GB: 5th gear plate mod

[ftjandra]

A few people have been asking me about the 5th gear plate mod. I am going to make a small batch of them next month. Pricing will be the same as last time $350 for the plate (going down by $15 for every 10 people) and $150 for the case machining, plus shipping. I will need a $150 deposit by the end of the month. If you want your case machined, I'll need it by 11/10/2014. I have detailed instructions if you want to machine the case yourself/locally. Plan is to have everything finished and shipped back before the end of November.

Details:
- Group buy will close October 31, 2014.
- $150 deposit required by October 31, 2014. Not refundable after October 31, 2014.
- If you want me to machine the center case and install the plate, I must have it by November 10, 2014 otherwise the price to machine the case will go up to $165.
- I will keep track of all the center cases. You will get the same one back that you sent me, in the same packaging. If you send it to me wrapped in brown paper, then that's how you'll get it back...
- I want clean cases. Spend a few dollars on a can of brake cleaner, purple superclean, etc. I'll charge $25 if you send me a dirty case.
- I expect to ship bare plates within 2-3 weeks and complete cases within 4 weeks at which point final payment will be due. I will send you a PM with your shipping costs at that time.
- I will accept money orders or paypal. Paypal address is same as my email: ferdi [at] ferdster (dot) com. Email/PM me if you want to send me a money order.

When taking apart your case, keep the bearing races matched to the shafts (ignore if you're replacing them).

I recommend that you check the endplay/preload on the shafts/diff. I have seen a few that have been out of spec, probably from the outer bearing races spinning and wearing down the aluminum.

Here are a few pics from previous runs:









Thanks,
--Ferdi

[ftjandra]

Bump.

--Ferdi

[jjk1224]

PM sent!


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[KAinjection]

Just to let Ferdi and the potential buyers know ahead of time, you really should check your bearing preload or have a transmission shop do it when installing this modified rear case.

I measured both my input and output shaft on mine and the input shaft requires a .004" shim and the output shaft requires a .035" shim. Neither of which is available from Mazda so I may have to not use a shim on the input and double up 2 shims for the output.

I didnt get around to checking the differential just yet.

[ftjandra]

I'd double-check the measurements by installing the bearing races without any shims and bolting the case together. Then just measure the endplay. That's how I've always done it.

I have never seen a case with measurements like yours.

If I remember correctly, this is a frankenstein case, right? The case halves are not 'matched'? A few people have done that, but who knows if they measured anything even though I make a point that it should always be done.

--Ferdi

[KAinjection]

I never thought about that to be honest, I should try that method and see if the measurements are different. It seems the only point of the shims is to have zero endplay in the shafts and to slightly preload the differential bearings.

Yes this case is a real Frankenstein, a plate modded rear KL case I bought from another member and the MZR front case, and I also replaced all the bearings/races with brand new OEM ones. Think this has anything to do with it?

Any suggestions for me? considering one shaft needs a shim smaller than is available and the other needs something larger than is available? I could double the shims up on one of them even though the service manual says not to do that.

[ftjandra]

Older g-series boxes used two shims with one of them being a .0276" diaphragm shim (it's slightly cone shaped and acts like a spring). In the later years Mazda switched to a single flat shim. I am assuming when this change happened they machined the bearing bores less deep. So the case that you got might be from an early g-series and actually calls for two shims.

You sure the bearings are seated all the way? I've never seen clearances that were so different from each other.

--Ferdi

[KAinjection]

I wondered what those cone style shims I pulled out out of the old cases were. This all makes sense now, thats why they could get away with a bearing clearance that large.

So since you asked if the bearings were seated all the way, I thought about when I pressed the bearings on and there was one I wasnt sure of when I did it. I still have a second early G box sitting on the floor and pulled the shafts out to inspect the bearing and compare to mine. Sure enough I found the small bearing on the input shaft was not not touching the gear like the untouched shaft from the other case. I could actually run a .035" feeler gauge under it, so I put that thing in the press real quick and it moved slightly more and sat down on the gear.

I threw it back in the case and rechecked the endplay. I went from .004" to now being .027" and also realized I was reading the gauge wrong thinking for some reason each mark was .002" instead of .001", so that would make the other shaft .033" instead of .036"

Those numbers sound a lot better? lol

[ftjandra]

If you could fit .035" feeler gauge before, why did the endplay only go up by .023"?

Just make sure that all your bearings are seated all the way.

In either case, it seems your problem has been solved .

--Ferdi

[KAinjection]

I have no idea, but I couldn't get it to go anymore than that and it's all the way down on the gear now. Thanks for the help either way.

[KAinjection]

Ferdi, IDK if your on any of the Mazda 3 forums but maybe they would be interested in this mod as well. Since I made my hybrid transmission I have a Mazda 3 rear case sitting here if anybody wants to use it for the plate mod. Just pay for shipping.

[ftjandra]

Ferdi, IDK if your on any of the Mazda 3 forums but maybe they would be interested in this mod as well. Since I made my hybrid transmission I have a Mazda 3 rear case sitting here if anybody wants to use it for the plate mod. Just pay for shipping.

Good to know for the future. So, the Mazda3 uses a g-series just with a different bellhousing?

--Ferdi

[KAinjection]

Yes it's just like our G-series except with some minor differences. It looks to me like the rear case can be machined in the same way since the bearing area is exactly the same. I can get you comparison pics up tonight if you want.

[ftjandra]

Yes it's just like our G-series except with some minor differences. It looks to me like the rear case can be machined in the same way since the bearing area is exactly the same. I can get you comparison pics up tonight if you want.

Sure, some comparison pics would be great. So the end cases are not exactly the same. Every now and then someone asks me if I have a spare case I could install the plate in, so I might take yours.

--Ferdi

[KAinjection]