4L80E & TH400 Tech.

[Jrgunn5150]

Originally Posted by clinebarger

All GM Output VSS sensors create the same 40 Pulses Per Revolution A/C Sine Wave Signal.

Perfect! That's what I needed to know, thank you.

[jimmyjammoto]

Originally Posted by clinebarger

Both NP241, NP261 have a VSS sensor, So no need for you to buy a 2wd unit. A 4wd unit & Adapter will fit both T-Cases.

We only use 2wd units when adapting a older T-case that doesn't have a Output VSS sensor.

All GM Output VSS sensors create the same 40 Pulses Per Revolution A/C Sine Wave Signal.

So running a 5.3 / 2WD 4l80e mated with a NP208 (no vss) would allow everything to work properly in 4LO?

[Dustytrix]

Subed for reference.

[softballnrd27]

Not sure if you covered this or not but what is the best way(right way) to convert from the bolt on yoke to a slip yoke on a 1998 4l80e? I ordered a a slip yoke that fits the trans but it doesn't seem like it allows enough slip.

[clinebarger]

Originally Posted by softballnrd27

Not sure if you covered this or not but what is the best way(right way) to convert from the bolt on yoke to a slip yoke on a 1998 4l80e? I ordered a a slip yoke that fits the trans but it doesn't seem like it allows enough slip.

I have not......

The easiest thing to do is run a short "Counter Bored" Yoke, http://www.sonnax.com/parts/3841-slip-yoke

The "Correct" way & a Must for vehicles with a lot of suspension travel is to machine off the O-ring boss & run a long full spline Yoke.

The "Best" thing to do.....Buy a Core with a Full Splined Output Shaft to start with.

[rickpilgrim]

Clinebager, thanks for all your help on the forum here!

We've been going through 4L80E's like cookies at a bake sale on one of our trucks. Doesn't matter if they are rebuilt by Movarus, Good wrench , local shop or junkyard. I only am given a 90 day warranty on these as it's a snow plow(commercial) truck.
We have no check engine light, nothing shows up on the Verus, I have a pile of 2500 mi or less trans coolers and lines plus three new radiators installed to get any warranty. All of them have good line pressure when installed but in a few miles you notice it take longer to engauge first or reverse but still have clean fluid, another 500 mi or so you start to get soft shifts and some flaring between shifts, new fluid and filter and line pressure is 10-16 psi lower and soon the slipping in 1/2/r is very noticeable and we stop running it.
98 K2500 reg cab long box 5.7 powered truck.
We and dealer think it's an ecm/wiring Janessa problem, do you have any ideas?

[clinebarger]

I would like to tear one of them down to see exactly what's failing, Maybe I can walk you through it???

The change in line pressure has me concerned, Using a DVOM set to AMP scale, Connect one of the leads to the each of the Pressure Control Solenoid wires.

Pin 6 of the Clear connector is the PC High control
Pin 16 of the clear connector is the PC Low control

Use your scanner to monitor the Commanded Amp's......It should match the Actual output read by the DVOM. If it's off (Especially higher Amp's).....The PCM is faulty or You have a bad ground.

These transmissions may be eating pumps for some reason.....Like engine/trans alignment issues, Are both dowels present & in good shape??
Flexplate runout?
Inspect the pump gears, pump bushing, & pump body for wear/damage.

Check the Boost Valve Sleeve for being loose in the bore, The will cause Torque Signal oil to leak & cause low line pressure when the unit is hot.
Same with a loose Pressure Regulator Valve.

4L80E Reverse Bands are not suitable for plowing duty, Use a TH400 "Grooved" Band.

Check the Forward Drum for damage where the Input Shaft & seals ride, VERY commonly over-looked & will cause repeat Forward Clutch failure.

Use Raybestos grooved HD frictions in commercial applications (Forward, Intermediate, Directs)

Do not use 4 frictions in the Intermediate Clutch, Use 3 TH400 frictions, Wave Plate, Steels & Backing Plate. The 4 friction set-up is great for holding power BUT no so much for a HD set-up.

Set your end-play correctly!!!!! TH400/4L80E will beat themselves to death with to much end-play, Very quickly in a plow truck that is shifted from forward to reverse a million more times than a regular truck.
http://www.sonnax.com/articles/408-p...-train-failure

[rickpilgrim]

Thanks for the tips- I really appreciate them! Have made a copy to pass on to my new Trans guy for my 2002 GMC k2500 trans this summer. We don't rebuild our own due to time, either buy reman or send out.
Wish you had a shop here!
Thanks Again!

[rickpilgrim]

Thanks for the tips- I really appreciate them! Have made a copy to pass on to my new Trans guy for my 2002 GMC k2500 trans this summer. We don't rebuild our own due to time, either buy reman or send out.
Wish you had a shop here!
Thanks Again!

[indymachinist]

Awesome thread. Just awesome. I look forward to using it when I rebuild my old 93 4l80e.

Thanks clinebarger for the effort you put into this!

[frankslagoon]

You probably covered this somewhere in here but I'll ask again.
I just put a 4L80 from a 2002 van behind a gen 1 327.
the van had a 350 vortex in it. fluid was good so I just put a filter and fluid in and crossed my fingers.
Everything worked good when I fired her up. upshifts and downshifts in drive all good. Then when the controller ( Quickshift 1) shows 140 F. the convertor starts locken up and killen the engine. worse in reverse but still bad in fward.
I put a temp gauge in the test hole on drivers side of tranny. the gauge takes 30 minutes to come up to 100 F. but the controller says I'm at 140 F. I checked the gauge and sending unit on my engine temp system they are working. The tranny is plumbed into the rad. but did have a little trouble getten the lines in close enough to the tranny so they don't hit the tunnel.
I don't have any trouble at 130 F. but then it starts grabbing real hard above that. this is my first electric lock up tranny, but I've rebuilt some TH. in the past. ???

[clinebarger]

The Cooler Circuit is routed to the Converter first to keep the TCC Off & Charge the Converter.
If this circuit does not have the correct volume, The TCC will drag and/or lock-up & kill the engine.

This is caused buy 1 of 2 things.....

1. Worn out pump, PR Valve Bore, or End Plug leak..... As the fluid heats up, Pressure & Volume drop, The Pressure Regulator Valve will put a priority over the Cooler Circuit to maintain Line Pressure, The symptoms will happen at idle because that's when the pump is least efficient.

2. EPC "amps" to low at idle, (To much pressure demand), Amps should hover right around 1.00 at idle. Have you "Learned" the TPS value on the controller?? The controller must know where closed throttle/idle is!

To low of a curb idle can also cause this.

[frankslagoon]

I did set the TPS up it's a pretty nice holley product designd for the electric choke on the carb. low idle shows .54 volts h. idle is 4.40. I'm not sure how to check the amps. I,m pretty sure I can turn the voltage up if that's what your talkin about. Does the fact that I don't get good temp readings at the test outlet mean anything

[frankslagoon]

So I'm doin some more homework.
seems like if the pump and or
pr valve was weak or to many bleed of spots that increasing pressure with RPMs would bring the convertor out of lock up. But if the EPC sol. is screwed up or the cooler line is restricted that the thinner the fluid get the quicker the PR valve will lock up the convertor. Am I thinkin in the right direction ? I don't like replacen parts till I understand why I'm replacen them.

[indymachinist]

Hey clinebarger

As I posted the other day I got ahold of a cheap '93 4l80e that was taken in as a supposedly working core. (I bought it from a retired trans builder that had it left laying around) Even though it supposedly works, I am going to assume it needs a rebuild to be "right."

I am going to use this in a turbo LS swapped C10. It will have a max of about 800hp but more realistically around 4-500 horsepower for street cruising.

I know the 800hp is pushing it pretty hard on the input shaft and forward clutch hub. I also know this trans still has the old outdated harness and case connector so it likely has never been opened up. Sounds like the 93 is good that it has the larger overdrive roller clutch but bad that it also has a 16 element intermediate sprag.

So it sounds like I need to upgrade the wiring harness and the intermediate sprag for sure. Probably the input shaft and forward hub also? Who do you go to for good rebuild kits? I have been looking at the rebuild kits from Jake's Performance either stage 2 or stage 3.

http://www.jakesperformance.com/rebuild-kits/

The price seems fairy steep but maybe not too bad once you add up all the little things this trans probably needs anyways to be brought up to spec. What do you suggest?

[indymachinist]

I should add I have never rebuilt a transmission before but I'm a machinist for a day job so I am familiar with all of the various measuring tools and how to use them. Sounds like that is a lot of the job.

Also, I haven't even taken the pan off to check the magnet or get a general status check on this transmission. I do know it had fluid in it when I picked it up and it was red and not burned smelling.

[dfarr67]

Thanks, do I rebuild what I have or is there any merit going with the earlier gun drilled shafts with a different lube circuit? Not racing just a nice meduim duty towing/4x4/street build behind a torquey 385 TPI.

[dfarr67]

A few other questions as well.

- My mechanic has had to replace a few trans alum oil cooler lines on newer GM trucks as the crimps let go on the rubber hose portions. My truck is a 1989 K1500 with 700r4- would I order 1998 K2500 454 lines (are these steel?), or make my own, my oem steel lines never gave me any trouble.

- Regarding frictions are all HE created equal or try to find BW rather than Alto or Raybestos?

[clinebarger]

The larger O/D Roller Clutch requires a matching O/D Carrier & Overrun Hub.

The trick with a small O/D Roller Clutch is to not Hammer it with the shifter in D4/OD, Put the trans in D3/3rd, This brings on the Overrun Clutch & helps support the Roller Clutch.

Those fitting work fine, We use them on 3rd & 4th Gen Camaros all the time, But you can use straight fittings in a Truck.

Are you inquiring about the AFL Valve Bore repair?

[dfarr67]

Originally Posted by clinebarger

The larger O/D Roller Clutch requires a matching O/D Carrier & Overrun Hub.

The trick with a small O/D Roller Clutch is to not Hammer it with the shifter in D4/OD, Put the trans in D3/3rd, This brings on the Overrun Clutch & helps support the Roller Clutch.

Those fitting work fine, We use them on 3rd & 4th Gen Camaros all the time, But you can use straight fittings in a Truck.

Are you inquiring about the AFL Valve Bore repair?

Yes to AFL repair- depending on how bad shipping would be, I think it would worth it. Also any updates to the valve body and a new plate. Would the larger clutch be a worthwhile upgrade- could you supply all parts needed so I don't order wrong pieces.

Alto has screwed me to many times with their JUNK

Can you enlighten me to this warranty logic- Alto just lost future sales of not only you but anybody reading this- it's not like there's no competing product out there.

What do you think of this pan? I'm not happy with extra welds/potential leaks, but can't see paying big dollars for a cast pan. I understand these are heavy guage- too bad they don't offer a version sans tubes.

https://www.amazon.ca/Derale-14207-T...keywords=4l80e

[dfarr67]

Moving to the front end of the trans- I'm thinking of a reman'd 200ish Express van 4.3L toque converter- how would this behave with a 383?

[picklito]

What's the opinion on Torlon check balls vs steel? Do they save wear on the plate, and do they last?

[clinebarger]

Originally Posted by picklito

What's the opinion on Torlon check balls vs steel? Do they save wear on the plate, and do they last?

The do not damage the plate, The seal really well, But.....They will wear down & pass through the plate eventually.

The trick is to angle/chamfer the edge of the holes the balls seat against on the plate, Some Emroy cloth on the end of a push rod works well.

[clinebarger]

I missed dfarr67 last 2 post.......I have the Sonnax AFL repair tools, But my own testing has proven that the Trans Go repair is adequate.

A stock pan is fine, Spend your money on a good cooler!

Buy a quality converter!!!!! Circle D, Precision, Jake's, North Texas converter, Yank etc.........

[dfarr67]

Originally Posted by clinebarger

I missed dfarr67 last 2 post.......I have the Sonnax AFL repair tools, But my own testing has proven that the Trans Go repair is adequate.

A stock pan is fine, Spend your money on a good cooler!

Buy a quality converter!!!!! Circle D, Precision, Jake's, North Texas converter, Yank etc.........

Does the Transgo valve have redesigned lands so as to not wear as quickly?

I looked into Circle-D and I had to go billet$$ for SBC gen1 flexplate otherwise he did have a reasonably priced non billet GM unit I couldn't use.