I would try to throw that drum on a lathe and polish it first. If you can get it smooth again without turning, it will have a better outcome.
CK5
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Rebuilding My 4L80E Transmission
- Thread starter 1-ton
- Start date
That is probably what I am going to do. From the research I have done a new front planetary hubs are not available, but remanufactured ones are, and it looks like all they do is take a few thousands off on a lath then put new roller pins in the planetary if needed. There is a guy here in town that rebuilt my torque converter, and he also rebuilds transmission pumps by taking a few thousands of with a lath. I will take my front planetary to him to see if he can machine back to smooth for me.
That is true. The transmission whined all the time whether idling or in gear. I inspected the pump gears and vein ports, and it is in perfect condition. I have not pulled out any pump pressure valves yet. The torque converter is at a guys shop that is going to open it up to clean and inspect it. I also inspected the flex plate and rear crankshaft area, and it looks perfect as well.
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wasted wages
1 ton status
Input shaft would still be turning some internals, just not hydraulically coupled... not until clutch pack pistons and bands apply...would everything stop.
Which is why I asked about when it whines..
Some planetary's only turn at certain points of up shifting, or reverse...or when the band applys stopping the drum.
Powerglides were notorious for pinion issues under high horsepower applications, you had to unbraze the planet carrier from the shaft to access the pins to get the gears out. Drill or grind out the pins, replace all the parts with new and then mig the thing back together...
Aftermarket parts have made it easy to build powerglides that take 3000 hp on a pro tree brake and still survive..
Which is why I asked about when it whines..
Some planetary's only turn at certain points of up shifting, or reverse...or when the band applys stopping the drum.
Powerglides were notorious for pinion issues under high horsepower applications, you had to unbraze the planet carrier from the shaft to access the pins to get the gears out. Drill or grind out the pins, replace all the parts with new and then mig the thing back together...
Aftermarket parts have made it easy to build powerglides that take 3000 hp on a pro tree brake and still survive..
Since my transmission whined all the time after it warmed up, I need to concentrate on the flex plate, torque converter, and pump area to find the problem.
Well you're already having the converter done. Have you taken the pump apart? Some shops sell rebuilt ones ready to drop in, if it will be stock. Although your super early model could have some difference.
I believe it's possible to get some whine from a good pump that's working at high pressure. It's possible a valve is stuck or bore worn. This may be more of an @Greg Ducato level question.
Have you cut the filter apart? If it's restricted, that's effectively more pressure drop across the pump, even if the line pressure is normal. It doesn't say if you tried a filter change before pulling the trans out. How did the magnet look? If the band/drum wear isn't built up there, it must be in the filter.
I believe it's possible to get some whine from a good pump that's working at high pressure. It's possible a valve is stuck or bore worn. This may be more of an @Greg Ducato level question.
Have you cut the filter apart? If it's restricted, that's effectively more pressure drop across the pump, even if the line pressure is normal. It doesn't say if you tried a filter change before pulling the trans out. How did the magnet look? If the band/drum wear isn't built up there, it must be in the filter.
I took the pump halves apart and they look perfect. I even had the guy who built my torque converter and rebuilds pumps look at my pump, and he said the thing looks perfect. The only thing I have not taken apart on the pump to inspect (yet) is the pressure control valves. I have Sonnax pressure control bleed off pressure valves in it, but I still need to inspect them.
I could go on forever on the little details I have learned about my early model 4L80E, but no one has t6he time for that. You are correct that my early model pump has some small differences compared to later model pumps. @Greg Ducato may not have the time to respond to every little item on this build. I have seen many transmission experts get chased away from forums by idiots wanting to argue over every response they make.
One screw up I have on my transmission is that I have an SFI rated flex plate designed for T400 and T350 transmissions that does not have the correct off-set 6-bolt pattern for 4L80E transmission torque converters. I am going to get the correct flex plate for this transmission. I also am going to look into the crank shaft to torque converter coupling clearance. My engine is a brand new crate engine the crank shaft is perfect, but the torque converter is the factory original. I am going to see if a shim sleeve is needed to make the torque converter to crankshaft mating perfect.
I took apart and inspected the forward drum and direct drum today. They both looked good. The piston seals looked a little dry and brittle. Most of the clutches looked good. I am using a video from transmissionbench.com. Because this is my first automatic transmission build, I am following it step-by-step, and not trying rush anything by jumping around from one step to the other.
Using my 20-ton press to Depress the spring cage on my forward drum, in order to get the spring cage retaining snap ring off.
Using my 20-ton press to Depress the spring cage on my forward drum, in order to get the spring cage retaining snap ring off.
wasted wages
1 ton status
I've made depressors before using a large pvc cap, cut some slots in the sides, drill a hole thru the top and ran a piece of 3/8 allthread thru the center...
Put a piece of flat bar on the bottom of the clutch pack and tighten it down...
Keeps everything nice and caged..
Put a piece of flat bar on the bottom of the clutch pack and tighten it down...
Keeps everything nice and caged..
I finished the tear down and inspection of the center support, and the rear output planetaries. This completes the tear down and inspection of the transmission internal parts. The next step is cleaning and reassembling. So far everything looks good. The only problem was the rear output planetary reverse drum needs to be turned smooth on a lath. I have not inspected the pump pressure valves, but the pump body itself is in perfect condition.
The center support, rear output planetaries, and reverse band.
The center support, rear output planetaries, and reverse band.
Looks like good work there. Long live us DIYers.
Back to the beginning...you pulled the accessory belt(s) and/or unbolted the torque converter to verify noise source? Or was it stethoscope or similar?
I thought you said fluid looked good. Where is the wear material from band/drum?
Back to the beginning...you pulled the accessory belt(s) and/or unbolted the torque converter to verify noise source? Or was it stethoscope or similar?
I thought you said fluid looked good. Where is the wear material from band/drum?
I used a stethoscope to locate the whining sound. It sounded like it was coming from the torque converter/pump/or just behind the pump. Fluid was in good condition. I did find a small amount of steel stuck to the rear speed sensor magnet where the rear output planateries and reverse band are located. Nothing was stuck to the front speed sensor magnet. A small amount of steel was stuck to the pan magnet, but it was a very small amount.
No, I never did do that. I do not have the tool for that, but I will probably get one to check pressures when the transmission is back together. The whining noise coming from the transmission could be heard even without my stethoscope. Once the whining would start after the fluid got hot I could hear it just standing next to my truck coming from the transmission torque converter area. If the torque converter is not the problem then there is a possibility that a pump pressure valve got stuck. A pressure reading would have been good for diagnosing that. I will get to pulling the pump pressure valves soon.
Got the center support done today. I got the new piston seals in and sealing rings. I left the second sealing ring off because I am going to internally dual feed my 4L80E transmission, in order to do that the second sealing ring on the center support needs to be left off. I also installed a hardened steel plate on the spring cage that comes with the Jakes Performance Stage II kit. The stock spring cage retainers are made of a soft steel, and the direct drum can dig into them causing problems. My spring gage retainer did not show a lot of galling, but the was some. Jake has a video where he shows center support spring cage retainers are torn all to hell.
Center support reassembled with new piston seals, sealing rings, and hardened steel spring cage retaining plate from jakes Performance.
Center support reassembled with new piston seals, sealing rings, and hardened steel spring cage retaining plate from jakes Performance.
Did you replace the bushing in that center support? If not you should consider it, it more or less supports the direct drum via the sun gear shaft. Also, if you plan to machine the reverse band apply area use the correct style band for the finish you obtain and lengthen the band apply pin as needed for correct clearance.
I would rather have a high quality OE flexplate than an SFI all things considered, especially with 6 bolts on the converter.
I would rather have a high quality OE flexplate than an SFI all things considered, especially with 6 bolts on the converter.
wasted wages
1 ton status
Thanks for posting that Greg,,, it confirms my suspicion that a sagging geartrain could be causing the whine... the spur gears carrying weight from worn bushings is No Bueno....
My center support bushing looks almost new even though I do have a complete new bushing kit with my rebuild kit. All of the bushings look new, which surprised me. I think someone may have had this transmission rebuilt just before I bought this truck. The transmission has a sticker on it saying it is a GM Service Replacement Transmission from 1993 that was probably replaced under warranty, but all the seals and bushings look so new I think it was rebuilt again sometime before I bought the truck.
When it comes to reverse bands I think there are only two types...the late model type smooth one, and the grooved type early model one I have in my rebuild kit for my early model 4L80E. I have already bought a stock replacement 6-bolt flex plate for my 4L80E transmission. I have also ordered a Sonnax adjustable rear servo pin. It is due to be shipped out to me in a couple of weeks.
When it comes to those rear output planetary drums reverse brake band surface being worn out what do you do when it comes to that? Do you have it machined, or buy a rebuilt one. If you have it machined do you have somebody in your area that does that, or where do you go to buy a rebuilt one? The planetary gears on this drum are in good shape they spin smoothly, and the side play is .016...well within specs.
We clean up the reverse drum on a lathe, taking off the high spots and polishing it for use with the later band, good move on the Sonnax servo pin
