Transmission shifting rough. Help.

[kinggrimwood]

Take a 1992 SC400 with 200,000 miles. Original tranny fluid.
What can i do to help the rough shifting. I think i read once that if you do a pan drop on transmission oil that is that old, it can destroy the transmission.

Can someone please give me advice on what to do to save this transmission?

 

[Edwin_S]

How about switching the oil? Get some new Toyota "T IV" (not dexron IV) auto oil, and replace the oil. There's about 2 litres of oil that comes out of the pan if you drain it. Fill her up after that, and go drive using all the gears. After that drain the oil again, and refill with the new oil. Repeat this procedure 2 or 3 times, by then you should have renewed most of the oil in the transmission. That should solve a lot of shifting problems. if it doesn't help, the tranny is just worn up.

 

[Toysrme]

Take a 1992 SC400 with 200,000 miles. Original tranny fluid.
What can i do to help the rough shifting. I think i read once that if you do a pan drop on transmission oil that is that old, it can destroy the transmission.

Can someone please give me advice on what to do to save this transmission?

I spent a summer afew years ago working in a transmission shop. This is complete BS, fed by old, stupid mechanics, and transmission shops that would rather rebuild/swap your transmission.

Start by flushing the fluid.
Afterwards, adjust the throttlevalve cable to provide a shift like you want it. The tighter the cable, the earlier, and harder it will shift. The looser, the later it will shift & the longer it takes (clunks into gear b/c of insuffecient fluid pressure running in the valve body).

How about switching the oil? Get some new Toyota "T IV" (not dexron IV) auto oil, and replace the oil. There's about 2 litres of oil that comes out of the pan if you drain it. Fill her up after that, and go drive using all the gears. After that drain the oil again, and refill with the new oil. Repeat this procedure 2 or 3 times, by then you should have renewed most of the oil in the transmission. That should solve a lot of shifting problems. if it doesn't help, the tranny is just worn up.

I think that's a bad idea. TT-IV is NOT a replacement for Dexron specified transmissions. While Toyota is generally behind the curve in lubricants, they are very good at rating lubricants. They specifically state in the TT-IV tech primer that TT-IV should not be used on Dexron transmissions, and original TT-I transmissions. They would stand to make alot of money in dealerships if it was.
Dexron isn't compatible with any TT fluid.
Personally, I believe them.
As a side note, alot of people go with different transmission fluids on other makes to try to improve the shifting qualities, as all ATF's have different friction properties. If you wanna give it a whirl. Whatever floats your boat!
The bst I can tell you, is that if you experiance *any* slipping in the transmission. Park the car, flush the fluid & go again. Driving a slipping trnasmission for just a very few miles will destroy the clutch packs in very short order & leave you with no option than a rebuild/replacement.



















Back to your problem. I strongly suggest going to walmart and buying afew jugs of Super-Tech Dexron III. It's cheap (Around $5 for 4 quats), a basic mobil 1 ATF (So you know it doesn't royally suck), and it's good to flush with because of that.

If you're not comfortable flushing the transmission. Drop the pan & clean everything. Put it back on & refill. Idle the engine & shift into all positions on the gear stick. Drive the car around a few min. Park & shift back into every position.
Stop the engine, let it sit until you're not afraid of burns, drain the pan & refill.


You should do at a bare minimum of 2 pan & refills on that transmission circtuit to statistically change the majority of the fluid. On a personal note, you should do 3 drain & fills. & a great idea for someone that NEVER flushes a transmission is to do a drain & fill with every oil change until you can get around with it.
(Just like adding an auxillary cooler & possibly filter, will solve more than 90% of transmission failures.)

 

[kinggrimwood]

I spent a summer afew years ago working in a transmission shop. This is complete BS, fed by old, stupid mechanics, and transmission shops that would rather rebuild/swap your transmission.

Start by flushing the fluid.
Afterwards, adjust the throttlevalve cable to provide a shift like you want it. The tighter the cable, the earlier, and harder it will shift. The looser, the later it will shift & the longer it takes (clunks into gear b/c of insuffecient fluid pressure running in the valve body).






I think that's a bad idea. TT-IV is NOT a replacement for Dexron specified transmissions. While Toyota is generally behind the curve in lubricants, they are very good at rating lubricants. They specifically state in the TT-IV tech primer that TT-IV should not be used on Dexron transmissions, and original TT-I transmissions. They would stand to make alot of money in dealerships if it was.
Dexron isn't compatible with any TT fluid.
Personally, I believe them.
As a side note, alot of people go with different transmission fluids on other makes to try to improve the shifting qualities, as all ATF's have different friction properties. If you wanna give it a whirl. Whatever floats your boat!
The bst I can tell you, is that if you experiance *any* slipping in the transmission. Park the car, flush the fluid & go again. Driving a slipping trnasmission for just a very few miles will destroy the clutch packs in very short order & leave you with no option than a rebuild/replacement.



















Back to your problem. I strongly suggest going to walmart and buying afew jugs of Super-Tech Dexron III. It's cheap (Around $5 for 4 quats), a basic mobil 1 ATF (So you know it doesn't royally suck), and it's good to flush with because of that.

If you're not comfortable flushing the transmission. Drop the pan & clean everything. Put it back on & refill. Idle the engine & shift into all positions on the gear stick. Drive the car around a few min. Park & shift back into every position.
Stop the engine, let it sit until you're not afraid of burns, drain the pan & refill.


You should do at a bare minimum of 2 pan & refills on that transmission circtuit to statistically change the majority of the fluid. On a personal note, you should do 3 drain & fills. & a great idea for someone that NEVER flushes a transmission is to do a drain & fill with every oil change until you can get around with it.
(Just like adding an auxillary cooler & possibly filter, will solve more than 90% of transmission failures.)

Thanks for lots of information. However I do believe that Toyota Type T IV is the oil required for this transmission behind the v8. You mentioned using Dexron stuff, which according to your service bulletin you posted would be incorrect. The cheapest i can find the Type T IV is $5.00 quart at one of my local toyota stealerships.
Should i pan drop and refill myself, or would it be cost effective to pay my mechanic who said he'd flush and refill with proper fluid for $90? Toyota and Lexus both quoted me $200.

 

[Nick M]

What can happen to an old transmission that has never had the fluid changed, is the friction disk in the clutch packs can get wiped clean. ATF has a lot of friction properties, besides lubricant.

The trans has never had service, it gets flushed and feels great. For a while. And the new fluid can wipe the friction disk clean. This is why places like grease monkey and jiffy lube won't do a high mileage flush. This scenario has played itself out many times. Which is why those peopl in the trans shop mentioned it.

This is complete BS, fed by old, stupid mechanics, and transmission shops that would rather rebuild/swap your transmission.

Moderator or not, I would watch what you say. You have made a false statement and insulted people in the process.

 

[Edwin_S]

The 1UZ gearbox requires "T-II" oil, it is mentioned on the oil drainplug and the dipstick. However, the Toyota T-II transmission fluid is replaced by the T-IV oil, so you should put that in.

Never put a Dexron oil into a toyota gearbox that has the T-II or T-IV marks on it, it will shorten the transmissions life significantly.

 

[trend]

what oil to use

please help what is the correct trans oil our deler uses dexronIII

The 1UZ gearbox requires "T-II" oil, it is mentioned on the oil drainplug and the dipstick. However, the Toyota T-II transmission fluid is replaced by the T-IV oil, so you should put that in.

Never put a Dexron oil into a toyota gearbox that has the T-II or T-IV marks on it, it will shorten the transmissions life significantly.

 

[samsdad]

Valvoline recommend Maxlife

Go here http://www.datateck.com.au/lube/valv_auMS/default.asp and look up your vehicle. Most oil companies have similar online "Books"