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The Shop Truck

1971 Chevy C20 with a custom flat bed.
Overview Gallery Discussion
Well, the transmission is apart for the most part. Here is what I think was the cause of my transmission problems.
IMG_20260919_111703046.jpg

That is how the Lokar locking 4l80e dipstick installed out of the box... This is how it should have been (1/4" above the sealing surface).
IMG_20260919_112434561.jpg

I've only got the 2nd and 3rd gear clutches pulled right now, but they're both fried. I need to pull everything else apart too, but I'll get to that later.
2nd gear (intermediate clutches). Some of the steels are very warped.
IMG_20260919_133511761.jpg

3rd gear (direct clutches). The base plate is cone shaped, I don't think it's supposed to be, pretty sure that's the turbo 400 plate which eliminates the wave plate. @folkenheath is that supposed to be flat?
IMG_20260919_135225377.jpg


Gearstar told me I didn't need to do any modifications to the drum to install the trans brake, but there's supposed to be a .063" hole drilled in the direct drum that isn't there, so I think they were wrong.
 
If the trans came with the dipstick, are they going to warranty anything?
 
It did not come with a dipstick, I added that.
More damage, 1st gear got hot too, but not as bad as 2nd and 3rd. Forward clutches:
IMG_20260919_150342165.jpg

When I pulled the input/turbine shaft it pulled the forward drum out with it, because the end of the output shaft was slightly mushroomed. I need to figure out what caused that and if I need to replace the 300M $haft or not.
IMG_20260919_150336693.jpg

I've got a lot of questions, and nobody to answer them until Monday...
 
I know Heath rebuilt his 4L80, but I'm not sure about anyone that's doing it for a living.
 
I didn't use any wave plates, and I think you are correct every clutch seems to have gotten way too hot from slipping, in fact I am surprised it lasted as long as it did.

Looks like you need at least all new steels and frictions and possibly seals if they got hot, I don't know what else. And yes drill the bleed hole and swap the springs for the Tbrake.

I have no idea on that mushroomed shaft, it seems as if there wasn't enough endplay or something? I remember checking endplay in both the front and rear of the center support, but I don't know what would happen if it was too tight, its been 15 years since I did mine, it probably needs a refresh when I build one for the Blazer.
 
folkenheath said:
I didn't use any wave plates, and I think you are correct every clutch seems to have gotten way too hot from slipping, in fact I am surprised it lasted as long as it did.

Looks like you need at least all new steels and frictions and possibly seals if they got hot, I don't know what else. And yes drill the bleed hole and swap the springs for the Tbrake.

I have no idea on that mushroomed shaft, it seems as if there wasn't enough endplay or something? I remember checking endplay in both the front and rear of the center support, but I don't know what would happen if it was too tight, its been 15 years since I did mine, it probably needs a refresh when I build one for the Blazer.
Click to expand...
From what I was seeing online, all of the damage, including the shaft galling can be explained by loss of pressure. If they're not supposed to touch under normal conditions then I can't imagine it matters that they're galled.
 
If the end is galled probably no big deal, but didn't you say it was mushroomed? That area has two sealing grooves on it, may not need replaced but maybe touched up on a lathe?
 
folkenheath said:
If the end is galled probably no big deal, but didn't you say it was mushroomed? That area has two sealing grooves on it, may not need replaced but maybe touched up on a lathe?
Click to expand...
When I took the transmission apart everything that was on the mid shaft pulled out as one unit. I had to google why that happened and that's where I saw the term "mushroomed". The end is just galled and pushed a tiny bit of metal into the spline area so it couldn't be pulled through the splines. It just took a few light taps with a brass drift to push the metal out of the splines and get it apart. A little work with a file on the splines is all it needs.
 
I'm a bit frustrated with Gearstar at this point. I've been trying to get them to ship me the parts I need since Monday and they haven't even figured out exactly what I need yet. I talked to their shop manager again today, I'm going to have to replace the turbine $haft and the forward drum as well as all the clutches and steels etc. etc.
The most I've gotten them to commit to is that it will ship "next week".
All because of a ****ing dipstick.
 
Well, Gearstar got back on my good side this morning. They called at 5:45 and left a message (I was still asleep and the phone was on DND). They have all my parts ready to ship and they're sending them to me for free. I didn't ask why, but that's what they're doing. They don't own Lokar, but they are an authorized dealer and do work closely with them, so that may have something to do with it.
They even offered to have me ship the converter to them and they'd cut and clean it for free. I don't know as I need that as the pump was clean when I took it apart, also I don't want to have to pay and wait for shipping a heavy ass converter to Ohio and back. I have been slowly sucking all the fluid out of it for the last few days (it's a slow process).
 
Just wondering, but even being a 4l80 dipstick,... Doesn't Lokar specify in the directions to adjust level/length on first install?
When I was looking up adjustment for my elcheapo, the Lokar directions were what came up.

Personally, I want to go back to the stock one.
It's ugly, but easier to read lol.
 
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