Experiences w/ Slipping Auto Transmission, Lucas Trans Fix, & Upkeep

Wanting to hear other folks thoughts on dealing with a slipping transmission, if you've tried lucas Transmission fix (or any other product), and how their trucks held up over the years using/dealing with the trans issue long-term/short-term.



For me my 2.4 taco transmission been slipping every once in a while, but since this winter its been more apparent and regular. The tranny has a clean record in terms of upkeep with clean fluid from the prior 1st owner. I've kept up the trend changing it as scheduled. I'm assuming its wear over time, and isn't heavy damage (no notable metal shards in the pan/filter).

Ended up saying the heck with it and tossed a half bottle of the 32oz lucas trans fix in (along with a clean atf change), and lo and behold its driving better than ever with no slippage on a hot or cold day (cold start or driven hot). No gear searching at idle. No more clanking upon accelerating from a stop. Feels more powerful/responsive, and quieter (like it should sound, before the bay sounded louder than it should have for what it was giving out rpm/power wise). Honestly the truck drives perfectly now. Still need to do more heavy testing though to be sure.

Have two 3.4 4runners and sad to say its finally on its last leg, the transmission being one of big issues. The thing was mistakenly driven with low to no atf due to a leak over a long time so some major damage done in there (Person driving it primarily noticed it acting odd, but never bothered to have it checked out before it was to late). But, if we do get it road worthy again may give it a shot anyways with the additive stuff for the heck of it. Not expecting miracles though.



Anyways with you guys that's dealt with slipping/damaged transmissions, how has your trucks held up, and maybe have tips on keeping things going smoothly. Thoughts on additives also? Ended up needing another transmission? Imagine changing the tranny one day myself, but I'll coast as long as I can haha.

 

I actually had this problem on my Tahoe, I put in 32 ozs of the same Lucas auto transmission fix.

That was probably 100,000 miles ago. It slightly slips every once and a while, time for a fluid change dropping the filter only and no flush,
My tacoma is a 5 speed with no issues

 

Much appreciated for the reply, bud! I'm actually feeling pretty chipper as I was expecting maybe 2-3 horror stories replies, but yours was the only one and not only that the vehicle in question wasn't even a Taco, haha.

I'll take that as a good sign that our trucks transmissions are decently solid (given they aren't damaged by user error), since there's so few people to even respond lol.

I'll just keep putting in some additives during each atf change, and see how long it'll go like that. Hopefully the slip doesn't show up cross the hill.

 

I am of the opinion that any sort of fluid or oil you have to add to a malfunctioning transmission isn't actually fixing anything. At best, you're just masking the problem. Like that "stop leak" stuff. You aren't actually fixing the leak...

So, the longer you drive like this, the more likely you'll end up with non-repairable damage later on.

 

have read that some do prolong the repair a bit but as jbrandt stated you're slipping on heavy mud.

 

Hm, isn't that alright to do so and kind of the point? Sure its masking the problem, and certainly not making it better, but as long as the issues aren't showing up then what more could you ask for.

Its not like there's any other way to fix the tranny besides replacing it all together, or doing a almost as expensive rebuild (given its a good shop).

The transmission is shot as it is, and its not like driving with or without the additive will make it not get worse overtime. At least with the additive I can safely drive without the dangers of the issue arising for the foreseeable future.

This thread in itself is about asking how long others that have used additives or dealt with trans issues over the long/short term to figure out just how long you can prolong inevitable dread of replacing the tranny.

 

If I had to guess the oil additive has additional friction material in it to give it more life

 

The Lucas additive actually thickens the transmission fluid and I believe this is what helps the transmission from not slipping or not as much. I probably would not believe this would have worked
if I hadn’t tried it. The transmission otherwise has always had regular oil changes at 75,000 miles.

 

As long as you are operating under the assumption that the trany is likely fubar'd and you're just limping it along until you actually need to replace it, who cares. Drive it until it explodes, then wrap some duct tape on it and drive it another 10k miles.

That said, driving with the additives can most certainly make it worse over time since you aren't actually fixing the problem. The problem could be something that's relatively cheap and easy to fix, like a plugged filter or or a sticky valve or something.

I'm no tranny expert, but if there is the possibility of fixing a minor issue before it becomes a major one, I'd rather go that route rather than masking it and waiting until it gets bad. It's possible that all you'd need (if the problem is solved early enough) is a minor fix involving just dropping the pan, rather than a whole new tranny.

 

Indeed haha it definitely some thick stuff. Was surprised how dense the liquid was, so I decided to use only half the bottle instead of the whole thing just in case. I'm glad your vehicles are still rocking, and thanks for the extra info.

I guess I didn't make it clear enough in my first post, but I already changed the atf, filter, and any grime in the pan already. Hm, I tried looking for other things that could cause the issue as well, but only thing I could find that could be the issue would be within the tranny itself (which is outside my ability to wrench at).

That said a half bottle of $9 lucas seems like a simple way to go to me haha. Vehicle was slipping, clanging out of a stop, and searching gears at idle before, and now every single issue is put at bay with the same brand atf +additive. (the atf in there was also just 2-3 months old, and again I only put in half the bottle which is only 16oz - probably closer to 13-14oz)

To be frank I have a hard time even finding anecdotes or statistics of additives like lucas actually increasing issues. Though I'm not infallible, and honestly kind of on the hick side, so if you do have any sources I'd actually be really interested in seeing them (haha reason why I made the thread).

With that all said though I really appreciate your replies. If nothing else it gives me more caution to figure out what else it could be or alternative solutions. Always more ways to skin a cat as they say.

Things I've done that could be related:
Changed all balljoints upper and lower, rest of suspension from tie rods, struts, and leafs seem fine,
ATF change, Trans filter change, New diff fluid, New Egr +solenoid, cleaned throttlebody/intake mani, new tires, oil/filter, brake/powersteering fluid are fine, no play in tires, new pads/rotors, probably could use new alt/pump/fan belts though

Edit: also changed fuel filter and pump

 

If I remember correctly the transmission HAS to be warmed up before you add the lucas or it will not work correctly, mix correctly

 

Haha yea I'm actually glad I read the instructions for once (before I was about to dump it right in, but then paused and read the bottle). I did it on a running engine with some atf already in then went back and forth with additive then atf repeating till half the lucas was gone. Then I just filled it up the rest of the way with atf.

Next time though I think i'll just mix the two together in a empty can, and fill it that way. Trying to check the dip stick with how thick lucas is is a major hassle. Actually mixing the two I imagine will make it far easier to check accurately. Then again I could just dump the lucas first then atf. Was just to worried the thickness of the lucas would be to much all in one go for my first go at using it.

 

I never meant to say that additives increase issues, only that they don't really solve them, which means they can get worse without you really noticing until maybe it's too late - like leaving a band-aid on for too long, lol.

Transmissions are definitely out of my wheelhouse too, and I think I'd take it to a shop and get their opinion, or at least as you did, try to find other fixes first. Even if you spend a hundred or so on a diagnostic fee, that could be worth it in the long run if it means you don't have to buy a new trans. Sure, the bottle only cost $9, but you're essentially guaranteeing a new transmission (eventually). If it's fubar, an additive literally can't make it any worse, so why not try it...

But if they determine it can be rebuilt, 1) that's very likely going to be less than a whole tranny, and 2) if you catch it early you may not need as many parts for the rebuild, rather than driving it into the ground.

 

Darnit you know what that's good advice haha. I'll go ahead and just have a tech just give it a looker at least. Already got a bad pickle due to our 4runner not getting checked up on, may have very well duped the same mistake if I ended up doing the same with the taco. Much appreciate - saved me from at least not being a flaming hypocrite haha!

Will say if they do end up hitting me with a bill for a rebuild or new trans I doubt I'd ever pay for it. Love the truck, but not that much lol. If worse comes to worse and the tranny is on the last leg I'll probably git good mode and give it my best go at installing a new/used tranny myself. If I fail, welp, at least it'll know I loved it enough to try haha.

 

I originally went that route and the transmission repair shop said I needed a new transmission and that was around 100,000 miles ago. Taho now has 375,000 miles.
They will try and sell you their services.

Because the Tahoe transmission was always taken care of with oil changes and never abused I think I got luck with the additive.

 

Goodness thats pretty astounding. A lot more miles then I was thinking. Shoot if it lasting that long, and still keep kicking on the stuff then I may just have a coke and mix it with pepsi!

So far I've probably only driven on the stuff for two tanks (less than 400miles), and all seems good. Real test will be when ice hits on a tank of winter gas, since I always end up finding more issues in general around that time.

Will be expecting the worse from the tech who looks at the truck, since honestly every mechanic I've met around my town have been more slimy then my slipping tranny (or are just to young/ not experienced enough). Used to regularly go to a solid Hispanic tech I grew to like, but he got sent to another city.

 

replacing a tranny isn't that hard. My brother and I did it back in the day. I was around 15 or 16. We swapped the auto out of his 86 turbo 4Runner for a 5 speed (I ended up buying it off him later). It took us kids the better part of the weekend to do it including messing with the shifters, new pedals, etc... and this was before we had the internet and youtube to look at. Turns out the trany he got was rebuilt wrong so we ended up having to swap another trany in. That time it took like half a day (didn't have to fuss with the pedals or anything that time either).

If I had to do a swap today, I might consider doing a modern motor/trans swap. I'd love to have the motor/trans from my '17 4Runner in my Taco. That'd be sweet.

 

Sorry for the late reply, was hoping to get more definitive diagnosis on the truck.

Ended up going to two different mechanics, and both said the truck is fine and nothing wrong with it. Though I would suspect they didn't do anything other than drive it around a little and stare at the bay haha (probably similar to a basic inspection). Doubt they did any kind pressure testing or data analysis though I'm not sure what tests there are to check the transmission internals.

I'll just keep coasting, and hopefully things run smoothly for the foreseeable future. With youtube and here I think I feel okay doing my own trans replacement given I buy a few more tools to handle it all, but I think for now I'll be good for a while. Certainly reassuring knowing others accomplished the deed smoothly.