98CayenneT/A

Well here is what I got going on.....last spring I pulled my 4l60e out and had it rebuilt. Put the tranny and converter (yank 3600) back in with zero issues.
My issue is now whenever it shifts into 3rd there is a clunk and every once in a while there will be a shutter. 1st-2nd is perfect, 3rd-4th is perfect and at wot everything is perfect. It's only during normal driving that I get a 2-3 only clunk. I have put about 3,000 mi. on the rebuild and about 15 track passes.
Anything to point me in the right direction would be much appreciated.

Car specs:
1998 trans am
4l60e/shift kit /yank 3600
10 bolt with 3.73's
steel drive shaft
Poly motor mounts
Poly tranny mount

jblankenship

iTrader: (5)

torque arm relocated?

98CayenneT/A

No, suspension is stock. Shifting into 3rd gear at part throttle is the only time it happens and it happens every 2nd-3rd shift but not at wot. If I had to guess it's rebuild related but I know nothing about auto internals really or if there is anything that could possibly cause this issue in 3rd only

jblankenship

iTrader: (5)

I would look closely at your torque arm

98CayenneT/A

Ok, I will definitely look at it. Maybe I will just get a better torque arm and get it off the tail shaft also. Thanks for the reply

98CayenneT/A

I guess if I had to describe the clunk it would be like a bad u-joint

PBA

When you had it built, did the builder add the Sonnax Heavy Duty 2-3 shift valve? This will give the 2-3 clunk a lot of the times.

98CayenneT/A

Yes he did, would you consider that to be a "problem" ?

mjs1012

iTrader: (36)

My FLT trans has been doing this since I got it over 3 years ago and I havent had any issues with it. It annoyed me at first but I guess that's just the nature of the beast. I've relocated my torque arm, put in a new trans mount and have a new driveshaft so its the trans doing it. At WOT its fine tho.

mrvedit

It will only "clunk" when you have it in [D3] and the trans shifts from 3rd to 2nd as you slow down. No, it is not a problem.
For drag racing, this valve reduces strain on the relatively weak forward clutch when you have the shifter in [D3]. Without this valve you should drag race in [D4]/[OD] (this has been detailed in many threads.) Therefore, this valve is a useful addition.

98CayenneT/A

Alright, figured I would update this in case someone down the line has the same issue.
Got it figured out today. Originally I didn't think it was u joints because I checked them. Made about 20 track passes this season and developed a vibration with a beat on the highway so I pulled the driveshaft out, u joints still seemed fine. Brought it in and had the driveshaft balanced and new u joints pressed in anyways. Took it for a drive and my 3rd gear shutter and clunk is gone.
Seems the 1:1 gear can really point **** out when something is wrong
Thanks again for the advice and input guys

69CamaroLS3

I have a 69 camaro LS3 480 with a 4l70e trans. I too have this clunk into 3rd gear only while driving normal. Shifts great otherwise and cannot figure out what the issue is. any Ideas?

69CamaroLS3

I have the same issue!! this is my first time on this forum and would love some guidance.

tayto

Did you read the OP's final post? I believe he found the solution...

69CamaroLS3

Hey Guys,

Just a quick update. I went ahead and took the beast (my Camaro) in to Drivelines Inc in Mission viejo and had them pull out the drveshaft. Upon doing so nothing looked to be wrong. I went ahead and got new U joints and re-balanced the driveshaft. Unfortunately the clunk is still there (2-3rd gear). Any ideas what this could be? I have the ls3 480 with a 4l70e connect and cruise kit. All other shift points are fine and no clunky noises except from 2-3. Any help would be much appreciated.

MShea

I am new to this thread but hoping someone can email me. matthew.shea21@gmail.com

new LS3 - 525 swap 70' Camaro with 4L75-E. The automotive guys that did the swap cannot figure this out and It's very disappointing to spend a sh#$ load of cash and have this horrible clunking which is much worse in D3. In D4 it only happens when shifting 2 to 3 or 3 to 2.

MShea

I'm frustrated and cannot figure out this 2/3 - 3/2 clunkI am new to this thread but hoping someone can email me directly. matthew.shea21@gmail.com

new LS376 - 525 swap 70' Camaro with 4L75-E. The automotive guys that did the swap cannot figure this out and It's very disappointing to spend a sh#$ load of cash and have this horrible clunking which is much worse in D3. In D4 it only happens when shifting 2 to 3 or 3 to 2. New driveshaft and new Yukon limited slip diff/carrier with new axels. Have replaced 4-Link lower arms and still seems like it's the rear-end loading up. If I shift manually 1-4 it's perfect or if I stay in D4 and get on the throttle it will also shift perfect. My only choice is to replace the rear-end with a new 9" currie limited slip and possibly replace the ride-tech 4-link with a newer version that does not go behind the rear seat (cutting holes for bars).

I should have kept my Turbo350 3-speed.

FranksCustomTrans

I am guessing the 4L75E uses some version of overrun mod to keep it on in all gears the plus side is greatly improves input sprag durability, The trade off 3-2 and some 2-3 clunk feel, Even without this mod GM actually did a pressure pull back in the tune at part throttle and coast down, which has probably been undone in favor of longer 3-4 clutch life.
Now assuming this is what it is , It's the nature of the beast, In really every durability / performance improvement the trade off is almost always some level of comfort or drivability loss wither it's a loppy idle from a big cam.
It always come down to which is most important, To the builder who warranty's it of course durability is going to take precedence.
Some things you can do . Lower your 3-2 coast downshift speed will make it less noticeable. or optionally check your tune see if shift time and adaptive pressure been altered.
Personally on my own car I just lowered the 3-2 mph coast and learned to live with the somewhat clunky 2-3 feel. Bear in mind on the 2-3 or 3-2 in the 60e you are not just apply or releasing a friction set but someplace in the middle while the band and 3-4 clutch or going on or off you have a neutral to some degree else you would have momentary 4th.
You would not have this with a 350 cause none of the friction applies work way you are simply adding or subtracting not both at the same moment.

MShea

I truly appreciate the help!

I'm blown away that Chevy performance parts didn't offer up this info but rather sent us a warrant new tranny. Frustrating that it doesn't do this in any other gear such as 1 to 2 / 2 to 1 or 3 to 4 / 4 to 3. Really strange and a huge disappointment for a new tranny. I guess I'll just turn up the tunes...

FranksCustomTrans

it just nature of the build.