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View Full Version : Tailshaft Change 1980 RX-7



tdw6974
06-14-2005, 09:38 AM
Lost 3rd gear in our tranny at The "Ledges" so I have a replacement but needs a tailshaft housing Change. Is it pretty straight forward to swap the tailshaft housing? Probably should dig out the old haynes Manual. Not sure if we have bad snycro or bent a fork. certainly was toasty warm in Ohio for the weekend!

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Tom Weaver: Logistics & Technical Support Manager IE truck driver for 1980 RX-7 ITA #63
"Hemi Haulin' Rotary" Bill Weaver Driver- 2004 NYSRRC John Chave Award

Chris Taylor
06-14-2005, 12:19 PM
Did you just lose 3rd gear? If it was a fork, both gears on that fork (and possibly the ones following it) would be "locked" out. If 3rd gear itself doesn't work, you've got bigger (read: internal) problems.

For your sake I hope it's a fork... much easier to change/fix than internals. http://ITForum.ImprovedTouring.com/wink.gif

ddewhurst
06-15-2005, 07:43 AM
Tom, tell us more about the transmission failure. What was the issue before you take it apart ? I know a driver who had the lever stick between 3rd & 4th. Wouldn't move any place/direction.

Drivers DO make errors http://ITForum.ImprovedTouring.com/redface.gif (crew _ _ _ _ up.)
David

L.Lamb
06-15-2005, 03:21 PM
Is this a 80 model trany? If so, pitch it. The 79 and 80 and first few 81 five speeds had a unfixable problem. Mazda corrected it in the late 81 and later trannys. The third gear slider would move far enough to uncover the dogs and they would pop up and lock you in third gear. Then the forks, synchros ect. would melt down.

tdw6974
06-15-2005, 10:14 PM
[quote]Originally posted by ddewhurst:
[B]Tom, tell us more about the transmission failure. What was the issue before you take it apart ? I know a driver who had the lever stick between 3rd & 4th. Wouldn't move any place/direction.

Seems that under race conditions sticks/stuck in 4th gear under load. would work up through gears at low speeds. Fluid did show brass shavings in bottom of drain pan.

Chris Taylor
06-16-2005, 12:22 AM
Originally posted by L.Lamb:
Is this a 80 model trany? If so, pitch it.And don't forget to cut a notch at the back of the lever opening so it doesn't take you 6 hours to R&R the later transmission in the earlier car! http://ITForum.ImprovedTouring.com/eek.gif

ddewhurst
06-16-2005, 08:06 AM
Tom, sounds like a (or more) Syncro is going/gone & maybe the 4th gear Synchro is cracked. If the Synchro is cracked once or more you will no longer have a one piece 360* Synchro. Funny $hit happens with those conditions.

The deal I was talking about in the previous post there was driver error while shifting from 3rd to 4th the driver hit reverse & with no Synchro in reverse the gear teeth were ground & jamed with stuck shift lever. Very fixable with an air grinder & small tool.

Suprising more people don't jump in with THEIR past transmission issues.

David

Boswoj
06-16-2005, 06:59 PM
I just got done pulling a '79 tranny that has this exact problem. Transmission had increasing vibration over the course of the week-end, then jammed in 3rd with not other options. Explaination was exactly as L.Lamb described. Lengthened shit lever opening, put in a "newer" old transmission, topped off with good synthetic gear oil and back to the track.

jake7140
06-17-2005, 12:19 AM
Originally posted by Chris Taylor:
..... If it was a fork, both gears on that fork (and possibly the ones following it) would be "locked" out. If 3rd gear itself doesn't work, you've got bigger (read: internal) problems.......


Chris,
Going from 3rd to 4th last year, lever got stuck in the 4th position, but with no power being transmitted. Eventually unjammed the stick, and ended up with 1 & 2 working, but not able to move the lever any further to the right. I think I may have just pulled the lever to the right when pulling it down into 4th.

Might this be an 'easily fixed' fork issue? I still have the trans, figuring it could be a good learning experience since I've never opened a transmission. Would be neat if it was also fixable/usable too though.

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Steve
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