kanundrum

So I have my 05 tC w/Supercharger

It had a LSD and Clutch Installed in February of 08 (few months back) with a CC Stage 2. The past Month the car has been grinding from 1st to 2nd Above 4k RPM's only when I switch gears.

So I take it to the dealership and they say that the Synchros is bad and that I should replace it.

My question is, would installing a LSD cause the synchros to go bad if it was improperly installed, or is it just the months of abuse I put my car thru.

Keep in Mind the following


-Yes I do race my car (But I have not gone auto crossing or road racing within the few months period of me installing the LSD and the new clutch (was waiting on new suspension)

I drive somewhat aggressive on a day to day basis but nothing compared to auto crossing or track conditions.

kanundrum

Also btw the Clutch was properly broken in with no abuse for the first few thousand miles.

DTC08

i think it would be from u beating ur trans up....i mean if u shift into dump the clutch when in 1st and chirp in 2nd, dont expect ur trans to last very longto last very long...

kanundrum

I have dumped my clutch about 5 times within my 80k miles of my car. I don't drag race I autocross

kanundrum

bumpo

kanundrum

and does anyone make heavy duty synchros

bB384

The Synchros going bad would be a result of the abuse the Transmission has been put through.

tcengel

Most of the time, synchro issues are due to the wrong trans fluid or driving style. Do you downshift alot with out rev matching?

kanundrum

Most of the time no. I usually rev match pretty well

tcengel

What fluid you using?

kanundrum

Royal Purple 75w-90

tcengel

That is your problem for sure. Royal purple is too slick and does not include friction modifiers. Modern Synchros need friction modifiers in order to work. Switch out for BG Synchro, Redline MT-90 or penzoil Synchromesh (non-synthetic.) I bet it gets rid of some of the grinding right away!

kanundrum

Very odd since we have have Tons of people here using Royal Purple 75w-90. Ill look into it.

tcengel

Look at the label, I may be wrong. It will say if it's enhanced with friction modifiers or not. Same thing as redline, 75-90 gear oil is bad, MT-90 is good.

kanundrum

Hmm not sure I will check the label when I go home. I just know a LOT of people use it and trust it here.

tcengel

I learned all about Synchros with my 91 MR-2 turbo which you had to grind into almost every gear. Those Synchros were such garbage. After that, I had a 2002 WRX which again had a horrible transmission. The WRX guys actually create "cocktails" of different fluids in order to get the synchros to mesh.

g2autosports

Watching, I also have a SC with TRD clutch + clutchmasters flywheel, sometimes when down shifting into 3rd it grinds, but its not all the time, its random, but for sure it only does it when I go from 4th to 3rd. I'm also using Royal Purple, just recently changed.

equinox2355

I Have the same issue, i Have the LSD too, but mine has been getting worse since I first got the car. I noticed it but toyota never could replicate it. Its just been getting worse (even before my S/C was installed! Before my LSD was installed! I am going to have a transmission shop look at it.

g2autosports

BTW...I've had my transmission changed twice because of the same reason, so I'm actually on my 3rd transmission

equinox2355

Mine seems to do it when its cold but only when I am downshifting, if I am upshifting it usually is fine (just every once and a while). Most of the time it grinds is when I am down shifting from 4th to 3rd or from 3rd to 2nd. Hell I wish a company made a 6sp conversion for us like they did for the cobalt (SS) then I would gladly do that (since id have to replace parts anyway)