85MikeTPI

iTrader: (9)

http://www.eecis.udel.edu/~davis/z28...SR_2pc_Hybrid/

Just finished up the second variant of the SSR hybrid. This one has a Fbody tailhousing bored out for the SSR/TH400 slip-yoke bushing and seal. Other than the 2pc counter-shaft/extension-shaft, the lower 4 gears are the same strength as the 1000hp version. The donor was a std C5 MM6 unit with a bad 3rd gear synchro. It was replaced and billet keys on 3-4, and 5-6 (stock solid 1-2 keys come std on late-model triple-cone units) along with a full set of bronze fork pads. (steel 3-4 fork also std on late-model triple-cone units)

Will continue to collect parts and build/prove the other 2 versions (viper-mod tailhousing with modified TH400 slip-yoke; and a 1pc countershaft conversion on a std C5 MM6 doner using a SSR tailhousing)

Stay tuned...

Mike454SS

iTrader: (4)

So my 06 ZO6 unit has solid keys already? I haven't opened it up yet.

85MikeTPI

iTrader: (9)

It will have solid (powdered metal) 1-2 synchro keys and steel 3-4 fork..

Mike454SS

iTrader: (4)

I bet the powdered metal keys are stronger than billet.

Are the keys compatible with all the synchro's or are they unique to each one?

Mike454SS

iTrader: (4)

Mine didn't, no big deal, especially since the seal is cheap, but its a need to buy item if going with the SSR tail housing. Maybe GM changed things, or maybe I just got unlucky and they forgot to pop the seal into mine.

85MikeTPI

iTrader: (9)

Oops, sorry about that. I just double-checked and saw that mine came with the bushing and the 1pc bearing, but not the seal... I remembered 2 things it came with that I bought separate and didn't need, but it wasn't the seal, sorry.

I'm pretty sure a TH400 seal would work, but I haven't had time to check/verify. I got my last batch of seals from http://www.autopartstomorrow.com/ (ACD 23049496)

Mike454SS

iTrader: (4)

Yeah it's no big deal. It DOES have the bushing and bearing in it.

gsd2000

iTrader: (1)

Great write up mike, very informative

BlazinT/A

iTrader: (10)

so has anyone tested these out yet? im still curious how they hold up.

95wagon

Somewhat on topic,

What parts would I need to move up 6th gear in the SSR trans from .57 to something in the .6's
Looks like I would need m28- m29 5-6 netting a .8 and .62.
But that would result in losing the new style syncros , correct?

Anyone know if the 2000 Cobra R (same ratios) used a different 5-6 syncro?

While I would like the get 6th higher, I don't want to lose the newer syncros.
Thanks, Gerry

85MikeTPI

iTrader: (9)

You would lose the double synchro on 5/6, but it could be retained on the 1-4. You'd have to swap in a single-cone 5/6 extension shaft and driven cluster from a M28/M29 T56.

The cobra (ford) T56s used a fully splined mainshaft with separate 5 and 6 gears on the mainshaft.

You might just be better looking at adjusting your pinion gears to get the driveline ratio you need and sticking with a stock MM6 or MN12 gearset in the trans..

95wagon

Thanks for the info.

As you know ,
the M12 has the same 2,3,4,5,6 as my M10
and the MM6 has the 1.00, .74 .50 4,5,6

I am trying to tighten up the 5-6 spreads

Does anything aftermarket work?

Thanks again

85MikeTPI

iTrader: (9)

The aftermarket gears use a custom extension, thus a custom counter, all with their custom gears, so it's all or nothing. (And I'm not even sure if they offer anything custom for 5-6 since overdrive gears are not suitable for any performance application)

If you just want to tighten the spread, you could look into a MZ6 5/6. It would put you at a tighter .71 5th and .57 6th spread, but not the .8/.62 you mentioned. (The MZ6 is tough to find also.. Only offered in the '06-'07 Z51 vette option before switching over to the TR6060)

ls1450

I've been looking a building a trans with a viper shaft for a while. This sounds like a much better alternative.

I found a Z51 trans out of an 06 vette as a donor. But I don't know that I want the lower first few gears.

Is there any reason I shouldn't use the f body mm6 gears that I have other than they don't have the newer synchros?

85MikeTPI

iTrader: (9)

If you want the MM6 gearset and the modern synchros, you should look for a std C5 donor. If you want to use the f-body MM6 gears that you have, just do a viper conversion.

You really don't gain much mainshaft strength in the 32-spline over the 30-spline, the benefit is in the synchros.

The Z51 MZ6 is basically a MN12 with slightly lower 5th gear.

85MikeTPI

iTrader: (9)

I found GM part numbers for the SSR 1pc M10 countershaft (p/n 890599796) and updated the write-up.

http://www.eecis.udel.edu/~davis/z28..._Fbody_T56.pdf

Helps if anyone has a MN12 donor and wants to move to a stronger 1pc countershaft. You do have to change 1st gear along with the counter, but it's a standard MM6 1st gear.

In addition, I now have part numbers for both the MN12 and MM6 driven 1st gears from GM that already have the upgraded synchro lock machined in them. If you don't have access to a shop that can machine your donor's 1st gear, you can purchase them now if needed.

Hopefully these parts will stay available for the 10 years (2006->2016) that GM usually stocks replacement parts.

Mike454SS

iTrader: (4)

Mike, do you know of any sources other than thegearbox to buy the SSR main shaft, TUFP5211? They're showing it currently out of stock and unable to order

85MikeTPI

iTrader: (9)

I just ran into that shortage as well.. Check your GM sources for p/n 89059965, that should be the GM equivalent shaft for a few dollars more.

TDP

iTrader: (23)

I finished the 32-spline build a few weeks ago. Just been too busy to post about it. That modified mainshaft worked out great, btw. Remember I had the 2nd gear journal modified to accept the stock 1-2 snap ring. Other than that, I broke the CTS-V speedo gear trying to install it onto the splines. I even heated it up quite a bit with a heat gun. Ended up getting a stock 27-spline speedo gear milled out to 1.371in and it couldn't have been a better fit. I ended up using an 8in 1350 TH400 yoke. I got it cut down to 6.5in, and of course had the o.d. cut down to the proper size.

Mike454SS

iTrader: (4)

So you didn't use an SSR tail housing/bushing? You wouldn't need to resize the OD of the slipyoke if you went that route.