C Murda

iTrader: (24)

i bought my T56 from SixSpeedsInc (t56rebuilds.com) who are no longer in business that im aware of i think back in 2006. it was a Stage 5b build which was there best of the best package supposedly rated for 800+ft/lbs tq. it was been 100% reliable NEVER any issues with it until possibly now. i have maybe 40k miles of hard abuse on it 20k of which was through a detroit locker. ive been chasing an odd very harsh vibration that only comes at high speed in 5-6 gear and is mainly felt through the shifter handle itself and the transmission case itself. YES ive double checked EVERYTHING that it could possibly be from loose mounts or suspension or multiple pinion angles, new drive shafts, wheels out of balance etc... until i came across a thread about the 5-6 driven gear walking on the main shaft which cause a vibration exactly like mine.

anyways im wondering if anyone on here knows what type of parts are typically used in a strong high tq build like mine? do they simply use OEM gears? is the 5-6 driven gear an OEM part? or are they using aftermarket gears such as G force??? i dont recall them mentioning gforce internals being used but with a rating of 800+ ft lbs tq can that even be done of OEM gears? im wanting to know this so i can price out possibly a new 5-6 driven gear and main shaft or whatever shaft it is they seat on and i need to of course make sure its all compatible with everything else i currently have inside my transmission.

really wish sixspeedsinc was still in business this would be soo much easier!

stevieturbo

I have a similar box. It will be all OEM parts inside, just from different models.

My 5th and 6th appear to be from a Vette. I'd guess that's just down to fitment because of the larger diameter Viper mainshaft

Standard box would probably tolerate that torque for a very long time depending on application anyway as their OEM torque rating is obviously very conservative.

Nothing lasts forever though, you probably just need a fairly simple rebuild.

bmxer8699

iTrader: (16)

pm sent

dgcustomz

iTrader: (127)

Give Standard Transmission & Gear in Fort Worth Texas a call. They repair the mainshafts on the 5/6 driven journal to fix the issue. They do it for all the local shops. They are the ones that TDP takes the shafts to get repaired. If you just buy a stock mainshaft you'll just be in the same boat down the road. These shafts are machined a couple thousandths more so that it becomes a press fit.
Here is the contact info:
Standard Transmission & Gear
1000 N.E 29th Street
Fort Worth Texas 76106
817-625-7109

Ask for Fabian and tell him you're a member on Tech and he will hook you up.

C Murda

iTrader: (24)

thanks for the info. are these NEW shafts or shafts that have been plated??

AMP-D

The repair is a basic one. The journal for the pressed portion of the shaft has to be welded up and turned back down to a .0005 press fit for the 5-6 cluster gear. Its fine for shafts that do not have excessive wear in the splined portion of the shaft. Several years ago a fully splined shaft and matching 5-6 gear was developed and produced in a limited production. It was discontinued due to the lack of popularity but rumor is...... another company might bring it back to the market.

dgcustomz

iTrader: (127)

Usually you'll send your shaft in and they will machine down, build it up and machine it back down tighter than factory specs. There is a write up here by a member on his quest to figuring the vibration issues with his car. Mainshaft was worn on the 5/6 journal causing the 5/6 cluster to wobble and create the vibration. Sent it in to get it repaired and issue was fixed.