Manual Trans. Thud when shifting

[mustang_guy]

I dont know how you couldnt feel or hear it. This has been an issue since the trans was released. My '12 was the same way. Never hurt anything and it never got worse.

Pretty easily. It didnt thud, at least 10 of my buddies s197 coyotes dont either. Some of them are pushing 550-750whp. No thuds. i know of some others im not actual friends with, thuds. The majority are very happy with the trans. The minorities speak the loudest. Ive been driving sticks for 25+ years. Its a decent trans, while not the best ever stick ive driven its not a pile of crap either.

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[PRG3k]

The thud has little to do with the Torsen lsd or performance packs. Both of my Eco's had it. I think it's been pretty well explained at this point as to what it is.


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[EXP Jawa]

The thing to keep in mind is that the Torsen cars are the only ones that come with 3.73:1 gears. The higher numeric the ratio, the more they'll amplify any axle system lash when checking it at the prop shaft. So, IMHO, the PP cars are more likely to accentuate transmission clunks and lash issues. But the correlation is to the axle ratio, not the diff.

 

[Darkhelmet22]

The thing to keep in mind is that the Torsen cars are the only ones that come with 3.73:1 gears. The higher numeric the ratio, the more they'll amplify any axle system lash when checking it at the prop shaft. So, IMHO, the PP cars are more likely to accentuate transmission clunks and lash issues. But the correlation is to the axle ratio, not the diff.

Didn't realize that the 15s didn't have an option for 3.73 in the standard LSD. My 13 had 3.73s and didn't have the Torsen diff.

 

[gsxr1300]

While my trans what out getting a clutch, I noticed my clunking is play in the dif. can rotate is back and forth about and it clunks.

 

[EXP Jawa]

There's always going to be some bash in the axle. Keep in mind that it isn't the diff itself - or, not entirely the diff - that contributes to it. Between the pinion shaft and the wheels, you've got the ring & pinion mesh, the differential gearing, the axle shaft to diff gear fit, multiple CV joints, and a spline to hub fit, all of which require some small about of clearance in order to be assembled and function properly. All of those contributors add up - when you hold the wheels from turning and apply torque to the pinion, you'll get around 4 degrees of rotation from the combined lash. Again, it'll higher for numerically higher ratios, because the gearing acts as a multiplier for lash as well as for torque. If you had 1 degree of lash in the differential and axle shafts, that will translate into 3.3 degrees with a 3.31:1 gearset (above which you'd then add the lash in the R&P itself as well), but if you 3.73:1 gears, you'd have 3.7 degrees of backlash before adding the gearset lash in. So, the ratio factor isn't huge, but it is noticeable. And, of course, anytime that there is lash, there will be a clunk. It's just the mechanics of it. The big question is: how big of a clunk, and how audible is it inside the car? But again, if something is going on inside the transmission, anything out at the axle with accentuate it.

 

[gsxr1300]

At least now I know where its coming from, I can rock the driveshaft back and forth and all the play is the back end of the shaft, I have no movement when trying to turn the axles.
Maybe a carbon fiber drive shaft will transfer it less into the cabin, the sound while driving sounds like its the transmission.

 

[mustang_guy]

wrx and sti have rear diff clunk when raced. The fix for it was either solid billet bushings or poly. Still weird most don't clunk on s550 but some do. I wonder if some just got a loser tolerance during assembly then others on accident.

 

[EXP Jawa]

Different manufacturers have different levels of what is considered acceptable. You get into AWD systems, and there is another level of complexity of what's involved with driveline lash. But if the clunk was fixed by bushings, then it wasn't truly driveline lash, its more likely to be axle carrier or subframe movement, a different issue entirely.

 

[Cascadia_302]

The thing to keep in mind is that the Torsen cars are the only ones that come with 3.73:1 gears. The higher numeric the ratio, the more they'll amplify any axle system lash when checking it at the prop shaft. So, IMHO, the PP cars are more likely to accentuate transmission clunks and lash issues. But the correlation is to the axle ratio, not the diff.

FWIW my experience driving the 3.31 ratio manual did not present the same so called clunk noise or feel the 3.73 ratio PP car produced. I would have had zero issues living with the clunk from the PP car, it just comes with the equipement package and set-up you are using.
I ended up buying the 3.31 car which was for reasons irrelevent to this discussion but I do mainly agree with your assessment on the topic.

 

[redline727]

Someone should create a poll to see. Have 4 options, thud heard with 3.73, thud heard 3.55, thud heard 3.31, and no thud heard at all with MT82. I don't think it's an issue but there are plenty of people on here that feel differently. Maybe for those people they can make better sense of it if all if the people that notice it have 3.73's ?

 

[Darkhelmet22]

Soooo..... I installed my MGW race spec last night and the thud in 3rd is almost unavoidable now. I could usually get the clutch and shift timing down to not make the noise but with the MGW it is proving to be very difficult. The damn spring they put in for the 2-3 shift is stout. I wont miss third ever again though lol.

 

[Dawg]

Google MT82 problems. Lots of entertaining reading.

 

[mustang_guy]

Google MT82 problems. Lots of entertaining reading.

Google gt500 tremec issues, youll find even more. no trans is without some flaws.

 

[Genxer]

Google MT82 problems. Lots of entertaining reading.

I haven't seen much regarding the S550. Most of the real problems I've read about is with 11-14, and most of that the 11.

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