moli6den

I'm rebuilding 700R4 from my 90 Camaro. Trans went out because of tear in the separator plate beetwen 1-2 and 3-4 accumulator. It's not my first rebuild of automatic transmission so I decided to do some upgrades (Transgo 700 2-3, Corvette servo, new input drum with superior rapid relief valve etc.) and also I replaced 3rd accumulator checkball. After replacement I installed 2-4 servo and performed "leak checking procedure" from ATSG manual (THM 700-R4 [4L60] 1987-1993) page 51. I poured some nitro thinner in 3rd accumulator passage and unfortunatley I saw leaking checkball inside the case. I was suprised becasue I have done this test on used capsules few times earlier and always there was no leaking inside the case (except orificed cup plug of course). After failed test from ATSG I decided to perform test with ATF under pressure. I sealed my airgun to the case with some piece of rubber. With pressure above 100psi there was no leak from capsule; oil from orificed cup plug almost hit opposite wall inside the case. With lower pressure and with no pressure there was also no leak.

Here comes my question: Is ATSG test trustworthy? Can I sleep peacefully with my fresh installed capsule or shoud I try another one?

mrvedit

Well, I'm certainly no rebuild expert, but if it seals with ATF, I think you are good to go.

I am very curious how you tested this with ATF under pressure. Do you have a picture?

coryforsenate

iTrader: (1)

I've seen the test done with a 50/50 mix of ATF and mineral spirits. I imagine the spirits are there to thin out the ATF and let leaks show without the need for applying pressure.

moli6den

This photo is not from my trans.



I use piece of rubber to seal area marked with red circle. I make a small hole in the rubber to install my airgun. Servo 2-4 was installed to close servo bore. First I put some ATF in the circled area. After that I was blowing air in the 3rd acc checkball passage and watching leaks inside the case. Repeated that operations a couple of times. There was no leaks at all. Only orificed cup plug was exhausting fluid.

PBA

A little leakage is normal. Just use high pressure air to blow out any residue from both sides of the capsule and take a long drift a tap on the checkball a few tomes lightly to make sure that you have a "good seat" for the checkball. I have never seen a bad checkball capsule when it is cleaned out with solvent or mineral spirits and blown dry with high pressure air. What orifice cup plug are you talking about here?

moli6den

I menat that orificed cup plug in red circle. Fluid was bleeding on the other side - inside the case.

PBA

That is a lube hole to spray oil on the 2-4 band. Make sure it is open.

moli6den

Yes it is squirting oil all the time when pressure is applied. But here comes my next question. In 4th accumulator bore the same orificed cup plug is located. Transgo 2-3 kit says that I have to block 4th accumulator with plug so there would be no oil squirting inside the case from the accumulator. I thought that oil is important to lube rear planets in 4th gear. Am I right? Should I figure different way to block 4th accumulator?

mrvedit

I've only seen the directions for the Trango HD2 kit, but it certainly does not have you block any accumulators or their bleed holes.
IMHO some of the Transgo 4L60E kit directions seem to be carry-overs from the 700R4 and don't take the 4L60E differences/factory-upgrades into account. Probably why most performance builders say "modified Transgo shiftkit" because they know not to implement all of it.

As an example, Chuck from FLT recently told me not to use the Transgo orifice in place of the check ball capsule in the input drum. Transgo claims it is for high RPM operation, but Chuck said he uses the stock setup in 9 second cars running 8000 RPM.

Perhaps Dana (PBA) can augment or correct my comments.

PBA

Even when you block the 4th accumulator hole, there is still some 3rd accumulator oil so there will always be oil spraying on the rear bearing. I only recommend using the orifice when you get near 7,000 rpm, and this is to cover myself if the 3-4 piston did not come on due the checkball capsule not letting the checkball seat. If you are using large apply feed holes (.120" & larger), then this should never be a problem. But when you use the TransGo (very conservative) apply feed hole sizes, then you probably could run into a checkball seating problem. In my builds I block off the checkball capsule and add a .035" hole at the bottom of the drum on the outside edge just under the piston outer seal if it is going over 7,000 rpm. I did the same for the TH350 & TH400 when going to hi-rpm. Never had a problem in the last 35 years. Never use the restrictors that come in all the TransGo Shift kits for the reverse/input piston. Doing this will cause centrifuge problems if the motor goes over 5,500 rpm. If you have already installed them in the reverse/input piston, then drill "one" of the restrictors out to .065" - .070", to prevent the centrifuge problem already mentioned. I have several 700R4/4L60E's going over 8,000 rpm, and none of these have a clutch apply problem on the 2-3 shift. The original carry-overs (700R4 to 4L60E) worked fine in the 1993 - 1995 units, but when the 1996 transmission came out, some of the carry-overs did not work all the time as in earlier models. This is one of the reasons for TransGo to go conservative on just about everything. To use the earlier hole sizes in the separator plate other modifications needed to be implemented. This should help out some.

moli6den

Thanks for comprehensive answer!

I'm not going to rev more than 5500rpm but installed TransGo 7-CS and Superior rapid relief valve (K070) just in case. I'm going to use 3rd apply hole 0.157 just like TransGo 700 2-3 manual says.

I really want to have nice and clean 2-3 shift in that transmission. So I wonder if I use all TransGo hole sizes (3rd-0.157, 2nd-0.86-0.93, 3-2-0.110, 3rd exhaust-0.157) with 0.500 boost valve, 3-4 about .040 clearance and band clearance about .085 there would be no overlap or flare shift? I thought that Sonnax Servo Release Check Valve Kit (77701-076) would be magic wand to 2-3 shift but I found info that is only a restrictor to 3rd accumulator oil to slow servo band relase and it's more trouble than it's worth.

PBA

When using the 700R4 TransGo Shift kit or Performance Shift, DO NOT use the 77701-076 setup. TransGo has the holes in the separator plate sized and or blocked to what they want to address any 2-3 shift problems. TransGo will tell you not add the Sonnax 77701-076 setup here with their Shift kits, as it will create problems instead of solving them. Sonnax has there way of addressing the problem, and TransGo another. I prefer TransGo's way of addressing them.

With a 10" or smaller diameter torque converter,
2nd = .093" - .099".
3rd = .157" - .187".
Band Release .110" - .116".
4th = .157" - .203".
3-2 = .157" - .187". If you drive conservative, go with the smaller hole size, aggressive, larger hole sizes.

With stock diameter torque converter,
2nd = .076" - .086".
3rd = .110" - .135".
Band Release .110" - .116".
4th = .125" - .157".
3-2 = .125" - .157". If you drive conservative, go with the smaller hole size, aggressive, larger hole sizes.
These hole sizes (2nd, 3rd, & Band Release) are when using the Corvette servo.

moli6den

Unfortunately I have to stay with stock stall speed converter (1600rpm) for now.

Do you know how to check output shaft endplay properly? I bought Sonnax 77406-10 but in the instructions they didn't mention how to do that and what amount of play output shaft should have. Does output shaft endplay affect front unit endplay?

I'm wondering what is the best way to adjust the servo band. Do you use TransGo methods (big shims between 4th piston and cover OR small shims inside 2nd piston behind steel cover and snap ring discarded) or maybe just weld servo pin to lengthen it?

PBA

Output shaft does not effect the input shaft endplay. It is not critical. If you want to keep the 1-2 part throttle shifts smooth and still have firm WOT shifts, (this is the best way for longevity) follow the TransGo Junior instructions. I combine the 700-2-3 & the TransGo Junior to get the best of both worlds. In the valve body use the Black 2nd accumulator spring with "A" or "B" accumulator and use the Red spring in the line bias valve setup. Always install the Red spring and "one" aluminum shim when setting up the Throttle Valve assembly. Make sure that the spacer that goes inside the Red TV Spring is flat as they are bent slightly from TransGo. If you combine both kits, install two of the spacers inside the Red Spring. Again this works best for very responsive pressure rise (line rise). I use the big shim to adjust the band clearance. You want minimum band clearance. Make sure that the big gold shim is flat, I have found them bent on many occasions and have to flatten them back out to use them. Sonnax has a longer apply pin with seals and I have them if you need one. With the stock diameter torque converter use the above hole sizes in the separator plate for the best results.

moli6den

I have only TransGo 700-2&3 kit which has white and brown spring for accumulator valve and no spring for 1-2 accumulator piston. Can I use stock yellow spring for 1-2 acc piston from used transmission? I'm asking because my stock yellow spring had broken and destroyed separator plate and 1-2 acc cover.

If I want to go with full manual option I have to use spring to block weights in the governor. Do I have to disassemble governor to put that spring inside? If answer is yes can I use .090 nails to replace stock pins?

Really appreciate your help. I need to finish VB and I can install tranny in the car.

bbond105

I would install want ever spring the instructions call for. If they call for the original yellow spring install one, it won’t hurt if it is used. But bear in mind that the used spring may break sooner than a new spring. I think Sonnax sells original replacement springs.
It’s been awhile but IIRC the springs can be changed without disassembling the governor.
It’s been awhile but IIRC the springs can be changed without disassembling the governor.