Reinstalling Rear Extension Transmission Case

This is the place to discuss restoration problems, post questions or projects-complete or partial.
Post Reply
AzzuraAzul1980

Reinstalling Rear Extension Transmission Case

Post by AzzuraAzul1980 »

Am in process of getting 5-speed gear box back together after re-build. Tried installing rear extension case to main transmission case but either one or both of the rear bearings (main shaft or lay shaft) seemed to bind as I torqued nuts/bolts to 18 ft-lb. With bolts untorqued, gear box rotated freely.

Haynes manual calls out just hammer-tapping rear case onto transmission case, which I did. Both bearings are tight press-fit into rear case. Is there a right/wrong orientation of rear bearings? Both Haynes and Fiat_Shop_Manual do not refer to anything special.

Appreciate your input.
User avatar
seabeelt
Patron 2019
Patron 2019
Posts: 1614
Joined: Tue Feb 19, 2008 4:22 pm
Your car is a: Fiat Spider - 1971 BS1
Location: Tiverton, RI

Re: Reinstalling Rear Extension Transmission Case

Post by seabeelt »

Might be tighter than when you took it apart due to wear, but should not bind. I would check to make sure the bearings are pressed in to the tranny "straight". Also did you put some tranny oil on the shafts as you slid them together. It does help some.
r/
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current
AzzuraAzul1980

Re: Reinstalling Rear Extension Transmission Case

Post by AzzuraAzul1980 »

Thanks.

The solution was to put the rear housing in the oven at 200 degF for 30 min and it slipped on perfectly. My crude calculations the dia. of holes in casing increased in the housing by 0.002" to 0.003" through heating which was more than enough to get the bearings to slip on.
vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: Reinstalling Rear Extension Transmission Case

Post by vandor »

Maybe there was a burr where the bearings slide into? I've rebuilt dozens of gearboxes and never had this problem, so it seems kind of strange, but hey, if it works now, all the better :-)
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
Post Reply