Gear whine good - so far (knock on simulated wood for me)

[cekim]

First heat cycle on the 3.73's (~10 minutes of polite stop-go-slow-fast) - quieter than the stock 3.55's so far... I set gear lash tigher on the new ones (~8-9 vs ~12-13) pinion depth and wear pattern on old and new were right in the middle and nice and deep (see lash above).

The 3.55's through the CHE parts added to the truck-like 3650's noise...

The trans in this car (the '05) was clearly not well loved by its prior owner and as the slap, whine, clunk and slop to prove it... My 06 is a lot quieter and firmer - I drive hard, but I am nice to the trans...

It was hard to hear much noise from the rear over the trans... Which given the CHE/poly parts has every reason to translate into the cabin... I could tell it was there at 60MPH, but again much quieter than the 3.55's on the same suspension parts...

Keep your fingers crossed for me.... Its cooling off now waiting for a second heat-cycle...

 

[94tbird]

:fingers crossed for you: hehe

 

[3V_V8]

Speaking of gear break in, my buddy got a set of 3.90s installed today and the installer told him just romp on it since if they are going to break they will break, plus the installer put in synthetic What is the proper way to do it since there seems to be confusion?

 

[cekim]

Speaking of gear break in, my buddy got a set of 3.90s installed today and the installer told him just romp on it since if they are going to break they will break, plus the installer put in synthetic What is the proper way to do it since there seems to be confusion?

Its generally not a matter of "if they are going to break" - its more a matter of getting the best possible mate between the gears (which means close, smooth and quiet)...

Heat cycling them 2-3 times (i.e. getting them up temp breifly and then letting them cool - then repeat) allows everything to expand and contract and get settled in while the lube and a small amoutn of material on the surfaces of the gears wear off...

Between the ring, pinion, pinion bearings, carrier bearings and axle shafts there are a lot of parts moving at odd angles relative to eachother... allowing them to expand and contract a couple/few times before you beat on them helps to ensure they settle into a good position...

 

[GIG4FUN]

I changed a lot of gears in the eighties and I NEVER told anyone about a break-in or a heat cycle...

I have only heard it in the forums... strange to me.

 

[US-1]

I changed a lot of gears in the eighties and I NEVER told anyone about a break-in or a heat cycle...

I have only heard it in the forums... strange to me.

Ditto.

 

[GIG4FUN]

oh..I never had a set fail or come back for noise either...

Well then do they get tore down and re-torqued? heck no... I work in a gear shop... I am STILL up in the air about this. When we grind/match them..well it's done.

 

[cekim]

I changed a lot of gears in the eighties and I NEVER told anyone about a break-in or a heat cycle...

I have only heard it in the forums... strange to me.

Changed some in the 80's, changed some in the 90's and changed some this weekend...

I was told a long time ago about that and have always had nice quiet rearends...

 

[GIG4FUN]

I changed a lot of gears in the eighties and I NEVER told anyone about a break-in or a heat cycle...

I have only heard it in the forums... strange to me.

Changed some in the 80's, changed some in the 90's and changed some this weekend...

I was told a long time ago about that and have always had nice quiet rearends...

haha..yeah I still do some every year since "the eighties" but now...well you got me paranoid. I always sent the customer off with nothing said... I think when I do mine.. (in the S197) I will be searching YOU and reading about this cycle heat thingy... LOL

 

[cekim]

I changed a lot of gears in the eighties and I NEVER told anyone about a break-in or a heat cycle...

I have only heard it in the forums... strange to me.

Changed some in the 80's, changed some in the 90's and changed some this weekend...

I was told a long time ago about that and have always had nice quiet rearends...

haha..yeah I still do some every year since "the eighties" but now...well you got me parinoid. I always sent the customer off with nothing said... I think when I do mine.. (in the S197) I will be searching YOU and reading about htis cycle heat thingy... LOL

Just tell him its magic pixie dust...

All I can say is:
a. see above - the dust seems to work - so I sprinkle liberally
b. when I look at thesurface of the gears and bearing races with just a 100 or so miles on them and the gears and races when they first go in - clearly those surfaces are changing eachother when they first meet... Those are big hunks of metal that expand and contract significantly with just mild heat...

So, is it best to pound on them during that period or drive them like granny? Well I guess we have to add that to the break-in mythology thread...

p.s. I have been a believer in the break-it-in-like-you-stole-it school for engines for a while - so I can be swayed by data...

 

[ZmanM3]

I like the brake it in like you stold it because it just seems like more fun. Good luck with the new gears!

 

[GIG4FUN]

Funny... Last night after I went to bed... I laid there and thought... "Geeez, I could have at least said something about how nice it was that you got them in, good job, sweet, or something postitive!" I almost got back up to post it up!

So here I am today: Congratulations on that gear install!

 

[VSOP]

So did the rear end blow up yet.. If not I'll knock on some wood for you now..

 

[94tbird]

So did the rear end blow up yet.. If not I'll knock on some wood for you now..

jeez hahaha

 

[VSOP]

That Mild compared to some of the crap I have given Cekim..

 

[94tbird]

thats is true it was pretty tame. your losing your edge man lol

 

[VSOP]

Just waming up

 

[94tbird]

hahahahahahaha

 

[VSOP]

Ok warmed up.. So where is Cekim with the update.. Did he breakdown on the side of the road waiting for the Ford Tow service...?

 

[94tbird]

ouch dont say that lol