Countershaft bearing end play help!

Maintenance advice to keep your Spider in shape.
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SpiderJim

Countershaft bearing end play help!

Post by SpiderJim »

The wind picked up and knocked half my tranny parts all over when on a towel in the garage. If anyone has a pic or description of how the counter shaft bearing parts go back together or orientation would be appreciated. Particularly the counter shaft rear bearings. All the three manuals just say place the bearing with pics that are unusable. I installed the inner race per the manual then the roller bearing race then the spacer.

The strange thing is the entire bearing floats in and out of the case allowing the counter shaft to move axially even when the second end bearing is installed. Still does it with the end case on. I thought that the end case would hold it in or is it meant to float??? Tranny rebuilds would be a breeze If we had one manual that had clear pictures of bearing assembly and place in large detailed pics.

P.S. The best manual I have seen todate is the Clymers. Great description but unfortunately the many pics are black and white loosing key details that if photo clear would have resolved everything.
Last edited by SpiderJim on Fri May 27, 2011 8:09 pm, edited 2 times in total.
So Cal Mark

Re: Countershaft bearing end play help-Urgent

Post by So Cal Mark »

do you have the factory manual? The pics in it are pretty good
SpiderJim

Re: Countershaft bearing end play help-Urgent

Post by SpiderJim »

Yes, have three different ones including the factory manual. Unfortunately none show how the bearings orient. However, I think that I figured the axial end play on the counter shaft. If I attach the bell housing on the bench then it retains both the input and counter shaft bearings. I was testing with the tranny alone.... Phew!!!
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RoyBatty
Posts: 852
Joined: Sat Aug 28, 2010 11:44 pm
Your car is a: 1975 124 Spider - 1971 124 Sport Coupe
Location: Locust Grove, VA

Re: Countershaft bearing end play help-Urgent

Post by RoyBatty »

That rear bearing was assembled WRONG by a PO in my car.
It allowed the outer race to slide out the rear of the trans and hang up on the cross member.
Don't ask me what happened to the cover that should have retained it.
In any event, the nut on the rear of the counter shaft should retain the INNER race and the shape of the bearing assy then retains the OUTER race where it belongs.
Does that help any?
Here ya go. https://picasaweb.google.com/komepu/Des ... 8954008674
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SpiderJim

Re: Countershaft bearing end play help-Urgent

Post by SpiderJim »

Everyone a big thanks...... I finally figured the correct config of the bearings and assembled the tranny. I had a lot of axial play in the counter shaft until I placed the rear cover and the bellhousing together. Once assembled the end play was zero. I did not realize at the time that these two housings have machined shoulders that retain the bearings hence securing them in place. I'm no transmission expert but decent with a wrench for most things.

The tranny could be a very simple thing to work on if we only had really clear information in how it is assembled. I found two mistakes in the factory manual assembly drawings that have been re-produced by the after market suppliers in catalogs etc. I confirmed these errors with a tranny expert from one of them. Biggest issue is the multi- part bearings and how they orient together. No manuals show this, they just say install bearing and show a complete unit instead of a break down in an exploded view. Example... one manual says install spacer.. another says it is a spring washer and orient with the saucer side this way etc... That is confusing along with small pictures and so forth. A clear picture would resolve all of these issues.

If I was a 100% sure that I have built it correctly I would have taken detailed pictures of these critical areas but I'm not that positive at this point so did not want to mislead anyone. Regards removing yoke nut it was easy by just securing one of the three bolt arms in a vise and it just pops off. However, a long extension/ breaker bar is required because of the high torque.

Bellhousing and starter bolts are quite easy to remove or install with tranny in the car. I just loosened the engine mount lower nuts and removed the tranny support. This drops the tranny angle down allowing a bit more access to these bolts. Counter shaft nuts are removed by locking two gears up by placing in reverse and one forward gear per the manuals. Another manual say wedge the gears with a bit of wood.... yeah good luck on that one!

Errors in the shop manual and catalogs.

- Reverse idler gear shown in reverse
Input shaft... a confusing pic making one think that a spring washer inserts between the needle bearing and layshaft cavity. The spring washer is larger and fits at the end of the gear/bearing assembly and is retained by a circlip that is not shown in the drawings. The drawing shows two ends of the needle bearing that adds to the confusion.

My biggest beef is with the transmission tunnel clearance. If Fiat had just added 3/8" to the width of the tunnel at the bellhousing starter side and a little on the top of this section the tranny would just slide right in or out with ease. Instead it just jambs up even with the engine jacked rearward and down. Well its back in again and seems to be working smoothly after three times removed.

Why tree times out.
- I had the engine out for new seals and detailing and thought I would just replace synchros and clutch along with seals and forks. 200 miles and it begins to pop out of fourth gear. Turns out the new forks are thinner than the worn ones. Supplier said whoops I guess the mold gets worn.... Thanks mate! So purchased new forks again but this time old Fiat stock that was much better but more expensive. I also installed a new fourth gear layshaft assembly along with a new third gear that was also Fiat.

Everything fine when driving along at 50mph and then a big bang. lost first gear.... I could not get it in but otherwise the rest where great. Removed tranny again and found the 1st gear synchro had self destructed into small bits. So at this point I decided to just replace everything on the layshaft including new gears, bearings along with synchros and springs, synchro hubs sliders etc. I tracked down original Fiat old stock from several suppliers and paid premium. Also replaced reverse idler, slider and 5th/reverse fork.

Now all seems correct and happy. The tranny shifts smooth yet slightly tight from new parts. Moral is pay the bucks and get the original part not the crappy stuff. Even more if it is not broke don't touch it. Keeping fingers crossed and hope this helps someone. Cheers.......
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