Shifts weird when hot.

[nirto71455]

HI Guys,

I just got a 86 GN. It has a TCI 200r4 in it with about 4k. The trans is about 2 years old so it's done alot of sitting. Once you have got it good an warm..........20 miles or so, it starts shifting really spungy and speraticly (shifts to soon). The fluid is very clean and is full right to the line. Do any of you know what might cause this?

Thanks,
Rich

 

[turboost]

Do you have a higher stall converter?

 

[nirto71455]

Naw........ It's just the stock converter.

Rich

 

[MeanBuicks]

That's a good candidate for a pressure test.

The pressures cold vs. warm may tell us something. The fact that the shifts soften up and get earlier tells me that the TV circuit may be quirky.

Do you know how warm the transmission is getting? Is the lock-up working?

 

[nirto71455]

First off, thanks for the replys guys!!!!

I'm not sure how hot the trans is getting. I don't think it's getting overyly hot. I have a huge extural cooler in front of the radiator. It's also about 30 to 45 degrees out right now. I don't have a trans temp guage to let me know the exact tempeture though.

From what I can tell, the converter lockup isn't working. This trans will not shift into OD until your at 65mph. It kind of anoying but I'm told that's how TCI sets them up. The three times I was on the freeway, I couldn't tell if it was locking up. I tried tapping the breaks but it didn't seem like it did anything.

Thanks again for helping!!!!

Rich

 

[MeanBuicks]

I still recommend a pressure check on that transmission. You should also run an electrical check on the TCC system; ie. power, ground, sol. resistance. There are many threads in the archives concerning TCC diagnostics.

Have you had the pan off yet to see if there is anything out of the ordinary lurking in there? The TV valve may be getting sticky and may get worse as the unit warms up.

The 65 mph 3-4 shift is not an intentional modification, but could be due to the 3-4 throttle valve assy. that's in that particular valve body. Let's save that problem for last though.

Also, do you know if a fresh converter was installed along with this transmission or is that the original, stock converter?

 

[nirto71455]

Thanks again...... I'll look into everything you mentioned. The converter is the original stock. It's got 84k on it.

Rich

 

[MeanBuicks]

That's kinda strange.

Wonder why the original transmission was replaced, rather than rebuilt, and why the original converter was put in the new one?

That's one way to potentially cross-contaminate components.

 

[nirto71455]

I was told that the pump started leaking on the orignal trans and thats why it was replaced. I have the trans "BRF" that came out of the car. I don't think he would have put the sock converter back in if the trans was circlating crap through it........ but who knows.

Rich