4-5th gear is usually OK. 3,4,5th gear uses Porsche type syncros, 1-2 is modified cone syncro. Do check the condition of the shift forks and the clearance between fork and slider sleeve groove. If the forks are worn, replace them. If any gears need to be replaced, make sure they have the same # of teeth as there are differences depending on when the gear box was made.

If the diff carrier bearings are replaced, bearing pre-load will need to be adjusted by altering the shim thickness if needed. The diff carrier bearing cover will likely be bent very slightly at the bolt hole area due to the loading. Chuck then in a lathe and surface them flat if required before adjusting the bearing pre-load.

And, the stud for the lower mount must be sealed or it will leak transmission oil. This is why there are two M8 bolts and one M8 stud for that lower mount.

Otherwise, this looks like a pretty typical 5 speed project.


Bernice

hmmmm

 

[wannabfast]

It is likely the reverse gear shaft boss cast into the case is cracked or part two of the reverse gear problem. Get this welded up and bored to size (if required) if cracked.

What does the internal magnet look like? Are there any large metal bits or just fine metal particles?

Do replace all the bearings with FIAT OE or similar quality brand (SKF, FAG or similar) brand and type. The roller input shaft bearing has been replaced with a ball bearing on later transaxles. Replace 1st gear that is chipped. Check the 1-2nd syncro gap which indicates wear. Replace 3rd gear syncro, inner spring bands and locating dogs if needed. Replace 3-4th gear/slider if worn. The little teeth will be rounded when worn, they will be chipped and fracture if abused. 4-5th gear is usually OK. 3,4,5th gear uses Porsche type syncros, 1-2 is modified cone syncro. Do check the condition of the shift forks and the clearance between fork and slider sleeve groove. If the forks are worn, replace them. If any gears need to be replaced, make sure they have the same # of teeth as there are differences depending on when the gear box was made.

the synchros all look good, its just a knick in a tiny part of one tooth on the 1st gear i was going to file it down a little bit as it doesnt protrude into the teeth itself

 

[EricH]

the synchros all look good, its just a knick in a tiny part of one tooth on the 1st gear i was going to file it down a little bit as it doesnt protrude into the teeth itself

I'd be inclined to replace the third gear synchro no matter how good it looks.

 

[eflexter]

YES!!

Replace the THIRD GEAR SYNCRO!! As stated above. I didn't replace mine because it looked and seemed to function perfectly, but it turned out to be weak.

Now I'm gonna have to pull my tranny again just to do the darn syncro.

Don't depend on visual inspections, just replace everything you can afford to.