I have been having some transmission problems the last couple months.

It will slip going into 2nd and 3rd gear but only under part throttle never under full throttle.

Its not slipping badly the worst it has ever slipped is 1000rpms before it caught itself normal is 500 rpms.

When cold it never slipped until it got warm. Fluid looked good but i was thinking it was maybe bad since the heat issue.

I was plaaning on changing the fluid today until i decided to unplug the drop resistor and drive it around.

The result it shifts very hard which i know is normal but there was no slipping.

So what the hell is wrong with my trans? Something vacumn related?Solenoid?
I'm not familiar with trans parts so any help is appreciated.

I"m planning on going built auto but that will have to wait till winter so i'm just trying to keep mine going till then.

 

so no tranny experts here

 

still loking for input

 

Check the adjustment of your TPS. 1K ohm of resistance when the throttle is closed and 9 k ohms of resistance at WOT. Make sure the sweep is linear and clean.

Do a tranny flush, drop the pan and clean the magnets and make sure the screen is clean as well. If the magnets only have the typical build up of sludge on them, then your tranny is probably just fine. If you find metalic particles on the magnets, then your clutches are probably shot and it's time for a new tranny.

EDIT: Measure the dropping resistor, It should be 11.2 - 12.8 Ohms. If it's resistance is too high it could cause weak shifts.

 

or it could be the solenoid pack in the transmission.....mine did the same thing but with almost 200k on the clock i didnt take a chaance on that part so i bought a used tranny from toms4n.com u can et the solenoid pack from transtarindustries.com i believe it was like 120 bux

 

sounds like a drop resistor failure as mention above. either that or your clutch packs seem to be a little burnt or worn out

 

DR resistance tolerance 11.2-12.8 ohms

 

Thanks Jime, I'll edit my post.

 

i never thought about the dr to be to high so i will check that. I have always heard of it being the other way around causing harsh shifts.

I will also check the tps.

I have the trans pan gasket and bolts so i will do the flush in the next couple days.

hopefully its not major i will update when i find out more info.

 

Is your CEL comes on??, The transmission you have is a RE4FO4A, the Soleniod is known to failed, the EPC (Electronic Pressure Control) Solenoid is the one that raises your pressure according to your throttle opening, if this is bad, you would have max line pressure, which keep the Trans from up-shift,
Not vacumn related. feel free to contact me, I have some Transmission here to look at.

 

No cel.so you would think it's the epc solenoid. Please elaborate on this. I sthere anything i can do to diagnos the problem?

 

If your EPC failed, your CEL would comes on, I do not have my notes at home, I'll dig them up at my shop and get back to you tomorrow,

Mai
**

 

4th gen tps should be closed 0.5 k-ohms and open 4.0 k ohms

mine is at .729 closed and 4.18 fully open.
Its a little off could this cause the slipage

My dr is at 12.2

 

No, the ECU will accomandates the differ if it with in the alowable range.
On TPS I normally measure Voltage, closed at .75v to wide open 5.0v

 

i just measured the wide open/closed throttle switch. There is no continuity at all. there is suppose to be when closed but not when open. I think i'm going to replace the tps. Could this part have any effect on the slippage?

 

Possible, but I'm keep thinking that would set a 0120/0403 TPS circiuit code, just to be sure, check your feed, red wire 5.0v key "ON" engine off, if good, backprobe the WHITE wire (+) and BLACK wire (-) and move the lavel, you should see .75 to 5.0v.
TPS is like a light dimmer, it is a variable resister (potentioneter) that mean it could be a intermitted problem, when you check it, you are looking for a smooth movement in voltage

 

i get 5v from the red wire.

I may be doing the other part wrong but i get 4.3v from the white wire regardless of throttle position.

I think i'm going to get a tps from a junk yard in the morning and see what happens.

 

Fanaticrockford,
You get the TPS????,

Mai
**

 

I went to the yard this morning but couldn't find one. I found a 98 tb with tps but they wanted to much for it. I think they changed the tps late in the 97 year anyway.There is another org member selling one and i'm just waiting on a pic to see if it's the same as mine.