transmission questioni

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Don
Posts: 46
Joined: March 24th, 2007, 3:40 pm

transmission questioni

Post by Don »

Just finished my first race of the season. Saturday sessions were fine but on Sunday during the last session the transmission started copming out of 3rd and 4th gear on acceleration. I do not have any history on the tranny. First sign of an issue was hard to shift into 3rd from standing still at pre gird (shift into 4th then ok to sift into 3rd). During the race shifting was ok but as I said on acceleration I could feel the gearshit sliding back out of gear. Finished the race by holding it in 4th. I assume that this is not a simple issue and will require taking the transmission apart. Does anyone have any suggestions on whta to look for inside the transmission?

thanks, don
billinstuart
Posts: 201
Joined: July 17th, 2006, 8:53 pm

Re: transmission questioni

Post by billinstuart »

There's a fork and slider that engage 3rd and 4th. It was probably set up incorrectly, as it MUST be done in a jig or cutaway transmission. Holding it in gear wears the fork and slider, destroying them. The synchro's/balk rings engage the gears to speed them up/down to match the desired speed..they wear on the inside.

Look for damaged fork/slider, damaged sunchro, damaged teeth (not the gear teeth) on 4th where they engage the slider.
Caracal99
Posts: 41
Joined: June 25th, 2006, 1:45 pm

Re: transmission questioni

Post by Caracal99 »

If your Vee has a front motor mount, check that to insure that it is not broken or otherwise loose. If the engine/transmission are moving under acceleration, you possibly may be causing it to come out of gear...

Paul
Dietmar
Site Admin
Posts: 650
Joined: June 24th, 2006, 11:56 am

Re: transmission questioni

Post by Dietmar »

As already stated, I would check the shift fork position on the selector shaft. They do come loose.
Just had one here a few weeks ago with the same issue and the fix was an adjustment ( and yes, it has to come apart)

Hope this helps

Dietmar
http://www.quixoteracing.com
brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: transmission questioni

Post by brian »

X2 Dietmar, it's time for a tear down if you have already checked your linkage. Don't forget, that stuff wears out. Make sure your linkage is fully engaging the tranny. Pull back on the lever, then check the hockey stick to see if it wants to travel further. If it does, work on the linkage some more until the linkage moves the hockey stick it's full travel. Good luck.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
jpetillo
Posts: 759
Joined: August 26th, 2006, 2:54 pm

Re: transmission questioni

Post by jpetillo »

I did have a loose motor mount like Paul mentioned and it did this, but over bumps. Mine was actually a loose rear tranny mount. It's certainly easy to check for before doing a teardown, although our expert vee mechanic friends most-likely have it right. John
VDF1
Posts: 127
Joined: June 28th, 2006, 2:18 am

Re: transmission questioni

Post by VDF1 »

If your upper engine cover is supported at lower rear by the transmission tail you might check that. I once had 3rd/4th shifting problems and it wasn't the transmission at all, it was body interference that was stopping the linkage from fully engaging 4th gear. Leroy VDF-1 Coppedge
Life atrophies if it gets too far from risk
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