dsls400

Hey all,
1994 ls transmission has been shifting weird. To start. last week it was shifting great accelerating, but would struggle downshifting on its own(like slowing down a standard transmission without pushing clutch in) Now, it is having that issue, as well as shifting from first to 3rd like instantly then also od quickly after that. Now, I have been fooling around with the shifter and if I shift it manually it shifts smooth accelerating and decelerating. Also, if I let it shift automatically from the 2nd gear location it will shift correctly from first to second, then I will have to shift to D for it to continue as would be expected. The filter and fluid were changed 2 months ago as routine maintenance, I used the recommended fluid for that, as well

The car has nearly 240k on it. and has been flawless

I did some research about this issue and cannot really find exactly what I'm experiencing .Most posts about this lean towards #2 solenoid. I did the engine/transmission diagnostic as instructed here on the forum. There are no codes. Also, the fluid levels are where they should be and a nice pink color.

I'm guessing the problem is the solenoid, but not the electrical part of it that would throw a code? I think it must be sticking, as none of these symptoms happen all the time downshifting or accelerating. Does this sound right?

Thanks for your input
Skip

LScowboyLS

by far the most common cause of shifting issues on a '94 with no codes is failing ECU capacitors

this makes perfect logical sense if you think about it, for three reasons:

● the LS400 does not have a seperate computer to control shifting, all shift decisions are made by the ECU
● the 94 LS400 (and several other years) have a known factory defect in the ECU capacitors
● Florida is by far the most common state for this issue to show up in, must be exacerbated by heat/humidity combination it seems

PureDrifter

iTrader: (10)

Actually the single most common issue for shifting issue on the LS is simply old/incorrect fluid type. Hundreds of threads throughout the forum (SC, GS, LS, and IS subforums) support this.

The Aisin transmissions in our cars reqire reasonably clean Toyota T-IV fluid. Swap all the fluid out (fluid exchange, not power-flush) for fresh fluid and then see if you still have an issue, usually that resolves most minor issues.

LScowboyLS

actually, from a historical perspective, that is correct, this epidemic of ECU caps failures is a fairly recent phenomenon, I think that is why it is so difficult for some of the "old school" to accept, but as these cars continue to age, what fails the most often is a changing dynamic.

as with any transmission issue on any car though, the first step is always fluid and filter change with the correct manufacturer specified fluid. - if the car has gone an excessive number of years or miles (like greater than 7-8 years or more than 100K since a fluid change), then the new fluid should be introduced a quart at a time, over the course of a year, so as not to "shock" the transmission into a premature failure. - this is why it is all to common to hear of someone who had the fluid completely changed and then a transmission failure happens soon afterwards!

nostalgi

How do you do that in practice?

LScowboyLS

crack the drain plug, catch a quart, tighten her up good, add a quart of fresh T-IV

repeat this in a couple months

double check that you do not leave a leak at the drain plug, keep checking fluid level with car in Park, transmission hot, on a very level surface, I would check it daily.

python

iTrader: (4)

http://www.ebay.com/itm/like/390574181548?lpid=82

PureDrifter

iTrader: (10)

www.lexls.com/tutorials has a fluid exchange tutorial you can do with relative ease at home.

LScowboyLS

I have never had luck with that type on the LS400, however there is are nicer ones of these in the $60 and up range that work well, here are two that do work well on LS400

this one from Mityvac

and this style