My 1998 Z28 with 344,000 miles on it has an oil leak and the trans must come out. I have an A4 with removable bell housing 97-02 that I am going to have rebuilt by a GM tech in his spare time. I am in need of a regular HD stockish torque converter to put in. I have a stall now and am tired of it. This is my DD part time along side my Corvette. I do not track the car so I am wanting an inexpensive torque converter and my local guy Revmax no longer will sell me a stocker so I need something else, what I'm not sure because my funds are limited for this build.

I'm pretty sure I'm going to use this kit, Trutech Street Performer rebuild kit Alto Red Eagle & Raybestos GPZ 97-03 4L60E. I see people write about things like Corvette servos and 5 Gear Planetary systems. Should I really get a Corvette servo, they are fairly cheap? What all is involved in replacing my 4 Gear Planet with a 5 Gear? Remember cost is an issue. I'm really looking for an open discussion on these things because although I've been repairing cars since 1969 my A/T knowledge is my weakest point. Any Help would be appreciated.

 

A high quality built to your specs stock stall converter can be had from a sponsor for about $500. Mine is from Circle D and I'm quite happy with how it drives. I wanted a stock stall for my DD to go with my freshly rebuilt trans. A generic stock converter can be had for around $200 and as long as you get one of the more reputable manufacturer, I hear they're fine for DD's. You'd have to ask other members for what brands are the good generics.

 

I'd get the corvette servo, you're certain your car doesn't already have one? They're stock on a lot of cars.

If it's just a DD I wouldn't think the planetary gear upgrade would be worth it unless you suspect there's an issue with the 4 gear already present.

 

To start with, I am a newbie auto trans guy as well. The info I've been finding about pinions... do not replace OEM 4 pinions with aftermarket 5 pinion planets. supposedly they are weaker. OEM 5 pinion planets are around $250! I am sticking with my original 4 pinion planets in my rebuild. I would add the corvette servo.

 

So yea looking at 5 gear pinions I would only go with GM, having said that there are front and rear pinions?, do I need to replace these both as a set and are there any other parts that are needed when you replace this/these?

 

Yes, only get OEM 5 pinion planetaries IF you decide to do that upgrade.

To OP, given your budget and that this is a DD, unless you suspect something is wrong with the stock one I'd consider leaving it in. That's a lot of money that could be spent elsewhere. They show their value in high HP track cars.

 

I'm looking at a couple of no name converters on ebay, don't want to spend a bunch of money for a stocker but also do not want to buy junk. What about this Corvette servo I'm hearing about?

 

corvette servo is like $10
Get a Dacco converter. Not sure I see the point of five pinion planetaries behind a budget converter. Or even a stock converter.
People run original 4 pinion behind faster cars and trucks.

 

Any Transmission supply warehouse should be able to get all the parts you need for far cheaper than even ebay.

corvette servo is $8.62 from my supplier
Stock Stall Torque converter is usualy 130 ish with 50 dollar core.

DO NOT replace 4 pinions with 5 pinions. I've never ever (even in 1000 hp 4000 lb cars) seen a 4 pinion blow up. Ever. I've seen them get ruined from lack of lube...but a 5 pinion will suffer the same fate. The 5 pinion is actually different in construction than the 4 pinions and really no stronger.

A super simple "mod" list for a daily driver, should be less than 75 bucks:
-$9Corvette servo (if you don't already have one but I bet you do)
-$13 Boost valve-Sonnax .490 or transgo .500 both fine. Transgo usually cheaper
-$23Wide carbon NOT KEVLAR 2-4 band.
-$20Sonnax o-ring end plugs. Vacuum testing valve bodies shows this to be a SUPER common issue across almost all valve bodies. Ensuring you fix this circuit leak is a big benefit in making the trans last and it's something I check (and usually have to replace) on every build.

I personally use NEW ELECTRONICS. Some guys dont...your budget will determine it for you. This is something that I do on every single build. It's about 120 bucks, but you get shift solenoids, 3-2 solenoid, TCC solenoid, pressure switch, and EPC. It's always worth the money to me to avoid problems before they arise. A solenoid can OHM test 100% fine. You can even hear it "Click" when energized, and it can still have an internal plug from clutch material or just be worn out and not sealing off fluid pressure correctly.

Also, just use standard tan clutches throughout the entire trans except the 3/4's. There's no benefit in this trans to use red alto or blue/green GPZ clutches. Myself and most builders have best success with Borg Warner High Energy clutches (I use 6 clutches with .006-.008 ish clearance per fiber on a daily driver build) for the 3/4.

Other than that, just a standard rebuild with new seals/gaskets and proper attention to detail should be a very durable daily driver trans. You can drill separator plate for free and get better shift feel and holding capacity. Plenty of threads on here to help with hole sizes.

 

 

Be sure not to mix the Sonnax capsule metering valve with a TransGo shift kit. You could get a 2-3 flare shift. I personally would not use it at all.

 

After a lot of research on a budget converter I'm installing the i6 Trailblazer stall. Dacco part number B85VJCX. Autozone is the cheapest place I've found it for $169 plus core. From everything I've found it will flash from 21-2800 rpm depending on power and one guys flashed to 3400. The 3400 was behind a Maggie supercharged 5.3 in a truck and lived 4 years and 134,000 miles. Not much info to be found here on them but truck and gto forums have plenty of reading.

 

bbond105, how exactly is the servo release check valve supposed to work?

Sonnax says this

"Inadequate metering of 2nd gear band servo release oil causes 3-4 clutch failure. The 3-4 clutch and 2nd gear band are not properly synchronized. Sonnax servo release check valve kit 77701-076 is a unique solution that combines an orifice with a ball check valve to resolve these problems.

Improved design meters servo release oil, reducing 3-4 clutch failure
Provides sufficient exhaust so that 3-2 downshifts are smooth
Calibrates 3-4 clutch feed orifice without creating shift concerns"

But unless you're an expert, it's not really clear what it's alleging to do. Full disclosure, I have it in my build (with Sonnax shift kit). In hindsight, I wouldn't install it because I don't think I've come across a single instance on these forums where someone said "this fixed or improved my vehicle".

 

Alot of this is not really needed for the daily driver build outlined in this post

 

It is an orificed plug that changes the band release time by restricting oil flow. It slows it down to accomodate the often slow engagement of the 3/4's. Timing the release closer to the apply to avoid a flare.

The servo and 3/4 clutch relationship is an interesting one for those that don't understand. The 2nd servo applys the 2-4 band for 2nd gear. That's plenty obvious. When 3rd gear oil comes on, it is direced to the backside of the 2nd gear servo at the same time it's directed to the 3-4 clutches. The oil headed to the back side of the servo builds pressure and overcomes the 2nd gear apply oil on the other side. This releases the band. The fluid volume and time it takes to fill that volume acts as an accumulator. The same way the piston and volume of the cylinder for the 1-2 accumulator and 3-4 accumulator work.

So, when selecting spring pressures, orifice sizes in the separator plate, etc it all needs to work together. it needs to time the band release with the 3-4 clutch apply using the same feed oil. In a stock application the sonnax plug is *ok* at best in my opinion.

When making changes to the separator plate drill sizes, this sonnax plug is no longer sized to match and becomes more of a hinderance than a help.

I Just reseat the stock check ball capsule and never use the sonnax piece here. If i get a unit for a rebuild that has one, I remove it, also remove the stock capsule, and replace with a new GM capsule.

 

Thank you for the explanation, MaroonMonsterLS1!

 

Great info thanx guys. I was actually looking at an ACC Night Stalker torque converter but I see some bad reviews but I guess everything get bad reviews if you look for them.

 

MaroonMonsterLS1 is giving excellent and perfect advice. His post #9 is spot on for a basic rebuild. For a tiny improvement, I would go with 7 frictions for the 3/4 clutch, either Borg Warner High Energy or Raybestos GPZ. And notice how he correctly lists the clearance PER FRICTION instead of just for the entire clutch.

And forget about the 5-pinion planets as they are rarely worth the price; also to use the new GM 5-pinion, you have to upgrade to the new reaction shaft and bearing or you will have instant bearing failure.

As he suggests, spend the $120 for a set of solenoids and internal harness; your are 20 years old and almost guaranteed to fail soon and/or already be flaky.

TruTech is an excellent source for part kits and owner Jeff will give you over-the-phone help. However, any trans shop can buy the parts cheaper through their distributor(s).

 

Bit surprised you want a new reaction shaft; I think (but not absolutely sure) that the new reaction shaft works with the old planets. The opposite is not true - the new GM planets, especially the 5-pinion planet, absolutely needs the new reaction shaft and new bearing.

The Sonnax 4th servo looks cool, but is really only needed if you will have high loads in 4th gear - e.g. towing a trailor and racing at 120+ mph.

And as mentioned, skip the Sonnax Servo Release Check Valve (capsule metering valve).

 

yes, I'm purchasing this kit......

https://www.ebay.com/itm/Trutech-Str...53.m1438.l2649