CK5
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Rebuilding My 4L80E Transmission
- Thread starter 1-ton
- Start date
Got the pump, overdrive planetary/housing, forward drum, and direct drum out today. So far I cannot find anything wrong. All the bushing are in good condition, and their contact surfaces are good. The only thing I found so far are some clutch bands that look a little thin from high milage. Even though my transmission functioned fine, there was a whining sound starting to develop. I used my stethoscope to try to locate it, and it sounded like it was coming from the overdrive area just behind the pump.
That sounds like a bench job. Some shops do not like doing a bench job because when the install goes wrong they blame the shop that put the transmission together. The price I was quoting was taking the vehicle in to do the whole job. I want to do my own transmission because there are known problems that the early model 4L80E transmissions had. I have done a lot of research on this, and intend to fix them. I would not trust any transmission shop to know or care what these known problems where, or to bother wanting to fix them.
I am following along because I need to rebuild a 1991 version as well...
That's me taking the vehicle to him and he does it all. I trust him fully. He's done 4 in the past for me and a few more for friends and family. If there's a problem or trick to know about em, he knows it.
When your transmission builder says increasing "800 HP" they actually mean 800 -foot pound torque. They are doing that by installing a billit forward clutch hub. That only applies to the early model 4L80E transmission, which came with a cast iron forward clutch hub. The later models in 2001 changed to a billit one from the factory. $3000 is cheap when labor is factored in. I do not trust anyone to work on my rare 1991 V3500 Crew Cab. If I handed over the keys to any shop to a truck like mine they would steal it because there is way more money in stealing a truck like mine than there is in fixing it.That's me taking the vehicle to him and he does it all. I trust him fully. He's done 4 in the past for me and a few more for friends and family. If there's a problem or trick to know about em, he knows it.
My transmission is actually a 1993 version 4L80E that was installed under warranty by the original owner many years back, but is still an early model version of the 4L80E. The odd problem with the first year 1991 version of the 4L80E was the "temp switch" they came with in the valve body. When you buy a internal wiring harness they are an updated version only, which does not come with a temp switch terminal end. When you buy an updated wiring harness you have to update the female end of the wiring harness. Most new internal wiring harness will come with all the female end kit to update it.
Where I live I don't have to worry about the shops and such. Definitely not my vehicle coming up missing. It's just not like that around here.
The trans I'm having built and put in my truck is an 05. So it should have the good hub, and does have the better fluid return path. Originally I was going to just have the 95 in it done.
My other 1 is a 96 4x4 model going in my 81 crew.
Any special tools needed for a project like that? Besides the stand/mount to hold it vertical.
The trans I'm having built and put in my truck is an 05. So it should have the good hub, and does have the better fluid return path. Originally I was going to just have the 95 in it done.
My other 1 is a 96 4x4 model going in my 81 crew.
Any special tools needed for a project like that? Besides the stand/mount to hold it vertical.
I got the intermediate clutch pack, center support, and tail shaft assembly out today. The transmission case is completely gutted now. I still have not found anything obviously wrong with it yet. Everything so far seems to be in excellent condition like the transmission has hardly any use at all. The next step is start tearing down all the individual componets for inspection.
If you buy one of those transmission bench stands you have to buy an adapter for about $20 for it to work on a 4L80E case. Another tool is a drum clutch spring compressor tool. I do not have one because I am going to use my 20-Ton press to lightly compress the drum clutch springs, in order to remove the snap rings. I just have to take a flat piece of steel, and bend it into a U shape that is the correct width.
On the 4r75e video from Transmission Bench he shows how to build a clutch spring compressor from wood for guys that need to go that route.
Other than some big snap ring pliers I have basically no transmission tools, yet I've done a number of them. I usually fabricate my way through, but what's a few more hours in a 1-off job compared to web searching, ordering and waiting for tools compared to getting it done today?
My best trick, that I wish was patentable, is to wrap Teflon seals with tightly stretched electrical tape, instead of buying all the custom seal sizer tools.
Best advise is to have shelves or tables to lay all the parts out on, as per whatever manual you're following. Inevitably, you'll scratch your head over something, so best to minimize that. Any simple question or mistake can cost hours to days to correct.
10-4 on that one. The one thing I bought for this job was a steel work bench to lay out all the parts, and mount my transmission bench stand to.
The first few I built I didn't have a stand, you can cut a hole in a bench or make a stand out of some pipe and plate.
Then I would just lay it on the back side after the the pump was on.
Then I would just lay it on the back side after the the pump was on.
Disassembled my pump and over run clutch/planetary assembly. I have have paperwork that shows the transmission was replaced under warranty back in 1993. So far I cannot find anything wrong with my transmission. My 4L80E transmission looks so good it looks like somebody rebuilt the thing just before I bought this truck over 20-years ago. I hope I find something wrong with it because it was whining pretty good after it got warmed up, but it still functioned properly. I just wanted to fix what ever is wrong with it before it burned itself up.
Here is a picture of how I am depressing my spring cage in my drums. I just bend a piece of steel in a U shape, and then use my 2-ton press lightly to depress it, in order to remove the snap rings.
Here is a picture of how I am depressing my spring cage in my drums. I just bend a piece of steel in a U shape, and then use my 2-ton press lightly to depress it, in order to remove the snap rings.
wasted wages
1 ton status
If it was a whine, I'd look over the planet gears and the fit to the shaft..IE: gear mesh.
Any wear on clutch pack or case bushings is suspect, out of round or worn bushings cause the entire internal assembly to sag throwing off alignment and cause the planetaries to bear the weight.. even the pins in the planetary gears need to be checked for looseness and end play..
Front pump is another source of gear whine..
Critical inspection of the stator shaft and
pump gear tangs, gear mesh and wear.
Also send the TC out to be rebuilt by a reputable shop.
Did it whine at idle in park?
Or just as it went up thru the gears ?
Any wear on clutch pack or case bushings is suspect, out of round or worn bushings cause the entire internal assembly to sag throwing off alignment and cause the planetaries to bear the weight.. even the pins in the planetary gears need to be checked for looseness and end play..
Front pump is another source of gear whine..
Critical inspection of the stator shaft and
pump gear tangs, gear mesh and wear.
Also send the TC out to be rebuilt by a reputable shop.
Did it whine at idle in park?
Or just as it went up thru the gears ?
I believe I have found the problem with my transmission. The reverse servo pin was not adjusted correctly, and it was holding my reverse band up against the front planetary drum. This created drag and heat build up on my transmission. The front planetary drum is tore up some, and the reverse band has friction material worn down on the thin side. A new reverse band came with my rebuild kit, and I am going to have to buy a front planetary drum. Front planetary drums are hard to find. I have seen some rebuilt ones that I think the reverse band surface is lathed down 10-thousand or so.
It whined all the time after the transmission warmed up. Think I found the problem though.
