transmission rebuild question

Maintenance advice to keep your Spider in shape.
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timspider

transmission rebuild question

Post by timspider »

I'm just about to get my transmission out after a very long extraction process. I've got the new clutch components I need (I hope) but I've got a question on the tranny.
The transmission was pretty smooth when I got this car a year ago with 85,000 miles on it. I've since put anther 10,000 on it and new just in the last weeks once the clutch started to fail is that 4th gear starting popping out. And it was stuck in 4th and very difficult to get out once I was in. Other gears seem ok.
So my question, wouldn't this be a good time for a rebuild?
Or just get 4th gear fixed (sounds like may be a worn fork from something I read?
I don't have the budget for it right now, but with cold weather coming, I have time.
And with the major pain this is to remove, it feels like a good time to breath some life into this 95,000 tranny before re installing.
Given that scenario, what would you do?
thanks again.
wizard124
Posts: 752
Joined: Mon Oct 29, 2012 9:27 pm
Your car is a: 1980 124 spider FI
Location: Sheridan, WY exSan Rafael, CA

Re: transmission rebuild question

Post by wizard124 »

Yes, now is the time.

Look here: http://fiatspider.com/f08/viewtopic.php?f=9&t=26031 Photos and tips to inspire you :)

So, once you have it apart, the question is what to look for? This is only my second transmission job but I offer these tips.
1) Get a new input shaft needle bearing (cheapest one in the transmission). Inspect the other bearings carefully, use a magnifier to look for scoring and pitting. Rotate them and ensure they spin smoothly. Some get pricey but when in doubt replace it.
2) Compare the thickness of each syncro and cone to the others using calipers or micrometer. You know which of your gears is trouble free so start with that one. You may not need to buy new for each gear.
3) Do the same for each gear fork. You will see wear on the sides of the fork. You suspect 3/4 fork is bad, worn or bent.
4) Look for chipped teeth on the gears and sliding sleeves (see photos in reference thread).

I'll repeat it again here for emphasis. Be very methodical in laying out the parts as you dis-assemble the transmission and take many digital photos for future reference. Clean and inspect the various sub-sets of the tranny one at a time; then lay them back in their rightful spot in the dis-assembly line. You DON'T want to take everything and dump them in the parts washer all at once.

A bench vise is a must.
vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: transmission rebuild question

Post by vandor »

If I open up a transmission, it gets at least all new synchro rings and springs (1-4 gears) and the shift forks get replaced if they show any wear.
Sounds like there may be a new input shaft (4th gear) in your future as well. Grinding gears wear their engagement teeth very quickly and they start jumping out of gear.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
timspider

Re: transmission rebuild question

Post by timspider »

sounds like I'll be throwing some stuff in my auto ricambi cart soon.
Resigning myself to this being a winter project.
Thanks for the help
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SLOSpider
Posts: 1140
Joined: Wed Mar 03, 2010 2:10 am
Your car is a: 1973 124 Spider 2.0FI
Location: Lompoc, Ca USA

Re: transmission rebuild question

Post by SLOSpider »

wizard124 wrote:).

I'll repeat it again here for emphasis. Be very methodical in laying out the parts as you dis-assemble the transmission and take many digital photos for future reference. Clean and inspect the various sub-sets of the tranny one at a time; then lay them back in their rightful spot in the dis-assembly line. You DON'T want to take everything and dump them in the parts washer all at once.

A bench vise is a must.
Explain methodical to me? Bench vise?

Image
1975 124 Spider
1976 Mazda Cosmo http://www.mazdacosmo.com
1989 Chevy k5 Blazer
1967 GT Mustang Fastback
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