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To use lucus stop slip or to not use


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Hello all,

my main question is whether using lucus stop slip will help my situation or just make it worse. I have an 09 kia spectra ez with 212k miles. This winter ive noticed that the transmission shifts rough when its first driven in the morning. It only does this when i go through the lower to mid gears. Its worse when its colder. I try to let it warm up for a couple of minutes before i drive it when its been sitting overnight. So I was wondering if i added a bottle of lucus stop slip after draining a quart of tranny fluid. Or would it make it worse? I appreciate any advice on this!

This topic was modified 6 days ago by Taylor
3 Answers

Well your weather between a rock and a hard place there those transmissions are kind of weak and generally no additive will help them at all. That stop slip works pretty good on Old American vehicles but they have completely different design internally than your Korean car does. You're really better just letting the car warm up before you drive it hard because if anything a thick oil will make it even worse when it's cold


Hmm ... how are American and Korean automatics different?


Korean conventional automatics often have a built in adaptation program that’s easy to initiate (modern ones are better built excluding some early 10s ones that could unbolt them because Kia didn’t use thread-locker)
An adaptation on a Ford conventional automatic? Well that requires a tool and a special code… basically either a very expensive scan tool or a trip to the dealer…

@dan but that's software. Scotty says "completely different design internally "

Oh. what scotty probably means is that old automatic transmissions had much bigger tolerances and simpler design compared to a modern vehicle? I guess... quite honestly, I am not sure.
all automatics I've seen from the US like the Ford 4F, 5F (I think that one is actually a Jatco), 6F- I might be missing something but they all look almost the same to me, I don't have any info about any of their bigger or older ones as they're inexistent here.
But then still the same basic principles still apply, it's still made up of clutches, brakes, bands, drums, solenoids and planetary redactors...
I mean be it an early 1980s GM Turbo-Hydramatic (the first transverse GM transmission)

Or a 2016 GM Hydra-Matic 9 speed

inside the same principals still apply,

things like design, tolerances, gizmos, and all of those are new, but the rest I don't think has changed much...
(design wise the first ones were odd, using the chain instead of an input shaft and rotating the entire transmission in such an awkward way - I guess it was to take up less space...)


Try a clutch adaptation first.

check if the fluid is getting a bit dirty, it so replace.

additives are for when you have no plans of fixing anything.

(I’m guessing the spectra is just another name for the 2nd generation Kia Forte)

What do you mean by clutch adaptation. I ask because its an automatic transmission and everything i look up on clutch adaptation is for manual transmission.

The fluid is definitely dirty, however I doubt it was ever serviced. The car was given to me about 2 years ago and it had 193k miles on it at that time. I wonder if I should just take Scotty’s advice and just let it warm up before driving it.

you transmission computer automatically adjusts clutch pressure as the transmission ages.

@mmj sometimes in the search of the best shift pattern, it ends up with the completely wrong values - ask Ford Focus owners, some of them end up reset the TCM once a month...
Some cars require you to use a scan tool:

But on some Hyundai-Kia cars you can just go from N to D three times waiting 3 second in each gear (or something like that) and than taking it for a drive, but I'm not sure if that applies to an 09 spectra and I'm unsure on it's specifics
A lot of the time this helps, but it may drive worse and it may never achieve a drivable calibration again... it's a risk, although personally I think it's a small one.