ChrisSC300

After driving to and from tampa twice this week my transmission started to slip in 4th gear (my car is an auto). It only did it a few times, it would be if 4th then drop to 3rd, and after a second would go back into 4th. It only did it like 3 times. I drove 4 hours from tampa to jacksonville, and it didnt do it once. Its obvioulsy slipping, but what can i do about it? could it just be the clutch?
Or would i have to replace the enire tranny. If i had to replace the entire transmission, would it be possible to stick in a 5spd? I plan on swapping in a 2jz-gte by the summer time. I hear the 5spd can hold up as long as you dont do 5k chutch drops, but what about the auto? Thanks for the help everyone.

pcmw

ChrisSC300,

If you plan on doing a swap in the summer, then drive the tranny and you should make it fine another 8k miles. Just be gentle on it.

However, if you are not comfortable with a $10k+ project and a month without your car, then you better think about getting the tranny repaired before you fry the whole thing.

In the end, I wouldn't suggest switching from a auto to 5sp to GTE. That would be a waste of cash.

MW

ChrisSC300

Yeah, was thinking the same thing. As soon as i get a new job, i might take a loan out and bump up my project a few months. I have around 215k on the motor as of right now, and its about time for the tranny to go. I dont know about the 6spd into an auto though...not many people will do it. I will have it checked out next week when i go in for an oil change. I do alot of driving though, lots of long trips. I dont know how long it will last.

But could it just be the clutch or something? or is it pretty much a gurantee that i will have to replace the transmission.

pcmw

Auto tranny is a bit more complex than "could it just be the clutch or something" You have several parts that need to be worked on when you drop the tranny down. If it is slipping, you may have some debris floating around. Most shops charge over $700 to just remove and reinstall the tranny. So I would think you are looking at $2,500 for pulling the tranny, a full rebuild kit, and reinstall.

MW

aliga

iTrader: (147)

You may be better off (in terms of cost) buying a tranny from a low mileage sc in a salvage yard, and getting that installed over a rebuild.

Miles B

Checked your fluid level?

stock300

You may want to check out the throttle position sensor just in case it isn't slipping. Slipping to me means that when I accelerate, my RPM's increase but my speed doesn't. The TPS on my Supra was gummed up and this messed up my shift points. It's easy enough to take apart and clean it up. You'll also need an ohm meter to reposition the TPS. Just a thought.

Anthracite SC

I have some slippage downshifting from 3rd to 2nd...
got 150K.

U?

Qmanlexus

Qmanlexus

Hey guy I am having a simular problem with shift points. I have dropped the tranny fluid and replaced with about 3 quarts. No change. But the question I also had was about Stock SC300 TPS? How do you clean it with out damaging it and how to adjust?

ChrisSC300

Yeah, its not slipping into neutral, its just dropping into 3rd for no reason then going back up to 4th. I will look at the fluid levels and try to find out where the TPS is. I will just take it easy with the car untill i figure out what to do.

Anthracite SC

What tranny fluid are you guys using? Redline?

Qmanlexus

Dextron 3 Mercon in the SC300 Only. Chris the TPS should be on the troutlle Body Assy. I not sure about using Red Line. I tried there Fuel Injector & Valve cleaner On my Mazda MX-6 and I just made my car run rumn like s--- for a long time until the Computer finally adjusted it self back to normal. I hear that Lucas makes a good Tranny conditioner But I have never used It.

stock300

The TPS is on the throttle body on top of the engine. It's a small, about 1.5 in. dia., black plastic housing that connects to the throttle plate. It basically provides a resistance depending on the position of the throttle and this is fed to the computer to help establish which gear the transmission should be in. When the one on my Supra started acting up at about 125K miles, I would let up on the gas but the TPS would stick and the wrong resistance was generated for that speed. So when I started to accelerate, it wouldn't always downshift. There are only 2 phillip screws to remove the cap from the TPS and a wiring harness. I cleaned it up with WD40 which worked for a while but eventually ended up replacing it (about $75). The adjustment on installation involves a feeler gauge placed at the throttle stop and an ohm meter hooked up to 2 of the 4 points on the connector. You rotate the cover until the resistance changes and then lock it in place. If your interested, I'll be glad to dig out my service manual (93SC300) after I get home tonight and send out a more specific procedure.

Qmanlexus

Stock SC300 If you can dig that proceedure up on the TPS that would be great. Thanks in Advance