Late shifting after fluid/filter change on 1991 Custom Cruiser

I've got 133,000 miles on my 1991 Custom Cruiser, and to knowledge, the transmission fluid had never been changed.  So, I figured it was time, since they recommend it at 100,000.  The transmission was running fine before the change.

The change was done yesterday (Friday) and when I got it back, it is now late shifting.

It won't get out of first until it hits 20 mph and around 2400 rpm.  Way too late based on my earlier experiences!

Then it needs to get up to 2400 rpm again to get into 3rd.

Overdrive used to kick in around 55, but now it needs to hit 65 and high rpms.

I checked the level, and although it is hard to read since it is new fluid, it does appear to be above the crosshatch lines.

I'm taking it back to the shop (regular shop, not a transmission shop) for them to check Monday.

Would excess fluid do this, or is there something else?

I'm regretting the change!

Many thanks!

I fixed it.

After reviewing some other sites discussing this same issue, I tried this trick.

I put the car in reverse and held the brakes steady until I got up to about 1500 rpm. I did this several times.

Apparently, this creates reverse pressure on a throttle valve component that can unstick it.

It is now shifting properly.

I will have the fluid level checked at the shop Monday just to make sure.

Hope this will help someone in the future.

Going to have to remember that little trick even if it makes no sense to me at all! 

Ditto.

I'm going to try it as soon as I get out of work. My hard/late shifting issues are back again. My OCC only has 99k now!

Please report back and share your experience. I hope it works for you too. 99K on a 92 is fantastic!

If the throttle valve is hanging up, make sure your new fluid isn't picking up grit real fast.  If it is, flush it out again, and then keep and eye on the fluid and keep flushing and driving until the fluid stays clean. Really dirty transmissions can get the fluid saturated with grit after as little as 80 miles, so keep a close eye on it. You don't want that stuff just floating around as it'll gently sand everything down and then you'll have crossleaks everywhere and the trans will be done.

Would any grit be picked up by the new filter that was installed? If the grit was causing the valve to hang, it would appear the "trick" released it and unstuck the valve.

If the garage did the machine fluid exchange, it may have put unusual pressure on the ball valve. If there was some varnish buildup on the passage, it could have caused the valve to stick. Another possibility is that the new fluid made any varnish buildup sticky, and the ball could then get stuck in the goo. The reverse pressure thing is interesting, and I will also put that in my book of tricks, because I have a 92 OCC with just over 100K on the clock.

No.   The filter catches big stuff, not grit.  Long story, but you can go here and read the entirety of why.

PS - there is no varnish inside transmissions. Never ever seen it. Different chemical action going on in there than in the fuel system.

After returning the car for inspection today, we determined that is was overfilled. They drained off some fluid and all is good.

Nobody at the shop knew about the trick, and they didn't seem too intrigued by it either. They are not a transmission shop, so I guess I'm not surprised.

The trick did seem to work for me, no more hard shifting. Still gotta change the fluid again.

The best thing you can do after a fluid change is to install a Magnefine filter. The new fluid is going to loosen up a lot of trash, and the Magnefine is a sub-micron filter that will take out all of that stuff.

It is a documented fact that after a fluid change, material increases in the new fluid. The Magnefine will take all of this out of the fluid. You're good to go after that.

The stock filter will not catch much at all, besides the big stuff.