No pressure rise

[tayto]

what servo are you running? what was your servo pin travel? what was 3-4 clutchpack clearance? what was your orfice size on 3rd feed and band release?

2-3 flare sounds like shift timing. hydraulics NOT tune. especially if the builder didn't pay attention to the things i mentioned above.

as far as pressure rise, need to get that figured out. if it's not going to full line pressure with plug disconnected and rpms @ 1500 rpm, need to start looking at pump.

@stutaeng that transgo plate defect was for a 4L80E FWIW.

 

[Bluechevy18]

running a corvette servo- has 1/16-1/8 travel and from what i remember the band clearance was good.. want to say clearance was in the the .070 area.. 3rd and band Release hole was drilled to .093 and 3/4 clutch is the z-pak and it was at .042 , i believe they call for a minimum .O50 and i couldn’t make it and knew most could get away with .030 so i left it at 0.042.. what would i be looking for besides broken parts, busted vanes, slides , pin , spring , making sure the bushing didn’t walk out/ get gauled up- inside the pump? And checking that the pump halves were centered?

 

[Bluechevy18]

Is it a 96? If so read this.

https://wiki.ad7zj.net/wiki/images/a/aa/2010-02-07_003951_no_2-3_upshift.pdf

It’sa 97.. it was one of the first things i checked but it was already fixed from the factory so it didn’t effect mine ( that i kno of) unless even the harness was pinched and grounded out it hurt the vcm before blowing a fuse. Then i wouldn’t kno were to start looking with that.

 

[tayto]

I would NOT use Z-pack, the stock borg warner high energy frictions are superior and if you want to go further raybestos gpz, but i have no experience with them only what I hear and for higher power levels. also run the gm nitrided or kolene steels here. it is what it is now, but in the future...

the corvette servo is mandatory on any build IMO. shift feel can be adjusted with orifice size and accumulator springs & piston stackup. i would have gone a bit smaller on band release myself. I personally like 0.100" 3rd feed and 0.082" band release if you are wanting "nice" shifts. you can peen the hole smaller with a steel checkball and redrill. 2nd feed i don't go much bigger than stock as it can hit hard if you go too big. i also block the 4th accumulator feed with a set screw, discard the piston and spring and drill 4th feed in the 0.093-.110" range. this also lubes the rear geartrain fulltime vs 4th only. DO NOT stack pistons like a certain hack on YouTube does. this kills lube to the rear geartrain in any gear.

Servo pin travel should be 0.060", no more than 0.075". 0.125" is TO much.

3/4 clutch clearance should be 0.15-0.030" range. I don't know about Zpack or how it will hold up with tighter specs than what they recommend.

As far as pump, the PR valve bore can be worn. This is why i made my own vac tester. Transgo makes a drop-in slightly oversized replacement, after that it needs to be reamed and oversized valve installed. I also prefer the Sonnax LB1 .490 boost valve over transgo .500. it has o-rings which fix internal leaks. With a healthy pump and Transgo .500 boost valve you should be making 200+ psi (usually 230 psi) with trans unplugged. I would not continue to drive on it until you get pressure rise. Slipping means clutches are burned.

 

[Bluechevy18]

Great info bud, i appriciate the input.. it does have the LB1 boost valve installed, also installed the 3 sonnax no-pin accumulators. All frictions are Borg EXCEPT 3/4 and hearing more about them makes me regret, but the first build they did the valve body and didn’t kno it was a rebuilt with over sized GM converter valve installed And changed it to a new standard size and it took all of 2 mins to fry the 3/4 so i had it replaced with the z-pak mainly because it was a 1 stop shop in a pack and thought having the 12 or15 (however many is in the z pak) would be beneficial over just having 6 frictions but i guess that’s not the case , the possibility it could have been drove for over 300 miles like this , i do have the slight smell of burnt fluid/clutch but there wasn’t much debris in the pan or filter, but while it’s out I’ll change the clutches
How many do you stack in the 3/4 with your borg? I seen ppl saying they can put 5-7 or maybe more. What’s the thickness of fiber/steels you stack for 3/4? And what’s the opinion nowadays on putting the springs for the clutches back in the input drum? Was told under 6k rpm can be left out and others say Always put them in… i just want a VERY RELIABLE -no hassle- that can handle 375-450hp that shifts smooth as butter and has no problem pulling roughly 3k pound trailer ever know and again

 

[stutaeng]

i just want a VERY RELIABLE -no hassle- that can handle 375-450hp that shifts smooth as butter and has no problem pulling roughly 3k pound trailer ever know and again

...I will just throw this out there, but have you considered a 4L80e swap? It's a very robust, reliable unit in stock form (GVWR = 15,000 lbs and GCWR = 22,000 lbs!)

I did a 4L80e swap on my 1500 and love it. Mind you, it was from a part-out special 2500HD truck with unknown mileage or service history. I decided to do the swap after buying my beater K3500 truck and realizing how buttery smooth the transmission shifts compared to old transmission on the 1500, and have since bought another 2500 SUV with the same transmission. I love the 4L80e!

As a bonus, the 4L80e rebuilds are pretty economical; not many hard parts to wear. No fancy (and expensive!) Sonnax "this and that" for everyday truck use. Some say they are overbuilt for a 1500, but I don't mind that at all in a transmission. Better overbuilt than underbuilt. Unless you are doing some crazy power like 600 HP+, stock units are just fine.

I keep recommending them here...I hope I don't get banned or anything.

 

[Caman96]

...I will just throw this out there, but have you considered a 4L80e swap? It's a very robust, reliable unit in stock form (GVWR = 15,000 lbs and GCWR = 22,000 lbs!)

I did a 4L80e swap on my 1500 and love it. Mind you, it was from a part-out special 2500HD truck with unknown mileage or service history. I decided to do the swap after buying my beater K3500 truck and realizing how buttery smooth the transmission shifts compared to old transmission on the 1500, and have since bought another 2500 SUV with the same transmission. I love the 4L80e!

As a bonus, the 4L80e rebuilds are pretty economical; not many hard parts to wear. No fancy (and expensive!) Sonnax "this and that" for everyday truck use. Some say they are overbuilt for a 1500, but I don't mind that at all in a transmission. Unless you are doing some crazy power like 600 HP+, stock units are just fine.

I keep recommending them here...I hope I don't get banned or anything.

I wish I had one. The truth hurts!

 

[tayto]

what is your power level? i have used stackups from a few "pro" builders. there are 2 camps: thick clutches and thinner steels and thick steels and thinner clutches. I have used the first camp with thinner steels with no problems. However, after information slurping from ls1tech I like the thought pattern behind thicker steels as they claim the steels help dissipate the heat better. Either way will be OK and ia more builder preference. You can run 6, 7 or 8 clutches. Apparently a 6 clutch stackup is good for 400-500 FWHP. I'm running 7 in a 700R4 I built about 9 years ago. Been in a 400fwhp caprice and now in my squarebody with about 325fwhp. All I've changed is fluid, torque converter and shift orifice size when it went into the truck. It probably would be fine fine with 6, but more gives some of us a warm and fuzzy, hahaha. Here are some stackups I have saved:

7 clutch:
.220 apply
7x.080 clutch
6x.076 steel
.220 pressure
.093 snap ring

.220 apply plate
7x.066 clutch
5x.100 steels
1x.078 steel
.198-.200 pressure


8 clutch:
.223 apply
8x.065 clutch
7x.077 steel
.157 pressure
.092 snap

 

[Bluechevy18]

Thanks for the list, helps with all the guess work . I have a 99 2500 with the 4l80 and it is SMOOTH, but i haven’t considered the swap.

I just figured i couldn’t feel or hear as much of the shift cause it’s a diesel. The 60 shifted great, just didn’t like the continuous in/ out in/ out lock up but after blocking the PWM i was happy with it. And no matter what i did, i could always feel a firmer shift to 3rd ,but it wasn’t a issue just more noticeable than other gears. Maybe the band release? Idk

Are they pretty much the same Internals as far as rebuilding? They the same length or did you have modify the drive shaft? Did you have to get a new/different pcm or can you program your existing one? Or is it as easy as wiring the harness up

And i dunno if i asked, but about my pressure issue, since it’s getting line pressure, wouldn’t that mean the pump is working? I don’t have experience/knowledge in torque converters so i dunno if that could effect anything with my pressure issue or not.

 

[stutaeng]

Thanks for the list, helps with all the guess work . I have a 99 2500 with the 4l80 and it is SMOOTH, but i haven’t considered the swap.

I just figured i couldn’t feel or hear as much of the shift cause it’s a diesel. The 60 shifted great, just didn’t like the continuous in/ out in/ out lock up but after blocking the PWM i was happy with it. And no matter what i did, i could always feel a firmer shift to 3rd ,but it wasn’t a issue just more noticeable than other gears. Maybe the band release? Idk

Are they pretty much the same Internals as far as rebuilding? They the same length or did you have modify the drive shaft? Did you have to get a new/different pcm or can you program your existing one? Or is it as easy as wiring the harness up

And i dunno if i asked, but about my pressure issue, since it’s getting line pressure, wouldn’t that mean the pump is working? I don’t have experience/knowledge in torque converters so i dunno if that could effect anything with my pressure issue or not.

Yeah, there was a thread here recently about trying to lock the TC on the 60e, but I believe the consensus was that it was not possible?

As far the 80e swap, it's not a direct swap, but too bad honestly. You need a different flex plate, shift the crossmember back, different yoke and reflash your tune/add new speed sensor back to the ECU. Depending on the year your swap is, one of the cooler lines needs to be extended a bit.

The 80 is longer. My swap was on a NBS ECSB 2wd, and no modification to the driveshaft was necessary; there's enough adjustment on the driveshaft center carrier mount on those trucks. I don't know about driveshaft on a GMT 400.

I don't know of anything internally shared between the 2 units. They are completely different machines. The 80 uses all clutch-to-clutch shifting. No bands for shifting. The only 2 bands inside are for reverse and engine braking.

Good luck.