OH! guys who have experience, can you please compare the volume of the oil coming out of the tranny? The car was at idle the whole time, but that doesn't seem like very much flow. I wonder if that is a cause of the hot tranny issues?

 

This is a clue that your build may not be worth much. It could very well be fine and last forever, but you will not know.

There is nothing wrong with conventional transmission fluid. I have used it forever, except on one truck where it was mfr required. Worst case you change it every 10k miles and you are pretty well protected. Best you can do is change 50% of the fluid at every change, so the new fluid will be diluted by at least that much at every change. I worked in a transmission shop and there were an incredible number of non-synthetic fluid transmissions lasting well over 100k with no fluid changes at all (and ultimately why they failed).

I would drive it like you stole it, and enjoy it. When it breaks you deal with it then.

 

Good job! Yes, the flow to/from trans cooler isn't that much, I think it's around 30psi max on most cars. The additional trans cooler is better than the stock in-radiator type, you can have one or the other, or even both but that might cause too much restriction for flow. Your old trans fluid looks pretty good, but synthetic is much better. I don't use anything but Redline synthetic for gear or ATF fluids now, good stuff. I've seen conventional ATF get so hot it boils over and pukes on the ground, ask anyone who has power braked their tranny too long to load up a turbo. When I was doing Ford automatics long ago, I told them to use Dexron, not type F. It's was OK to do this after a rebuild but not before.

 

Went for a test drive, it;s still lagging about a mile or so before it shifts into overdrive. Oh well.

thanks bswarm for the info.

Next test will be the thermal behavior. The whole point was an attempt to get more stable behavior.

 

Cool! Thanks for posting your procedure.

 

I've only rebuilt American RWD & 4WD automatics and a few Toyoglides, so I don't know if they're available for yours...
There are shift improver kits that get installed in the valve body, different stages depending on what you want it to do. The basic ones reduce the slip between gears, resulting in crisp shifts and prolonged life of the trans. You would have to find someone that still does those and let him know what you have, what it does, and what you want it to do. They weren't that expensive, $90 for the kit and a couple hours labor, but that was 30 years ago. I switched shops and the new place didn't want to do them.

 

I have a transmission related guestion. Bought a 94 truck 4x4 auto, a month ago. It was shifting hard when cold. Last week, took it to a transmission shop to have serviced. When we got it back it was still shifting hard. Today i was driving and it got to where you would be doing 35 in od at 5000 rpm. Slowly drove it home. On the way home I checked the fluid and it wasn't even on the stick. Put a can of trans tune in it and it barely reached the stick. Started slowly putting lucas transmission slip stop in it, it still slipped bad. Tonight I warmed the transmission up by driving it slowly up and down the road for 20 minutes. Topped of transmission with the lucas, read full. Took it for a drive and its shifting smoother rhen it ever has. We have snow everywhere so no signs of leaks on ground. Would the shop really leave it low or is there an air pocket that could have caused them this trouble? Really don't think this has permintly solved any problems. Think tranny is gone. Just seems ood. When we left trans shop, they said see you in a week or two. Will drive tomorrow to see if it continues shifting well, just seems quirky. Thanks for any input.

 

Yes, the shop would leave it that low! I dont trust any mechanic, especially if it was a chain store type shop. If its working well now then dont worry.

 

Bad news update.

SO, yesterday as I was driving to work I noticed some improved qualities of the transmission operation. I thought, wow, excellent, I didn't even think there was room for improvement here. This was mainly related to the torque converter unlocking and/or the transmission shifting soon on the throttle position range. Before I would have to go further on the throttle before the torque converter unlocked or a shift to 3rd. Although, admittedly this was a very slight change, regardless I was happy to see it.

THen, on the way home..... As I exited the fwy and came to a stop I noticed the car wasn't moving off the line as it should... soon noticed it was not shifting down to 1st. I tried manually shifting it to first, no go. I was pretty annoyed at this point. Once I got home, I let the tranny cool from 200 to about 150, and started her up and drove her around a couple of miles and the tranny was acting normal again. I thought i'd check the fluid, and I was shocked to find that there is too much fluid in there now. Some funcky stuff is going on in this transmission. During the re-filling I could have sworn I put in 12 qts, but when I checked it was very low. (yes I checked in correct conditions) SO I had to add about 1.5-2 qts before it was at the proper level... and now it's way high???

ALthough i'm pretty sure the fluid level doesn't have much to do with the 1st gear issue, I am going to drain a couple of qts out today and see what happens.

I'm one weekend away from putting in my spare tranny, and taking this one apart for fun to see if I can possible find a 'problem' in this one that is causing this heat issue.

So, to all of those who told me not to touch the tranny.. SHUSH

 

UPDATE:

Today I re-flushed the system ( I am now a freeking pro at this!) and pur in conventional DexronII compatible ATF... THen I put it through it's paces forcing the tranny to heat up as far as I can get it. I tried everything to re-create the issue I mentioned in my last post about the tranny not going into 1st gear, well I couldn't recreate the problem with the conventional oil.

Lesson learned, these transmissions (or atleast specifically one with 229k miles and rebuilt) do NOT like synthetic oil!

I was relieved, and now I have $160 of mobile 1 synthetic atf sitting in my garage that I don't have a use for. lol.

all is well that ends well... that should be more like 'all is well and expensive even when it ends well'

 

What conventional fluid did you use? I have been using Castrol Dex/Merc in my old transmissions with good results.

 

Mobil 1 synthetic only meets Dexron specs. In fact, I looked up the spec's of Mobil and Redline and compared the two. Mobils ATF has a really bad problem with viscosity at very cold temperatures (-40º C =10,040) where Redline stays close to specs (-40º C =52) Redline also exceeded all other specs compared to Mobil. It's very possible your trans has issues with overheating the fluid, which would explain why the level was overfull when hot. I've seen trans get so hot the fluid boils out onto the ground. If I were you, I'd install a good external trans cooler in front of the radiator, and ditch the one built into the radiator.
Do you have oversize tires with stock gears? That would easily overheat the trans.

 

I used the oreilly's brand. It didnt matter to me anymore. Lol. Before this fiasco I had the castrol in there.

 

That Mobil 1 ATF will make dandy bar and chain lube for your chainsaw.

 

Mobile 1 synthetic atf meets the dex II spec and far exceeds it. What it comes down to i believe is that a tranny with so many miles, even when rebuilt recently, needs thicker fluid. (By thicker we understand that i am referring to the friction specs rather than weight).. Regrdless, Im pretty sure synthetic is the problem here not not the brand.
No, i have proper tire size for mh gearing

My friend said he can use thr syntheti. Stuff in his jeeps t case. Im sure ill finf some use for the oil

 

Did you replace your torque converter when you rebuilt the trans? That's where most of the heat is generated, and that's the symptom of a torque converter going bad, overheating fluid. If you replaced it with a performance torque converter, the instructions should have said you need to install a good external trans cooler in front of the radiator. No fluid is going to fix it, the problem will return. Synthetic is better than conventional in handling heat, but when I saw what mobile 1 ATF does at low temps, I wouldn't have used it.

 

Oh, I forgot to mention. Yes, I do have aftermarket oil coolers, plural, two of them! The torque converter, according to the guy who rebuilt it, is brand new OEM. He said it's best to get one by Toyota and I agreed. I guess it is a possibility that the torque converter is bad, or the guy screwed me over and put the old one back in...

 

Well, interesting update. My transmission is shifting through all gears as it should now. So it is properly ahifting out of 3rd i to 4th. Most likely a fluke. We will see. I have not changed anything else.