Towing reduces risk but I don’t think a quart of gear oil will have much effect in 10 or 20 miles of travel. Some of the nonsense transmission additives that I’ve seen looked like gear oil. If were my truck I would take care of it next month.
With your most recent post I think more damage has been done from operating low on fluid than the gear oil could cause. The gear oil is not terminal. It will drive with gear oil, it just doesn’t have the additives for long term service.
So I’m guessing that even after the fluid exchange is done it still won’t function. So I’m trying to steer through this maze and I welcome your opinion.
Is the transmission working now? With the fluid at the normal level?
I haven’t done anything yet. I think it was bone dry when I put the quart of oil in there. Only reverse worked before and now. I haven’t added fluid or anything else. Fortunately there was only the quart bottle of gear oil on hand and that wasn’t full. So exchanging the oil for fluid will only bring me back to square one, which is reverse.
Add enough ATF to bring the level up to normal and check if the transmission works. The gear oil isn’t going to stop the transmission from working but it will have an effect on the long term life of the transmission.
“The back story is that this transmission wouldn’t drive in any of the forword gears, only reverse. And it had no fluid. Through a confluence of circumstances I put the oil in. It’s my problem but not my truck.”
Thanks for the additional information . . . that certainly puts a new perspective on things
By chance, does the truck belong to your significant other . . . ?!
Anyways, do you know how the transmission came to have no fluid?
How many miles are on this truck, by the way?
If the transmission flush does not fix all the transmission’s problems, that is certainly too bad for the owner. But your quart of gear oil was not the reason, and not even a significant factor, in my opinion
I’m thinking a large part of the reason the transmission was not operating at all . . . before the quart of gear oil . . . was the lack of fluid. I’ve seen this a few times. It often happens when somebody was doing repairs and forgets to replenish the fluid(s)
So you think it’s possible that after restoring the fluid to normal levels the forward gears may work?
Very intuitive. But I would still like to solve the problem and get it running. Thank you for absolving me.
“So you think it’s possible that after restoring the fluid to normal levels the forward gears may work?”
Quite possible. I think you have a fair chance of success.
As for absolving you, that’s not really for me to do. The transmission wasn’t working, and had no fluid at all, before you even laid hands on it. Your quart of gear oil was probably just a footnote, in the whole story
Thank you. I don’t know how it lost the fluid and there is close to 200,000 miles on it.
If by some fluke chance the transmission shifts again, it’s not a vehicle that I’d venture far from home with.
An automatic trans with no fluid or very low fluid can be damaged in seconds, much less minutes.
Fill it and pray.
So if it’s damaged as a result of no fluid, do I have it repaired or replaced?
It’s at the mileage where a rebuild may be looming, in my opinion
Low fluid or no, it might have been due soon, regardless
You’re not paying for the possible transmission overhaul/replacement, are you?
Anyways, if an overhaul/replacement is necessary, I suggest either getting the existing transmission overhauled at an independent transmission shop, or having a jasper transmission . . . for example . . . installed by a reputable shop
If an overhaul is in your future, it might be worthwhile to consider also having the torque converter overhauled at the same time. and have the cooler and lines flushed, at the same time, to make sure any possible debris is flushed out of the system
Just out of curiosity, what engine is in this truck?
Do you know if it is has the 4l60E or the 4L80E transmission?
One more thing . . . is the truck in good condition overall? Not rusted? Fairly well maintained?
What I’m getting at is this . . . is the truck worth an overhauled transmission?
My thinking exactly. This truck was never maintained. The oil has not been changed in years. All the indicator lights are on, engine and a few others. I don’t have the answer as to the transmission at the moment but will tomorrow.
And yes, If anyone pays for repairs it will be me.
Wow, so you’re dealing with a truck that’s led a hard life, and not been taken care of properly
Is the motor at least in decent shape?
A transmission overhaul is cheaper than a new vehicle, but I don’t know if it makes financial sense
What is the truck being used for?
“indicator lights” . . . so the check engine light is on, possibly along with other warning lights?
Do you know what fault codes you have?
If so, I could give you some pointers, because we have tons of GM trucks in our fleet
If you get that transmission going tomorrow, you should plan on an immediate oil and filter change, and a tune-up for the engine.
The truck is used a couple of times a week. It is actually needed but the owner has little cash to maintain it. Most of the week it just sits. And I know little about it right now. I will try to get all that information tomorrow. You’re right, I need to give it a complete evaluation before I put money in. I don’t know how to get the fault codes on that truck.
As for retrieving fault codes, there are a few possibilities
Go to autozone, for example, with the truck, and ask them to retrieve the fault codes for free. Many parts stores apparently will do this, because they hope you will buy the needed part(s) from them.
If you do this, have them print out or write down the fault codes, not their interpretation. For example, if the code is P0301 misfire #1 cylinder, have them write down that, not their idea of what you need to buy
The other possibility is to buy your own cheap code reader or scanner. The super cheap ones will just read out P0301, but not tell you that it means misfire #1 cylinder. The slightly more expensive ones will read out the code, tell you what it means, display live data and show if the readiness monitors are complete
If this is a one-time thing, then perhaps you want autozone to retrieve the fault codes for you. However, bear in mind that you’ll need to go back there to clear the codes afterwards. And you won’t be able to look at any live data while you’re working on the truck
If you decide to buy a tool, consider how often you’ll be using it.
In any case, there are plenty of websites that will give you helpful advice about what you should consider doing to resolve a particular fault code. Our website is a good example, and you can interact with us. There are also websites that are non-interactive, but list out some common possibilities, such as engine-codes.com
If this truck is used for work, meaning if it is used in the performance of someone’s job, I would seriously consider repairing/overhauling the transmission, as needed. To clarify, if it’s used at a jobsite, or used to deliver/haul stuff, it could be worth repairing, if rust has not structurally compromised the truck
If it’s just used to get the owner to work 3 times a week, and the job is only 5-10 miles away, it might be a different story, depending on the condition of the truck
Good luck . . . !
OP …when the fluid is drained by dropping the pan, not all the fluid comes out. There’s fluid stored in the valve body and even more in the torque converter. So you need to get all the old fluid out, somehow or another. One way to do that is by repeating the “drop the pan, replace the filter” several times, driving a bit in between. On some vehicles it is possible to drain the torque converter separately, but this is not as common as it used to be. If you do that enough times, almost all of the old fluid, including the gear oil, will be extracted from the system. Plus you’ll have a new filter installed.
The fluid flush technique will probably do the job too if it is done correctly, but you may end up with a clogged filter that will need replacement. When you do either of these, make sure to ask the shop to inspect the bottom of the pan for unexplained metal debris, and clean the pan of all the accumulated gunk.
With this being a beater of questionable maintenance and reliability of the entire drive train it might be worthwhile to crank it up, top off the transmission and attempt to drive it around the block if that can be done safely considering the possibility of it going belly up at any moment. And it it drives OK then drop the pan and refill with ATF and use the truck normally for a week or two and if there are no problems drop the pan again and refill again. The gear oil won’t likely cause a sudden failure of the transmission but it will probably affect the clutches by causing them to drag and wear. But Lucas sells an ATF additive that is significantly thicker than 90 weight gear oil that apparently doesn’t cause immedtiate problems.