Hope that 79 drum isnt smoked up.......he'll really feel the burn then

 

Be careful on the 3 friction overun , it's tricky to get the clearance to work , I found you literally have to cut area in fwd plate to clear that 3rd friction and thin the steels down to get it to work without applying just cause fwd is applied, Only did it a couple times, But down the road with tear downs for restores that used the overun mod , Did not see any signs of heat or excessive wear with just the 2 on refreshes . So just stay with the 2 myself.

 

maroon sent me one of his setups, the plate is stepped for it. I just wanted to do that because
-3800 Converter
-4wd
-turbocharged
hard launches.

 

hopefully it didn’t burn it up. If he did, might put a stock drum back in.

 

Like I said it can be done, Just a little tricky but if he sent you the set up , I am sure he has that all worked out.

 

Just a quick note as JUST had a customer do this , Contrary to popular thought. IT IS POSSIBLE TO PLUG IN THE TRANS PLUG REVERSED, It takes a bit more effort but can be done. With the 4L60E if you do this , You will have multiple codes but a quick tale tale is it will always be in lock and try and kill or kill the engine when placed in gear.

 

o wow, I'll have to keep this in mind......

 

finally got around to getting the trans out. Here’s the brand new yank 3800 we just put in after he decided to tow 2.5 hours one way and then back. Think it got hot? I can see stuff moving around inside it too. Lol

 

Holy cow

 

WOW and yes very hot, The small diameter converters are not up to towing. Suggest a triple disc like i have in my own car for that and a couple simple mods some will hate, Physically eliminate PWM using valve from early 4L60E VB and the sonnax spring for it with 1 check ball under it. the sonnax spring alone limits TCC pressure to about 100 psi, I found the ball increases spring tension about 20 percent so should make about 120 psi. Also while bumpy remove the check ball from input shaft. Do these or change TUNE STRATEGY PWN to 99/100 for duty cycle and seriously consider a triple disc. I have one from FTI 2800 9.5 INCH LOVE IT. Though they are pricey.
If you go triple disc no need to do the other mods except for the tuning change.
Then it will be able to tow just fine.
The issue with the small single disc is 1 not enough area and 2 the PCM cannot vary the lockup property with PWM and a high stall complicates it even more as its slips so very much on apply.

 

While on the topic of eliminating the pwm for TCC, I've read that the clutch friction materials meant for PWM some times don't like that? Is that true? And should a person use the material for non pwm?

Also with the hot converter could that be converter oil feed issue?

 

The PWM converters have no issue with on / off operation. The downside of doing so is about method. Many just block the converter regulator valve placing line pressure to the clutch . Which is probably ok with the stock tuning as the converter is only locked light throttle driving so pressure should stasy tolerable. But in cases where it been tuned to stay on at WOT OR HEAVY TOWING THROTTLES it can distort the clutch and face of the converter causing failure. Ideally elimination should be with a spring and the older or a modified newer valve and the sonnax limit spring that keep it to about 100 to 120 psi .
Now pre pwm, converters should not be used with pwm they will chatter and may fail early unless trans is modified for full on and off function.

The converter he is showing simply does not have the clutch area necessary for heavy towing and the very high stall itself causes it to slip hugely on apply.
To tow with a high stall or small diameter converter or even to lock on dyno or at WOT really needs a multidisc converter

 

yes we are going with a triple disc this time. Question. Say you built a trans for a guy 10-12 months ago. He buys a used Convertor, little 3200 Fti truck stall. But it was known as being good. The trans and everything did fine for the whole time. He has a 6.0 with a cam swapped into the truck. The guy who installed and built the engine was stalling it up and it went bam and stopped pulling. It’s the same exact converter my son had that failed when he was stalling it up (not this converter he towed with) so I’m thinking the converter failed. How much would you charge to pull the trans apart and clean it all out and put it back together in a situation like this? I want to be fair to the guy, he’s a nice respectful kid. But I don’t want to short myself either.

 

Well honestly and probably stupidly to date since i have been doing these myself outside my former employer. I have seen 3 converter failures and Have covered them all as long as only gaskets and clean up involved. But if i were going to charge. I would want at least 500 for tear down , clean up , reassembly plus materials. And most would say IMO that was too cheap. Considering that the time involved in clean up after a major converter failure can be as much as a full rebuild.
Last one I did had a whole day in as stuff was in everything every place as the little screen in pump had ruptured and let stuff into everything.

 

The total usable travel of the sonnax servo is 0.215 this why I say it's imperative the band clearance be as close as possible without dragging the drum. And bear in mind that will open up a little after a few applies.

 

4L60E and the 3-4 clutch.
I see many with 3-4 clutch failures in pretty short order after a rebuild. The talk of the best frictions they put in and how many. The Clearances ETC.
But here is reality. The 3-4 circuit in the 4l60e has many possible leak points/ Drum to shaft- stator tube- stator tube to pump half- bore plugs- check ball release valves in case and drum - band pin to case when in both 3rd and 4th gear (In third this happens via the 3rd accum oil in servo bore to vented 4th circuit at band pin and in 4th via the servo feed oil leaking to case. It is a substantial leak in most cases I have found. )
If you want the 3-4 set to live regardless of friction type or number all of these must be checked and addressed as needed. In my builds I just address them all as if they are leaking. With the exception of the DRUM to shaft I address that only if its leaking after being checkl cold and hot as IMO removing the shaft from the drum needlessly actually increases the possibility of a leak down the line.
Also do not assume aftermarket of reman drums are not leaking. To the best of my knowledge only the Sonnax smart drum uses a NEW GM drum.
But in the 3-4 circuit unless you check and or address these.
DRUM TO SHAFT-STATOR TUBE-STATOR TUBE TO PUMP-RELEASE CHECKVALVE BALL AND SEAT-BORE PLUGS- BAND PIN TO CASE. Leaks you have not fixed the trans and no matter what frictions, steels. number. type, clearance you use it will fail unless these are addressed.
Also failed to mention if you replace- swap- mixup pump halves BOTH must be machined else you will have a leak here also. Every pump I have placed on lathe is warped without exception. As long as they are matched and aligned back with each other as the sides from turning them do warp together you are likely ok . But I have noted You must turn or replace both halves with Newly machined halves if either is swapped or replaces from its original partner.
Another bad leak area is the boost valve bore this can cause lower cruise line in particular and burn the 3-4 clutch and band at light to part throttle just driving.
If you cant or dont do all of the following you are NOT fixing the trans and can expect failure, It is not the trans fault. It is failure to address these things.
I would trust the cheapest paper frictions made with the hydraulics mentioned addressed every time to the best frictions made and these not dealt with.

 

Just a note, I just had a guy contact me, He had a slipping 4th gear, He was running the sonnax servo. The unit had been in service over a year about 10k miles (not my build) I had him remove the servo disassemble and inspect The outer small servo had shrunk and was leaking badly. I ask him if he was using a heat shield he said no. I sent him a servo ring kit to replace it (he could not find any in stock anyplace) He replaced and all is good though I suspect band probably toasted a little. I would say the heat from the catalytic converter caused the seal to shrink and get hard. GM did put those thee for a reason,

 

Just installed one of the "gently oversized" AFL valves. certainly fits tighter with just a little rub. While I did not do a vac test I did do and before and after leak down test with a super thin sewing machine oil I have , The result was the stock valve drained out in about 10 minutes. The GOS valve channel was still full 2 hours later . both with VB at about 70f temperature wise. Didn't have time to set up a vac test or see how it does at varying temperatures. But with my simple test seems good. May use more as a lot less hassle than boring and all for the sonnax oversized valve and being a 1 man show anything that can save time and do the trick is always welcome.

Another note with my oringed band pins, I am doing my first refresh on one with this mod now, Did preliminary air test though 4th feed hole in case no notable air leaks. Inspected the green orings no notable wear or damage green coating still there. Slight flattening of the outside of ring expected. 30k miles. reason for refresh just because . found no notable wear or damage in unit. Customer says they beat on it hard with 700 Awhp 4x4 6000lb truck used for performance and towing camper trailer. Fluid a little dark but then they are towing with a 3200 stall triple disc .

Ever so slight burnish on overrun frictions I assume due to in and out of OD constantly while towing cycling them on a off but so slight could without question be reused if i did that stuff.

Also have added a 3rd oring to band pin as noted 3rd accum oil leaking past servo though pin bore and out small hole in case, addition of this ring stopped this leak.

Just a few notes to those interested .

 

Although I dont do a fraction of units most of you guys do, everyone that I have done got an oversized AFL valve from Central Valve Bodies.

 

Well I was impressed it fit just ever so slightly tighter but still moved well and seems to seal well, Since it has such a high spring force I do no see any issues should work well, But will see.
I did while i had it out add an oring to the end cap towards EPC also.