with the help of Vince and many on here, I completed my build in January. I converted to a 4l65e with a billet output shaft and upgraded internals throughout. I have 10,000 solid miles but now I have two distinct problems that I'm pretty sure are related.

First, the tranny:

Re-man core, built at home. BW clutches and steels, Sonnax servos, Sonnax pinless accumulators, HD-2 shift kit, Billet output shaft, BW sprag, stock but rebuilt pump, Beast sun shell, OEM Delco 5 pinion planets, etc.

I built the tranny within specs using the ATSG manuals, following manufacturer's specs for the other stuff, etc. I took my time and did it right.

The only thing that I re-used is the harness/solenoids

The converter is a Yank TT3000. It had 40k on it and I sent it back to Yank for a cut and clean. The clutch was replaced as well. Nobody else has ever touched it



Anyway, It has been flawless until a week or two ago.

Problem 1: It has a shimmy or a shudder after it goes into 4th during lockup. Either at light throttle/cruising, or during acceleration before it comes out of lockup. It shakes a bit, I thought it was a misfire at first. It happens more under a load, like going up an incline, but will also happen on flat ground. It is intermittent and does not happen every time. I have been able to get it to happen during cruise control also. Only in lockup. moderate driving, it acts just fine.

Problem 2: During full throttle shifts, either manually shifting or when in drive, it over revs going from 2-3 and 3-4. It seems like a slip, but it's not (or maybe it is?), if that makes sense. At least is not the clutches slipping. Maybe it's the converter? I don't really know for sure what a converter slip feels like. when it shifts, it revs up like a bad shift on a manual tranny. It revs way up and hangs there a second before in finally grabs the next gear.

Problem 1 made me think it was electronic, but problem 2 (which has gotten progressively worse) makes me think it is mechanical.


I'm not looking for a shotgun diagnoses, I just need some help starting in the right area. I would like to drop the pan to check the fluid anyway, change the filter etc.

On the dipstick, the fluid is brown-ish and doesn't smell quite right.


I have limited experience with converters, but this is where I am leaning.

thoughts?

 

Brownish fluid means you have all your clutch material in liquid form. I'd bet your 3rd and 4th clutches are toast, they're the weak spot in 4L60E transmissions. Your over-rev on the shifting is going to be slipping clutches, I'm not sure why you think otherwise regardless of how long ago it was built? Your setup isn't really putting down enough power to blow through a torque converter.

Start with replacing the filter for sure, if you've got a lot of clutch material in it you may be running out of line pressure to hold the clutch packs.

 

It only revs up like that at 100% throttle at the end of the gear. Otherwise there is no problem, other than the intermittent stutter in lockup. 80% of the time it drives fine. The last tranny I had, had the clutches slip and eventually burn up, and this feels totally different.

 

WOT slip is clutch slip. You're running out of holding power on the packs. OR there is an internal malfunction (line pressure) preventing the transmission from shifting when commanded.

 

Do have a way to log it???

Was the transmission tables tuned after you built it???

Brownish fluid is a bad sign. It's usually an indication of slippage and heat.

 

Sounds like your lockup clutch is toast. It's probably sending lock up clutch material through the trans. For problem 2, when the trans shifts from 2-3 the band has to disengage while the 3-4 clutch pack engages simotaniously. If this is not timed perfectly you will get that slip feeling when it's not actually slipping but it's engaging 1st gear for a split second. In time this will burn up the 3-4 clutch pack.

 

Or... 3-4 clutches are already screwed and you're really feeling it when the converter goes into lockup.

 

****

I don't have a way to log it.

The PCM was already tuned from Nelson for the previous tranny, which was the same, minus some internal hard parts.

Also, I have 80% torque management removed, which I realize is kind of dumb. I might as well have it all removed.


Since I don't have a way to check the lockup clutch, it looks like I'll be pulling the tranny to check the clutches, which would be faster than waiting for the converter to come back.

This sucks

Edit: I really feel like the problem lies in the converter. I don't have enough experience to back this up, but both problems started at the same time, and this slip feels way different than the slip from when the clutches went out.

I'll call Yank this week and see what they think as well.

My biggest problem is time. I don't have any. I'll have to get this diagnosed as close as possible and hopefully have it pinpointed so I can get it banged out in a weekend.


Thanks for all your input thus far. This place has been a tremendous help.

 

I hope you can get it figured out. This stuff can really suck sometimes.

 

So I noticed a new noise this morning. It may not be new but I usually have the radio on. It has that sound like when a bearing goes bad. Like whirring sound. In every gear. The more I accelerate the more I hear it. I pulled into a parking lot and out it in park and revved it up a little. I can still hear it. Everything at this point points to the converter. If you have any ideas that point to the clutch packs please let me know. The biggest frustration is I can't check the converter myself

I have a stock converter i can swap in temporarily. Will this be okay with the tune?