SLOW GTO

iTrader: (7)

I installed my built trans last week. I have all gears 1-4 and reverse and converter locks up in 4th like normal, the problem I’m having is if I want to down shift into 1st 2nd or 3rd I don’t get any engine braking, the car just goes to like a neutral state and will start to rev and once I hit the rpm that would equal the gear I’m into it will engage and start to work. For example going 60mph in 4th gear I drop the car into 2nd gear car's rpms sit at 1800 to 2000rpms I have to give the car gas once it hits the 5000rpm the car will start to accelerate. I contacted the trans builder and he's clueless? Anyone out there have similar problem and or solution? Any input would be greatly appreciated.


Thank You.
Ernie.
__________________



Here is a video.

http://youtu.be/GSTj1Xgtj9A

Gilbert@Ace Racing

About the only way you will not have engine braking is if the over run clutches are not being applied locking the input sprag hub. Of everything else works fine, then there is an issue in the input drum in my opinion.

g

SLOW GTO

iTrader: (7)

Gilbert thank you for the reply. Will pass this info onto my trans builder.

SLOW GTO

iTrader: (7)

Heres the problem as to why my trans does not give any engine braking.

Just got this picture from the trans builder.

Gilbert@Ace Racing

The lip seal has rolled because the overrunning clutch hyper extended itself when it applied. Basically it came too far out of the forward piston.

You're builder is using a stamped steel forward piston with the bonded seals which is a good idea, but not in conjunction with an early type cast aluminum overrunning clutch piston which has been cut for a sleeved drum. That is a no no my friend, this will happen time and time again. I see it all the time.

g

SLOW GTO

iTrader: (7)

Gilbert, thank you again for the reply. So what would be the fix for this problem? Replace overrunning clutch piston with steel type? Your input is greatly appreciated.

Ernie.

Gilbert@Ace Racing

Well there are several different combinations of those pistons that have been used to a certain degree of success over the years. Some work at one level, others work at another. The trick is understanding which combination should be used and when.

And then of course there are some outfits that are using proprietary components as well.

g

SLOW GTO

iTrader: (7)

Had to pull my trans back out, to get the overrun piston problem solved. I put trans back in and noticed right away when going into reverse car felt like it was against a wall and did not want to really move without giving the car a good amount of gas, almost felt like trans was stuck in two gears at once in reverse. 2nd problem I noticed when putting the car into neutral car would move forward at idle and if I rev the car up to 3,000 rpms car would start to drive forward and can get up to 30+ mph in neutral. Drove the car for a good 60miles went to the dyno and after that car lost reverse!. So pulled trans back out, got it back to trans builder he said it had split a seal on the shaft and that’s why reverse felt like that and then burned up and out!. I just got the trans back Friday and back in the car, and now my new problem is everything is working (so far gears 1-4 good, reverse good) except again when putting car into neutral car does not move forward like it did before, but still if I stab the gas pedal car will still move forward in neutral. What would cause this? Already talked to trans builder and thinks it’s my line pressure? Anyone ever hear of this? Is it safe to be driving on this trans?

Cam72aro

iTrader: (28)

I would find a different trans builder. It appears that he doesn't know what he is doing.

SLOW GTO

iTrader: (7)

I know it appears that away, just having some bad luck he said with mine, he said to me he has built a ton of 4L60's and never no issues. He has been building race transmissions for the last 20+ years and has a few 7 second cars with his built transmissions in them. There is no way i can go to a different trans builder now, I’m already out $2,500+ and no one is going to warranty his work. I’m just trying to get my trans done right; any help would be greatly appreciated. Trust me I’m not having any fun pulling my trans every time, i have had it!

chrs1313

iTrader: (24)

Talk to the guys at FLT I am sure they can work something out for you...they are vary fair and honest and built stuff the right way...

tell them I sent ya over...

Also we still need to hook up and get a ram air on that car

Cam72aro

iTrader: (28)

$2500 and you have a 4l65e? You could be into an 80 for less that. Is he charging you every time he works on it? If he is, then shame on him, its his f up.

NVR_SPDS

iTrader: (39)

Not knocking your builder at all, and I dont doubt he has built some solid transmissions, but there is a reason builders specialize in specific units.

Companies such as RPM Transmissions(Best company IMHO), FLT, Ace and others specialize in certain units because there are tricks to building every unit for applications such as ours. Im no expert, but I know the 4L60e can be a finicky bastard. Take what Gilbert said for example, you just showed him a pic of what was wrong, and he told you the issue straight away. It takes experience with certain units/apps to build quality parts, and thats the reason I ended up going with FLT over a local builder.

Ive recently had a built trans fail, so I know how you feel.

PBA

When using the steel forward molded rubber piston along with the aluminum overrun piston, you must machine down the legs of the forward piston to get the overrun clutch clearance down to .015" - .025". This will stop the overrun piston from coming up to high and letting the outer seal come out of its groove. The setup as you have it now, will let the overun piston travel apx. .040" - .050", which is way to much when using the steel forward piston along with the aluminum overrun piston. The steel forward piston has a tapered wall where the outer seal of the overrun piston applies, the aluminum forward piston does not have this, therefore the outer seal does not come out of its groove. The other fix is to use the forged forward aluminum piston from Sonnax. Expensive, but will solve your problem. I have many customers using these modified steel forward piston along with the aluminum overrun piston setup without any problems. Have your builder call me and I will help him out here on this. Dana

Gilbert@Ace Racing

Thanks for the respect guys, I do appreciate the kind words.

We solved the mismatched parts issue with his forward / overrunning pistons Dana. That's a non issue at this point... assuming the new stuff was installed properly. Stranger things have happened though!

As far as the builder on this unit. He's a good guy. I've talked to the OP and a builder I know and trust in that immediate area who has respect for him. Everybody has a bad day, and every builder gets snake bit on a particular unit from time to time.

I don't see the current symptom being an issue. I need to give it some thought. In Park, Reverse and manual Low the Low/Reverse clutch pack is applied. And no elements are applied in Neutral. I would suspect a crossleak in the valve body creating a situation where the low/reverse circuit is being fed pressure when it's in Neutral and you increase the line pressure by raising rpm's.

What's interesting is my 2000 Z28 DD with 190k miles will rock forward when I start it and tickle the throttle in park. It is a bone stock, I mean still has every part GM put on it bone stock car and the transmission is doing fine. But, keep in mind it has a bone stock tight *** torque converter too. A loose converter would not allow the car to rock forward a bit. What I feel in mine is the pump making good pressure right at start up and the low/reverse piston stroking when it gets fed that pressure and of course the clutches grabbing which makes the car want to move forward slightly. I know my "symptom" is not detrimental to the tranny, in fact it's perfectly normal. And of course I happen to know a good tranny builder who can handle it when it goes legs up!

I say run the **** out of it and it oughta be fine.

g

Andy @ FLT

Thanks Chris,
to the op if you need help just give us a call.
Andy