Mountains Garage: TH400/ 4L80E Rear Servo Piston Set Up

[@stuartbuckley6113]

Thank you Shawn. I hope you have a great Labor day too!

[@jeremymcnicol9585]

Great video and I learned something. Keep this style of video coming for the new guys 👍

[@chiggyjiggy7019]

Currently rebuilding my th400 out of a 86 k20 and there's a washer that's shattered in the piston cup in the accumulator. Hopefully after a rebuild that's it. This channel is awesome.

[@the1andonly]

Thank you for posting. I bought an old truck that's been sitting for a while and just discovered that someone was probably in my transmission. The rear-low servo cover was missing two bolts, but they were in the pan. So at least thanks to your video I know what to check next. Hopefully the piston is still in there 🤔

[@CHEVYK10]

Appreciate this video And all the tips and tricks you give us.

[@GorhamWorks]

I really enjoy your approach and explanations. Great video sir!

[@markanderhalt1309]

Great info , Thanks, Have a great holiday

[@monkeywrenchization]

I put a good many of Transgo's kits in and they had an even different method a adjust the servo pin. In the kit were several washers, they want you to remove E clip and piston, and stack 8 washers on the pin, and re install piston. Now put piston/pin assy into the case and press down hard, the cover should rest against case. Remove washers on at a time until it sits flush, remove two additional washers.

[@christophersanders5007]

When I rebuilt my 4L80E I used the Sonnax adjustable pin. I installed the pin with no washers. All I did to test the adjustment was press the piston in 3/4 of the way to full seat, which caused the band to engauge enough that I could not turn the out put shaft by hand. Pushing the piston in all the way definitely put a grab on the direct drum.

[@johnsnyder4054]

Good info. , thank you, I have found d great success using the method that trans go uses in thier manual valvebody kit stacking washers till tight with cover then removing the correct amount of washers for your clearance , if I have washers left on pin at clearance I want I weld on pin that amount then reassemble . Works also on 4l80s . Everyone has thier own way of doing things this has worked for me for years and no expensive tools required just some machine washers

[@onenewworldmonkey]

After many hours of videos, I'm ready to put my tranny back together. How lucky I am to find your channel. I just subscribed. I've been babying my 4x4 truck for over a year after overheating the tranny. Meanwhile, I purchased another 4L80e from facebook for $150 and a manual. I contemplated just throwing it in but decided to look into it. (I should have just thrown it in). It looks like it is new inside. I even rigged up a vacuum guage and the valve body is like new. I decided at the very least new warner clutches were like $80 so I bought them along with OEM gaskets and seal kit. Then I was told that the sprags are the most common failures on a rebuild so I'm buying them tomorrow. I also bought a set of 7 Durabond bushings ("essential set") for $70 and a cheaper set of 13 for $30 and complete bushing driver set. I bent the thin return springs cage on my big press so purchased a cheap table top one for $30. This is my first transmission rebuild. I pulled my other truck tranny, pulled it apart in as big of packages as possible, set on a table beside the one I'm rebuilding, stuck up a poster of parts, put posted notes on all the components, and every day memorize the names of everything. I mention all of this because I feel you are the perfect person to run through how everything works. I replayed the part of this video of how you describe how the power runs maybe 5 times. I'm not rollerizing the output because I read a post from a guy whose roller bearing went bad. He said it sounded like a wheel bearing going bad. Also, this decision goes along with my mantra of simpler is better. I wasn't going to dual feed, then I was, then I wasn't, and probably wont. It does make sense to drill a few holes (pump body, cover, separator plate in 3 spots,direct drum, overdrive sprag, center support, and the case for reverse boost oil bulletin 264) Here are some recommended improvements I'm probably getting: Sonnax boost valve and wider stator bushing, 727 snap ring, thrust washers and bearings, wiring harness, and pistons. Here are some things I'm struggling with: Plastic silencer ring??? Torque Converter?? with little money I'm probably going ebay or Autozone. Heavy duty converter?? Here are some ideas: Why, where both the tranny lines go, arent the pressures measured and compared? I want an alarm that goes off when the two pressures differ (meaning a leak in radiator loop). This would save transmissions. Also, heat kills them so why isn't copper (twice the heat dissipation than aluminum) used through out the cooling? like copper fins on the pans. Sorry for so long. btw you can have any patent money. lol

[@onenewworldmonkey]

Forgot to mention that I wonder if I can program it to never go into overdrive when the button on the gear shifter is pushed for when towing.

[@nickkiofetzis5667]

well done shawn

[@terryrutch]

Great Job!

[@thomasryan2222]

thanks shawn great info...ironically i just welded up 50ish pins for 4l60e's cause the long pin is like 45 bucks and i hate the gold rings that transgo wants you to correct loose bands with... i do my own visual adjustment aswell even tho i have the j tool ...i used it once to confirm that its close enough and using the j tool on 4l60s is time consuming compared to a quick visual apply....i have a dozen or so videos to upload about 60s mostly for my customers about installs just have never been happy with how they came together

[@mistersniffer6838]

Wouldnt taking everything apart but the cup and rod, slamming the cup to the bottom, take measurement and just subtract 25 thou off suffice?

[@jimlesperance9051]

very informative. thank you

[@mikecochrane2074]

I'm curious. Why does this pin wear down. And how long should I expect my reverse to work properly in a newly rebuilt transmission? Thanks

[@chevyluv7216]

@Shawn what do you charge to rebuild a transmission?

[@TempoDrift1480]

So would you care to discuss the remedy for a banging into reverse? I ordered a Transgo kit that said it cushions the reverse and I wonder if you are familiar with that product and what it does. It appears to be a pin and several springs.

[@bags0153]

with the manual valve body modifications you made a video about do you need to do anything with the rear servo? of do you just put it back together like stock?

[@clashofclams19]

I took mine apart and the reverse servo gasket was a bit chewed up im having a problem with soft third gear shifts or sometimes wot in drive will get to a certain speed and seems like it pops into neutral im confused :(

[@gearheadted9210]

I like to neutral drop into reverse at 9,000 rpm,if she holds and fries the tires we good to go :)

[@onetransmission7871]

You missed the most important thing