T56 clunk noise

**Barnesgn231** · 03-19-2018, 04:00 PM

Been having a slight clunk noise whenever I shift from 1st-2nd. I thought it might be a bad bushing so tonight I lifted it up on all fours and did a drive line test. The torque arm bushing does move a little, the trans bush is solid. I noticed that the slip yoke has some play going into the transmission, the u joint is solid and driveshaft is also good. T56 output seal is not leaking. Do the slip yoke wear on these cars or is it something in the transmission. I did grab the yoke and move it a small amount, should it have any play? Are any bearings toward the rear that go bad often, I've had the clunking since I purchased the car last year does not seem to be getting worse.

TIA.

***SMWS6TA*** · 03-20-2018, 08:27 AM

There should be no play at any u joints.

It could also be in the rear diff. You would have to disconnect the drive shaft and try to move the pinon yoke. There is a "little" play like less than 1/16 to 1/8" any more than that and yo might want to check out the diff.

All bearings go bad at some point. Since you've been driving it for a year and no change I would just monitor it. You might want to tighten the torque arm bolts some, if loose they can make noise.

Do you have headers? Some times they can slap the floor if they are close.

**Barnesgn231** · 03-20-2018, 11:53 AM

Appreciate it, I am almost positive it is in the rear of the tail section of the trans and not in the diff. If I need too I'll drop the driveshaft and pull out the slip yoke, and grab the output shaft. Check for play in it. My gut tells me loose bearing along the output shaft.

***SMWS6TA*** · 03-20-2018, 12:02 PM

I grenaded mine last summer and had it sent to Tick. Ended up doing a Lvl 3 build.

**Barnesgn231** · 03-20-2018, 04:23 PM

Your right it's the diff. My dad helped me listen to the driveline noise. If you rotate the rear passenger tire you can here the slop in the ring gear.

My dad wanted me to ask : With the car in first gear if you spin the rear tires why won't the driveshaft spin?

The previous owner had the rear end rebuilt last year, my plan is to take it back to the shop see what they say warranty wise then go from there.

***SMWS6TA*** · 03-21-2018, 11:48 AM

limited slip traction.

Most likely the diff clutch packs have worn out from someone doing too many burn outs

**Barnesgn231** · 03-21-2018, 05:05 PM

Sadly not 1 burn out from me. Got some decisions to make. Just tried to call Hawks motor sports to check on a 8.8 hybrid......one of their warehouses burned down!

***SMWS6TA*** · 03-22-2018, 06:52 AM

Saw that, hope everyone is ok.

I built my 8.8 before vendors got into the game. Hawks has a nice setup and Moser does as well. There are a couple of guys on Fb that make them too. One in OK and another in AL. Both seem to have a good rep on quality.

They are all based on how mine is setup. A guy on LS1tech came up with a kit and procedure in order to use the torque arm our cars use. The hardest part is the welding. You have to use a specific type of rod material and control pre/post heat for welding to get the Hiltsy Kit to bond with the center section.

When selecting a rear....

9" - considered heavy duty, great for track use, the 3rd member allows for quick gear changes or repairs at the track. Neg - a higher parasitic loss on hp from drive train.

8.8 - this was the workhorse of race cars for decades till the 9" came out. Tough as hell and are found in a ton of vehicles. The GM 12 bolt is practically a copy of the 8.8. Less parasitic drag then the 9" but a little more then the POS GM 10bolt that's in f bodies. Neg - does not have the 3rd member like in the 9", so if you need to change gears or repair a diff at the track it takes much longer.