Testing rebuild transmission

[18Fiatsandcounting]

That's a good one Steiny! I know of someone who forgot to put the oil filler cap on the camshaft cover after adding oil. This person drove about 30 miles before the low oil pressure light came on. Turns out a lot of oil comes out of that opening in a short time, with most of it ending up in the engine compartment.

OK, OK, I confess! It was me! Taught me a lesson.

-Bryan

[rjkoop]

So tested it today... finally. After I remembered to hookup the started wiring (couldn't figure out why the red dash light wasn't coming on and it wouldn't start... doh!) she started great. Let it warm up a bit and went through all the gears (up to about 4000 rpm). There was... no smoke, it shifted great and no grinding between gears. Phew! So I think my rebuild is fine. Happy about that for sure.

Still a small leak from the pan but I think I know how to fix that.

Thanks for the help and encouragement.

Richard

[18Fiatsandcounting]

So I think my rebuild is fine. Happy about that for sure.

Awesome Richard, glad you got that bad boy running again! Let us know how it progresses.

-Bryan

[davidbruce]

That's great to hear Richard. Thanks for letting us know the outcome.

[Nut124]

Koop, I hope it runs great.

I have a trans in my garage that I took out for hard 2nd gear shifting. I would like to try and fix it.

What did you use for guidance, direction when assessing condition of parts, rebuilding?

[rjkoop]

Koop, I hope it runs great.

I have a trans in my garage that I took out for hard 2nd gear shifting. I would like to try and fix it.

What did you use for guidance, direction when assessing condition of parts, rebuilding?

My big mistake was not taking enough pictures while taking it apart and laying out the parts EXACTLY the way they came out (eg. orientation). There are so many things that are very similar but aren't the same. I kind of took the approach that I'll take everything apart, generally put things in order but the manuals for putting back together are a little vague. Also get the right tools (eg. bearing puller) helps a lot. Rather than forcing/hammering things.

So when I 1st started I used the International Auto Parts manual and online resources. I then realized (1/2 way through the assembly) that I had a Fiat Haynes manual that had a lot more detail and switched over to using that one instead. Helped a lot!

Richard

[Nut124]

Richard, thanks for the info.

Did the trans have a problem before you rebuilt it? What parts were worn out and what did you replace?

Were the parts readily available?

[18Fiatsandcounting]

I have a trans in my garage that I took out for hard 2nd gear shifting. I would like to try and fix it.

When you say "hard shifting", do you mean it grinds gears when you shift into second, or it is just physically hard to push it into 2nd gear? The former is likely a worn synchro or shifting collar, while the latter could be everything from the wrong transmission oil (especially when cold) to something binding in the shifting mechanism from the shift knob all the way to the internals of the transmission.

As we speak, the transmission for my '69 is completely torn apart and laying on my workbench, so I'm happy to offer advice on how it goes back together. It is a rather intricate device, but it's also rather amazing in its design and space efficiency. Works quite well when everything is as it should be. I'm now awaiting on about $1000 worth of parts for a complete rebuild.

-Bryan

[rjkoop]

Quick question...

Anyone happen to know the size of the bolts on the transmission/bellhousing cover plate (at the bottom of the bellhousing) bolts? I know there are 4... 2 larger ones and 2 smaller ones. Can't find them.

Richard

[tima01864]

M6 M8

[18Fiatsandcounting]

Tima has it right: M6 x 1.0 by 1 cm for the smaller, and M8 x 1.25 x 1.8 cm for the larger. I just verified on mine, as the transmission is on my workbench in various pieces, along with all the other loose ends like that cover plate...

-Bryan

[Nut124]

I have a trans in my garage that I took out for hard 2nd gear shifting. I would like to try and fix it.

When you say "hard shifting", do you mean it grinds gears when you shift into second, or it is just physically hard to push it into 2nd gear? The former is likely a worn synchro or shifting collar, while the latter could be everything from the wrong transmission oil (especially when cold) to something binding in the shifting mechanism from the shift knob all the way to the internals of the transmission.

As we speak, the transmission for my '69 is completely torn apart and laying on my workbench, so I'm happy to offer advice on how it goes back together. It is a rather intricate device, but it's also rather amazing in its design and space efficiency. Works quite well when everything is as it should be. I'm now awaiting on about $1000 worth of parts for a complete rebuild.

-Bryan

Bryan, I very much appreciate the offer to help.

In the old trans, there was grinding upon attempting to shift to 2nd. I drove that trans hard for 20 years.

How do you assess whether or not the bearings need to be replaced? Or just do it while in there?

[18Fiatsandcounting]

In the old trans, there was grinding upon attempting to shift to 2nd. I drove that trans hard for 20 years.

How do you assess whether or not the bearings need to be replaced? Or just do it while in there?

Yep, grinding definitely means your synchros are not as fast as you are. If you slowly ease it into gear, sometimes you can avoid that "grind me a pound while you're at it" sound every time you shift, but few of us on this forum would put up with that for very long.

As to bearings: The front input shaft bearing had obvious scoring on the races, so that will get replaced. The front and rear layshaft bearings appeared good, but the center one had some radial play, maybe 0.001" or so, so I ordered a new one of those. The mainshaft bearings appeared good, but I did order a new needle cage bearing for where the front of the mainshaft inserts into the rear of the front input shaft assembly. Since the transmission has 170K miles or so on it, I went ahead and splurged for new shifter forks, shift collars, synchros, synchro springs, etc. All of these appeared to be in good shape, so I will save the parts for another transmission where that is not the case. There are differences in bearings from one model year to the next, but my understanding is that the shift forks, collars, etc. are the same year to year.

If anyone else knows a good way to check the bearings, let us know. In my case, everything looked in excellent shape, but I'm no expert on this.

-Bryan

[rjkoop]

I did synchros (I had grinding between 1st and 2nd gear unless I let the revs come down), shift forks for 1/2 and 3/4, bearings for the ones that had play or didn't spin smoothly (not many had to be replaced and the bearings are expensive - I replaced the needle cage bearing and I think one other one), the input/output shaft oil seals and of course gaskets. That's about it. For the gaskets I had leaks using the paper ones and then I used Ultra Copper on the bellhousing and transmission pan instead. Now no leaks.

Everything now buttoned up. Even got the stripped transmission/bellhousing inspection place bolts done tight using a helicoil for 2 of them.

All good and ready for an actual road test when the rain stops in Ottawa.

Richard

[rjkoop]

Nice weather here today so took it for a test drive. Accelerated hard, went through all the gears up to about 80 km/h, tried reverse and used the clutch to slow down the car (normally I don't but just wanted to ensure there were no noises)... Everything worked perfectly. So I'm happy that my rebuild work was good.

Thanks for everyone's help!

Richard