Transmission cooler.

[technocj]

I would like to install a trans cooler on my 86. Other than trying to determine by feeling the existing trans fluid lines for a temp difference, does anyone know which line to the radiator trans cooler is the inlet? Thanks!!

[timsrv]

I've actually had to determine this before while installing coolers, but don't remember now which one it was. I think it's the bottom one that's the inlet to the radiator cooler, but don't take my word for it. It's easy to verify. Just disconnect one of the lines (wherever the easiest spot is), then start the van for just a second or 2. If you keep you eye on the disconnected hose while it's running the direction of flow will be very obvious :yes:. Tim

[gushaman]

Lol I did that with my 91 f250 diesel to change the fluid out with a bucket.also diesels will run on atf

[Mackd]

Tim, Vanco, Gwen (or anyone else that knows), I need your help. I installed the Griffith Radiator. I got every thing plumbed in just fine. When I started the van I got what looked like chocolate milk shake coming out out of the Radiator. There is no water what so ever in the oil - so I think my HG and block are ok. Is my oil/transmission cooler shot? When I put the van in gear to move it, the Transmission spins, but does not engage, which is why I think this is an issue with the transmission cooler. This is a bit embarrassing so please be gentle :) Thanks for any assistance/guidance you can provide.

[timsrv]

Check the fluid in your transmission. If that also looks like a milkshake, then you'll know where it came from. Other than somebody physically putting fluids in the wrong places, the only way to mix antifreeze and ATF is via a bad transmission cooler (the kind that's built into a radiator). If the Griffin radiator doesn't have a transmission cooler built in, then it had to have happened with your old radiator.

[Mackd]

Interesting response. Unbeknownst to me, I decided to take my OEM Radiator to a local shop to get recored because my van would run a bit warm on hills or when sitting in traffic. The technician informed me that the cooling tank on the transmission side was cracked. The radiator was repaired, but I purchased a Griffith as I saw this as a good opportunity to make the change and have a back up. This explains why my transmission was acting weird prior to the radiator swap. I know this is a silly question, but a wise person once told me "there are no such things as stupid questions, just dump mistakes," so..., Do I just flush the Transmission? Is the transmission ruined in your opinion? Thank you so much for responding!!! Please know that your knowledge and experience is appreciated by the entire TVT community.

[timsrv]

Automatic transmissions are sensitive and anything other than ATF is not good for them. There's too many variables to know if your transmission is shot, but the fact that it does not engage is not good. Still, it would be hard to condemn the transmission without giving it a fair chance, and trying to drive it with antifreeze in there is hardly giving it a fair chance.

As a mechanic I ran into this issue a couple of times. Both times the transmission was still functioning adequately when the bad cooler was discovered (short period of time running with contaminated fluid). Both times I drained and flushed. Draining and flushing is not very easy unless you have expensive flushing equipment (I did not).

The thing with automatic transmissions is when you drain them, you only get less than half of the fluid out........unless you take more extreme measures. This is because fluid gets trapped in the torque converter. In both situations I decided the lesser of two evils was to drill a hole in the torque converter to drain the fluid. I used a 5/16" drill bit and was very careful to limit how far the drill bit penetrated. Next I positioned the torque converter so the hole was at the very bottom and let it drain overnight. The next day I tapped the hole using a 1/8" pipe tap and used some bent Q-tips to drag out any metal shavings. Next I installed a pipe plug with some Teflon tape. I filled the transmission with ATF, drove a couple of miles, then drained and filled again. Both times I removed the pan to get as much out as possible and also replaced the strainer/filter.

The 1st car was a 70's Oldsmobile with a THM-350 and that customer continued driving without issue for many years. The 2nd car was a Camaro with a THM-400 and that one only made it another 10 miles before the transmission started slipping and failed.

If your transmission was exposed to contaminated fluid for very long and if it already had a lot of miles on it, I wouldn't hold out a lot of hope, but you never know. Based on what you said, my guess is your transmission is toast. Tim

PS: Before you drain it, check the level on the dipstick. Based on how full it is, you can guestimate the level of contamination. After you drain, remove the pan and check the magnet and the strainer for particles. If it looks clear, it might be worth trying to flush and save, but if you find a lot of particles, I probably wouldn't waste the time/fluid. Tim

[Mackd]

What about getting this gunk out of my cooling system? What do you recommend? Have the radiator hot soaked? Remove the coolant flush plug from the left side of the engine block flush and drain? Remove the hoses and clean them? I would hate to rebuild the tranny only to have this gunk still in the cooling system. I would greatly appreciate your recommendations/advice. Thanks again for responding.

[timsrv]

Here's a post I made a while back explaining how to flush: https://www.toyotavantech.com/forum/showthread.php?446-Overheating-van-coolant-loss-(a-lot)-water-pump-shot&p=2735#post2735

[Mackd]

I totally forgot about article, thanks for sending.