Friday, December 21, 2007

Snatching the Transmission Back

Well, I'm back to square one again on the tranny. Rennsport Systems kept my transmission for over two months and didn't work on it. I asked the good folks over at about the situation and most people suggested that I was waiting far too long and paying far too much for what I was doing. Two folks highly recommended I go out to the Rennsport shop without calling ahead of time and just take the transmission back, just to be sure they didn't start working on it as I drove over.

So that's what I did. Jeff at the shop was gracious enough to give me back the transmission (and the extra-parts tranny) without any questions. They seemed completely stressed out due to the extreme backlog of work, anyway.

I'm in the process of trying to buy a rebuilt tranny from one of the 914world folks, so I hope that pans out. My other option is to have "Dr. Evil" from 914world rebuild a transmission for me for $1500.

My gut feel, not based on any fact, is that a different transmission won't have the same resonant problem as this one does; however, it may come with its own problems. Stay tuned as the saga continues...


Gizmo said...

Wow. That is too bad, Tim. I've been waiting to see what your real world range to 50% DOD is. In the meantime I've been wondering what you are doing to exercise your battery pack. Isn't sitting hard on them, even if you keep a float charge on them?

I hope you get things figured out soon.


TimK said...

Hi David, I'm interested in my 50% DOD range is too :) Have you been getting numbers from Ross Cunniff and Onei57 (see blog links at right)? They completed their 914AC kits recently too.

As far as the batteries go, I've heard that keeping them sitting with a float charge is just fine for long periods of time. It's the cycling that causes reactions with the plates and degradation. Since I got fed up with things a month ago, I've actually just let the pack sit at full charge for two months, which is probably a bad idea, but the float voltage has only dropped from 154V down to 150V which is still mostly charged. I'm going to charge it up again this weekend.

Cheers, Tim

Roger Daisley said...

Tim: From following the vibration saga, I'm not 100 percent convinced it's the tranny ... maybe it is, maybe it isn't. It seems a shame to wait so long and possibly waste a ton of money rebuilding a transmission that is really OK.

Here's a suggestion and something that I would try, if I were in your situation. It's worth a try.

Drain all the oil out of the tranny and flush out with kerosene or very light oil. (Like WD40)

Then take the tranny to a good mechanic and have him "feel" how the mainshaft and gears turn. With very little oil in the tranny, a good mechanic should be able to tell of there are flat bearings or unusual looseness in the gearbox.

If it feels suspicious, then overhaul it, but you may find it feels tight and turns quite nicely. If you find the latter, then turn your attention to your original problem ... the coupler or possibly an unbalanced flywheel.

Just an idea that doesn't cost much to try and might save you a ton of money.

I's hate for you to spend $1500+ and be right back where you started.

Gizmo said...


I don't know if you saw this on the EVDL so here is a quote from John Mogelnicki....

3) If the motor shaft and trans input shaft are not 100% dead on center, (due to a homemade adaptor plate or one that's just slightly off center due to old tooling) the clutchplate will act as a flexplate to absorb some of the off angle drive... otherwise you'll be vibrating the car until things
fall apart.

----end quote----

I didn't know if this was some how related to your vibration issue or not. Maybe something isn't exactly lined up. Is there any play in the adapter plate with the bolts loose?


TimK said...

Hi Roger and David,

Thanks for the suggestions. I'm ordering a newly rebuilt transmission for $850 and am going to try that out. I have a reasonably good gut feel that it's a bent input shaft since putting on a different transmission (albeit a "bad" one) with a straighter input shaft makes the problem go away.

Greg Robbins, who is selling me the transmission, is willing to give me a refund if the problem persists, so I don't have much to lose.

At this point, I'm willing to toss a bit of money around to get the EV going and work on the transmission later, or perhaps sell it for parts and work on more EV-related circuits.

Thanks again for your comments and support, it definitely keeps me going. I hope your Christmas went well and have a Happy New Year!


onei57 said...

Tim if you get a chance before installing get some high temp cast aluminium paint (I used Duplicolor brand from advanced auto parts). I stood mine up on a tire rim to paint, looks much better! I saw the trans listed a few weeks ago that you are getting. Sounds like a good fix. Matt