I may have finally had that epiphany

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So, I just returned home from the auto parts store and tried again, to no avail, to put my transmission in reverse....nothing... so I did as any normal genius would do, I revved the engine a little bit and.... still nothing.... or was it nothing? Wait a minute, put it in neutral, rev the engine a little again.... there it is again.... a very noticeable, frankly, how did I ever not notice it before... when the rpms are almost back to idle speed there is a HUGE vibration/shudder coming from the area of the torque converter. Could this be my issue? My flywheel perhaps? The TQ itself? Wouldn’t be the input shaft, all forward gears are operational, albeit they feel slow to me... sluggish. But when shifted into reverse(which doesn’t work) or neutral and the engine revved momentarily to about 2,000 rpm and let off there is an unmistakable HUGE shudder at about 1,000-1,200 rpms. It’s done that for I don’t know how long but I can remember it for a ways back. What is it? I can’t find anything online to help me diagnose it, is it a symptom of my transmission problems? Somebody here in this forum, please give me the answer that I’ve racked my brain for for over 2 months now. I’ve read and researched and asked question after question and I’m starting to get tired of it all. Help me fix this issue please. I’m begging over here. Lol. I wouldn’t think that the shudder is normal. Help!!!!! Please!!! Lol
 
Known weak spot on those suburbans. Know someone who had one and went through 3 transmissions before giving up. New trans or new ride...
 
Sorry but I respectfully disagree. Tranny isn’t shot just because you lose reverse or just because it’s acting other than how it’s supposed to normally operate. That’s when you start diagnosing the problem and fix what’s wrong instead of just dumping $2500 at the transmission shop like they all want you to believe you have to do. Transmission shops and mechanics are so fast to just up and tell you that you need to R&R every time some little thing goes wrong with the transmission and everybody believes them because they’re the expert right? Well, to some extent that would be correct, they are supposed to be the experts, but why then do they always say rebuild, rebuild, rebuild instead of fix, fix, fix? Money, money, money. And I don’t just mean money in their pockets, I mean it’s meant to supposedly save the customer money in the long run but when you do all of the work yourself it’s going to take an awful lot of parts to get to $2500 and me saying, “dang, should’ve just rebuilt the thing”. Lol. If I can spend $200, $300 or even $500 now rehabbing it and getting it to last another 3 months even then it’s worth it to me. I don’t want to pay anyone half of what I paid for the vehicle in the first place or 1/3 more than what a refurbished one costs to work on my transmission. If anything I’ll remove it myself and take it to them to be rebuilt. So does anyone have an answer or idea about the feeling I’m getting from under the truck? Thanks, hope everyone has a good evening
 
I don’t agree with it being shot. It may be as simple as the O-ring on the reverse servo piston causing a leak past situation which is causing the pressure to be too low to engage reverse. It never made any loud bangs or anything like that, reverse started going soft one day and the next it was completely gone... but... BUT!!!... I thought the exact same thing as you guys do now about 2 weeks ago, after changing my 4wd selector seitch and rehabbing the exterior transmission and Tcase wiring, all of a sudden the transmission has new life in it. I changed the throttle position sensor and cleaned my throttle body and mass air flow sensor today and the sluggishness is gone from the forward gears now too. There’s no more harsh shifts after changing the 4wd selector switch. I think I’m going to pop the pan again over the weekend and have a look at the pan magnet, the reverse servo piston seal and the pressure switch manifold. And change the filter again while I’m in there. I refuse to throw that type of money at it without at least trying to fix it first. And no it didn’t just get a new transmission or a rebuild, this is the same one I thought was dead back in November that now suddenly has life left in it
 
Mr. Burb, a rebuild is a repair. When the scope of removal, disassembly, cleaning, inspecting, reassembling, testing, installing, filling, and operations checking the component is the same whether you change a gear set or a gasket, people tend to overhaul the entire module while it's apart. It's an economics thing.
 
I'm going to assume you have a 4l80e. I don't know much about automatic transmissions but I am in the process of rebuilding my th400 which I think is similar to the 4l80e. You might want to check the reverse band apply servo and pin. You can check that with the pan off. Maybe the pin is to short. Also look up into the hole where the pin goes and make sure it can still push on the reverse band. If the lug is broken off the band then reverse won't apply.
 
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Your first sentence is stating you just returned home from the auto parts store. I'd get rid of that money pit that nickle & dimes you and requires a lot of time spent to keep it on the road.
 
And... it would seem someone in the situation you're currently in with their vehicle has no room to talk about finding the small, single thing causing the problem and fixing it right. Fowvay is right, there is logic behind the usual practice of overhauling the whole unit if the repair is not obvious and easily accomplished with the unit in the vehicle. This rule is as true of automatic transmissions as it is of any large conponent in the car.

The pump is going out in my Turbo 400 - if it sits more than half a day it takes several minutes playing with the shifter just to get the forward gears to engage, and will sometimes go back into neutral at a stop. It drips from the front of the trans. while it's running and leaves a puddle the size of a sheet of paper every time it's shut off for a while. The transmission has to be removed to change the pump. The transmission was not rebuilt recently so all the components have 33 years and 128,000 miles on them. I could pull the thing and replace the pump for
Would you replace spark plugs one by one as individual cylinder misfires show up?
 
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Originally Posted By: skyactiv
Your first sentence is stating you just returned home from the auto parts store. I'd get rid of that money pit that nickle & dimes you and requires a lot of time spent to keep it on the road.


This is good advice. It will definitely "fix" the issue.
 
I have to agree with those who say don't just jump to a rebuilt or new transmission from the shop. I spent about $300, replaced some aging parts and while I was in there I upgraded the transmission in my RAM 1500 to the Heavy Duty Diesel Engine spec, works like a charm. Not every auto trans issue can be fixed by a backyard mechanic with ordinary experience, but you can probably do more than you might think at first.

I'd never done any (auto) transmission work myself before, with good instructions and careful planning it's no big deal. They are complex and daunting at first glance and modern versions have modern improvements but in the end they all work the same, and it's 1950's technology.
 
Sounds like the sunshell gear to me, but I am surprised it works occasionally?
https://www.youtube.com/watch?v=Gg4tLMCk2a8

Mine went out of my 97 Sierra ext cab with a 5.7 at a 144,000 km's. Common problems with these trannies, and as others have said, it's time for a rebuild or a new transmission. I am not sure why anyone would want to continue dealing with these issues month after month?
 
If the FORWARD gears work and only reverse doesn't work... forget the torque convertor, flex plate, or anything except an internal problem. It might be a valve body problem, it might be a servo problem, but its most likely that one of the friction elements unique to reverse has given up (I forget the power flows on a GM Turbo400 or 4L80E, but if it were a Chrysler 46RH it would be the reverse band).
 
Originally Posted By: SilverSnake
Originally Posted By: skyactiv
Your first sentence is stating you just returned home from the auto parts store. I'd get rid of that money pit that nickle & dimes you and requires a lot of time spent to keep it on the road.


This is good advice. It will definitely "fix" the issue.


Sure, a new vehicle would solve the problem, but the OP may be either unable to afford one or unwilling to give up on this one.
As long as the OP is wiling to chase this problem, then why shouldn't he?
joegreen offers some solid hints as to what the OP might look for.
Worst case, the OP removes the tranny and buys a rebuild kit, since he seems willing to delve deeply.
 
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