gmachala404

I just got my 71 Chevelle LS3/4L65E combo running. Just noticed an odd sound
that seems to be coming from inside the transmission. Made this noise right out of
the box when I first cranked it. When I start the car cold
(70 degrees) it is quiet. If I let it idle for about 5 minutes the noise starts up.
I can actually feel it in the body of the car like a high frequency buzz
or vibration I call it a whirring sound. It occurs in all gears and while driving.
It does stop occasionally and then restart again. It kind of ruins my cool muted
exhaust note. It wouldn't be so noticeable if I had louder mufflers. I have been
reading posts and it seems it may be the pressure regulator making this noise.
I just spent a ton of money on this built transmission and its hella difficult to get
it into and out of this car (very tight fit). Any suggestions on what it is and what
can be done to eliminate this irritating noise?

mrvedit

I'm no trans expert, but here is what I would do:
1. Pull the electrical connector and try it again. The trans will go into limp mode, but the pressure regulator (often called force motor) won't be getting any signals from the PCM/TCM. If this turns off the noise, I would first connect a ground strap to the trans.
2. You only have to drop the trans pan to replace the force motor; with the pan off it is literally a 2-minute job and might cost you $35.

Perhaps someone with more experience knows exactly what this is.
BTW - My first car as a teenager was a 3-year old 1970 SS 454; I always like the '71 sheet metal better. Sound like it will be a FUN car!

Brian68

Putting the trans into limp mode by dropping the power to the force motor (pressure control solenoid) will cause a full line pressure command, which is possibly the problem anyway. First things first. Are those PITA little plastic shields on either side of the front trans rubbing on the flexplate? What it sounds more like is a cracked filter allowing air into the pump and causing cavitation. You did fill the trans correctly right? Not trying to be a smart *** but the 4L's are really touchy about fluid level, especially the deep pans.

gmachala404

Unsure about fluid level as dipstick is aftermarket. But is between lines hot level in park. Really upset right now cause trans was 3k and is a pain to get out. Ill pull the pan nd check filter. I can feel the whining vibration in shifter. Itcomes and goes.

gmachala404

My HP tuners scanner says 120psi line pressure on tcc

gmachala404

It's a deep pan

gmachala404

The trans is at 5° downward angle too. It has a small but broad depression /dent in pan from shipping too.

mrvedit

Very sorry for this stupid question - but are you checking fluid level with the engine running?
Do you remember how much fluid you put in?
I recall putting 10 quarts in mine; trans takes twice as much as an engine.
Again, sorry if this is all obvious to you.

gmachala404

Yeah I put about 1 quart in converter then 11 quarts in after that. I
couldn't check the level right away after I fired the crate engine cause
it wouldn't idle. After a bit of tuning I was able to idle it and check
fluid. It was overfilled so I drained a bit out and went to break in
the rings. I noticed the whiny sound the first time I cranked it up.
Thought it was something simple so ignored it at first. I checked
fluid and it was right but since I have a 5 degree slant to my trans
I decided I would try to drain some out anyway that maybe it was
foaming up and cavitating. But that did no good. I tried draining
a pint out at a time and it didn't help. I pulled the pan off tonight
and nothing jumps out at all. No residue in the pan. The noise reminds
me of a power steering pump whine of the old 70's Fords. It is
super irritating and seems worse in the car. When it stops its like a
thank you Jesus moment.

gmachala404

I pulled the filter off it looks good. However, under the filter I found a
connector that wasn't plugged in to anything. It is a blue connector on
the front of the transmissions valve body.

Vince B

iTrader: (1)

That plug is just an extra one because of the aftermarket internal wiring harness that was used. I would contact your builder to see what they want to do here. Sounds like a pump issue IMO.

gmachala404

I contacted the shop I got the transmission from And it turns out another shop built it for them. So I am trying to contact them. Meanwhile I checked the ID numbers on the transmission and determined its case at least is from a 2002 4.3L truck application. That doesn't sound good at all.
I found the builder's website and it just looks like a stock transmission rebuilder.

gmachala404

Can anyone confirm if the filter in the pictures is for a shallow deep pan?

mrvedit

A trans expert should confirm this, but from everything I have read in the ATSG guides and elsewhere, all the 4L60E built at one time have the same internals and main case, regardless of what vehicle they go into. According to the ATSG Update manual, a lot of internal parts were strengthened in 2002, including a heat treated sunshell. So, I wouldn't worry about the ID #; it all comes down to the quality of the rebuild. All just my opinion.

gmachala404

Thanks for the info guys. I put the filter back on and noticed it went on much farther than it was on there and is firmly in place and not floppy. I put the pan back on and filled it up and cranked it. The sound started again after about 30 seconds of run time. So that wasn't it. So, I followed Gilberts's advice from ACE Racing Transmissions (forum sponsor) and unbolted the converter from the flywheel and pushed it back and spun it and it spins easily. Then I cranked it without the converter attached and no noise at all. Sounds a whole lot more like an engine so it must be making quite a bit of noise all the time and the whine that comes and goes adds to it quite a bit. So, its definitely transmission. I am pulling it and taking it to Gilbert on the 18th. It will be a pain pain pain getting it out cause its in there like a turtle in a shell :-( While its out I think I will just break down and cut the floor pan and give the trans more room. Hate to do it but it is so tight.

Gilbert@Ace Racing

It was nice talking to you earlier today. Always good to meet fellow gear heads!

Like I said earlier, stay in touch here and there and once you get it here we'll crack it open and see what it's biggest problem is and go from there. No doubt I'll solve your problem and make recommendations for changes or upgrades if I think they are warranted.

Looking forward to meeting you in person!

g

Brian68

That would **** me off. If I wanted them to build it, I would have taken it there.

Vince B

iTrader: (1)

Yes that is the correct filter for the pan being used. I have a lot of faith in Gil and I know you will be in good hands. Please update the thread when we find out what was wrong here!