80E no reverse ?
I have many many thoughts on this.
I bought a '92 siverado dually with no trans, then I found a 1999 or 2000 OBS silverado 3500HD with 60,000 miles on it. It was a stolen recovery so there was no test drive.
I put that 4L80E in my truck and it worked great but had weak to no reverse.
I asked a lot of reputable trans builders online and no one had an answer, I also asked a lot of local guys, everyone had all kinds of suggestions on where to look and what could cause the problem, but my trans had none of the problems.
So I took it apart for a rebuild and found nothing really wrong with anything that had to do with reverse.
Now one guy showed me a case that had a blown out worm track in it caused by high pressure, the boost valve sticks in these and causes this.
I connected a gauge to it and got over 500 psi at 2000 rpm in reverse.
Thought that must be the problem, dropped the valve body and checked, no cracks. So just for the hell of it I took an air chuck and applied the reverse servo with it.
I thought it worked at first because there was a bang when it applied. I took it out and found that the bang was the servo bottoming out in the bore.
I could tell because the servo was beat up around the edges.
So I welded the tip of the apply pin and grinded it down to where it was about 1/8" longer, put it back together and it had reverse!
For a little while....eventually the servo broke where it was hitting the case before.
GM wanted $45 for the servo piston only and it wasn't in stock. I had it apart so I needed it, called the local trans hardpart supplier and they wanted $40 for the whole assembly. Got lucky too because the apply pin that came with it was longer, it was about as long as I had made mine, had a 2002 casting clock date on the piston.
During the rebuild I also replaced the boost valve with a Sonnax pressure limiting boost valve that prevents high pressure.
So you should get the pressure checked. The one trans guy with the case also showed me a direct drum that blew apart because of high pressure problems. It can also break reverse bands, blow out seals, etc.
I don't know how far into this trans you plan to go on your own but if you tear into it I can tell you more of what to look for.
I bought a '92 siverado dually with no trans, then I found a 1999 or 2000 OBS silverado 3500HD with 60,000 miles on it. It was a stolen recovery so there was no test drive.
I put that 4L80E in my truck and it worked great but had weak to no reverse.
I asked a lot of reputable trans builders online and no one had an answer, I also asked a lot of local guys, everyone had all kinds of suggestions on where to look and what could cause the problem, but my trans had none of the problems.
So I took it apart for a rebuild and found nothing really wrong with anything that had to do with reverse.
Now one guy showed me a case that had a blown out worm track in it caused by high pressure, the boost valve sticks in these and causes this.
I connected a gauge to it and got over 500 psi at 2000 rpm in reverse.
Thought that must be the problem, dropped the valve body and checked, no cracks. So just for the hell of it I took an air chuck and applied the reverse servo with it.
I thought it worked at first because there was a bang when it applied. I took it out and found that the bang was the servo bottoming out in the bore.
I could tell because the servo was beat up around the edges.
So I welded the tip of the apply pin and grinded it down to where it was about 1/8" longer, put it back together and it had reverse!
For a little while....eventually the servo broke where it was hitting the case before.
GM wanted $45 for the servo piston only and it wasn't in stock. I had it apart so I needed it, called the local trans hardpart supplier and they wanted $40 for the whole assembly. Got lucky too because the apply pin that came with it was longer, it was about as long as I had made mine, had a 2002 casting clock date on the piston.
During the rebuild I also replaced the boost valve with a Sonnax pressure limiting boost valve that prevents high pressure.
So you should get the pressure checked. The one trans guy with the case also showed me a direct drum that blew apart because of high pressure problems. It can also break reverse bands, blow out seals, etc.
I don't know how far into this trans you plan to go on your own but if you tear into it I can tell you more of what to look for.
we want to sell it but who wants a truck with out reverse.
Hell I bought mine with 201,000 and NO transmission, had it towed home. If the price is right, people will buy. Mine was an old roofing company truck, tar everywhere. I cleaned it all up, wish I had before and after interior pics. Only interior part I replaced was the head liner.
Everyone thought I was crazy when I got it, when I was done no one could believe what I did to it.
Here are some pictures.
BTW it had a W/T grill but it was a Silverado. And it was originally black.
Paid $2500 for it.
