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Login to post Forums » Grassroots Motorsports » How to nurse a broken transmission (through a race)

April 21, 2011 10:02 p.m. Tyler H Dork

Our junkyard transmission for our Lemons car scratches third gear. It isn't in the budget to replace, without cheating, and I want to face the judgement with a clean conscious.

So we filled it with new honda gear oil. Drove it three miles and drained it. It came out looking like a mixture of motor oil and JB weld. Put redline heavy shockproof in it and got it hot yesterday. A rev-match double clutched downshift to third is fine. A second to third upshift still grinds.

If I ease it from second to third I get a soft griiiiind, thunk. If I shift it with some authority by revving it out in second, shifting to neutral, clutch out, clutch in and pushing it hard to third, no grind...just the thunk.

Which upshift method for the longest service life?
April 21, 2011 10:07 p.m. Toyman01 SuperDork

Don't shift? Or better yet, cheat. Everyone else does.
April 21, 2011 10:09 p.m. Tyler H Dork

We drive a Honda, which isn't cool enough to get away with cheatonium in Lemons. Not as bad as an E30, but still..
April 21, 2011 10:12 p.m. Toyman01 SuperDork

We run a Civic. A bottle of Crown for the judges does a good job of "getting away with it."
April 21, 2011 10:12 p.m. Javelin SuperDork

Skip 3 and use 2 and 4. You're not going to need the valves in the engine anyways.
April 21, 2011 10:32 p.m. Travis_K Dork

Just swap the transmission and dont say anything? From what i understand everyone else cheats, and why spend all that money to blow the transmission up an 20 minutes into the race? Or, bring a spare and swap it when the first one explodes?
April 21, 2011 11:09 p.m. Run_Away Reader

What kind of transmission? I think you could probably find another trans that needs work or a less-desirable geared model and swap what you need inside them. How much budget do you have left?
April 22, 2011 6:00 a.m. Tyler H Dork

We have a spare dx mystery transmission. Might be worth the time to try it out. What is this Crown you speak of? This is the South. Bribes come in Mason jars.
April 22, 2011 6:52 a.m. tuna55 SuperDork

Hey now, the cheating comments are a bit much.

Honestly, we changed ours in practice with another free spare, so n big deal there. Either find a free spare or don't use third. It might just be the syncro going, in that case, change the fluid enough times and stop using it.
April 22, 2011 6:57 a.m. RossD Dork

Can you buy a whole transmission and use only the syncro and the corresponding dollar amount in your budget?
April 22, 2011 7:37 a.m. KATYB Reader

it shouldnt be much to just buy a syncro for it.
April 22, 2011 7:55 a.m. Giant Purple Snorklewacker SuperDork

Yeah... just swap in another or fix the trans you have with the guts from a donor. The one you have will E36 M3 bits into the the other gears and eat itself. That will be fun for nobody. If your conscience won't allow it ahead of time - agree that it needs replacing as soon as you take it off the trailer. A working 3rd gear isn't a "performance enhancement" its a necessary part to have forward motion- especially at the low speeds a Lemons event runs. You cannot stay in 4th all day.
April 22, 2011 8:44 a.m. Maroon92 SuperDork

I drove a Ford Aspire without 4th for a year and a half. It was fine!
April 22, 2011 8:44 a.m. Maroon92 SuperDork

You can ask JB about that!
April 22, 2011 10:24 a.m. dculberson Reader

Giant Purple Snorklewacker wrote:

Yeah... just swap in another or fix the trans you have with the guts from a donor. The one you have will E36 M3 bits into the the other gears and eat itself. That will be fun for nobody. If your conscience won't allow it ahead of time - agree that it needs replacing as soon as you take it off the trailer. A working 3rd gear isn't a "performance enhancement" its a necessary part to have forward motion- especially at the low speeds a Lemons event runs. You cannot stay in 4th all day.

At NJMP, in the Civic wagovan, we used 3rd for precisely one turn on the course. All other turns and the straights were done in 4th.
April 22, 2011 1:36 p.m. Toyman01 SuperDork

CMP is a 2-3 track. Some of the turns are painful.
April 22, 2011 1:44 p.m. foxtrapper SuperDork

Rev match the upshift.
April 22, 2011 2:41 p.m. MCarp22 HalfDork

Double clutch the upshift?
April 22, 2011 5:36 p.m. KATYB Reader

he was saying even double clutching and rev matching doesnt help. the syncro is shot. replace the one syncro. and be happy.
April 22, 2011 7:40 p.m. triumph5 Dork

Hewlands don't have upshift or downshift synchros--no synchros at all; drive it right, and it lasts for many, many races--years, even. Learn to drive it better.

Rev matchting and double clutching not working? Technique/execution is wrong, or, there is something else wrong with the trans rattling around in it.

Final analysis, grinding equals making savings, which eats away at the other internals, so, go with the grind free technique--and hope for rain!
April 22, 2011 7:53 p.m. mr2peak Reader

Toyman01 wrote:

Don't shift? Or better yet, cheat. Everyone else does.

Really? That sucks.

However, I think this is a different situation. Run it till it dies, then replace it with the cheapest one you can find. But run it till it dies first, that's the point of lemons.
April 22, 2011 9:02 p.m. Curmudgeon SuperDork

Old transmissions with crunchy shifts will go a long ways. Believe me, if you have never run LeMons before a scrape going into 3rd will be the least of your worries. If you are really worried about the scrape/crunch/grind, run the cheapest oil you can find. Why?

A synchronizer depends on friction to make it work. 'Iffy' synchros will work worse with good oil because the synchro can't slow the mechanisms down to match the speeds. Honda boxes should run 20w50 motor oil. Run something a bit less slippery (cheap 90 wt or similar, stay away from Red Line etc) and see how that does.

My suggestion: run cheap sticky lube, bang shift the original box (shift it like you mean it, not like you are going grocery shopping) and bring a spare just in case.
April 22, 2011 9:20 p.m. fastmiata Reader

I dont get it. It is not like the trannies are marked or sealed. Just buy a used trannie and swap them out. Just dont advertise it. I am also sure that there is probably someone out there who can rebuild the trannie and make it last. ISC was my saviour with the RX3. We could swap out a trans in 90 min at the track and after paying Mike for a rebuild, I never had to use that experience again.
April 22, 2011 9:38 p.m. Tyler H Dork

We're just going to use it and bring a spare. This will be my fourth Lemons event, but first time with this car.

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