perZ

Hi!


Sorry if asking a dumb question. I've been reading through several posts without being able to tell wether all 700 auto transmissions should have a stock cooler? (all talk is about extra/aftermarket coolers) If so, is it part of the engine radiator or a separate one?


My car is a 350 TPI '89 and I don't think I can find any cooler... problem?


//Per

no new tires

The stock cooler is in the rad. You should -add- this http://www.summitracing.com/parts/bmm-70264

OrangeBird

iTrader: (1)

Hi Per ,

Yes , all automatic equipped cars come with a transmission fluid cooler . On our cars , it's built into the radiator and is evidenced by two metal pipes (metal tubing) plumbed into the radiator usually on the car's right hand side . these pipes are much , very much smaller in diameter that the coolant hoses are , and as such a quick look at your radiator will tell whether they are still properly in place on your car . They should be . There is no good reason to remove them , but sometimes hack repairers will "loop out" the lines if they're leaking rather than doing the job right and fixing them proper .

Bottom line is , if you have two metal pipes running from the right side of your radiator to the right side of your transmission , you fine . Also , No new tire's aftermarket one is a good idea if your regularly flooring it , to get rid of the excess heat

perZ

Alright Thanks to both of you! Tonight when I go to the garage, I'll have a good look for the transmission cooling pipes on the radiator. I think that the radiator might have been replaced with an aftermarket one, let's hope the pipes are still there.


//Per

AlkyIROC

All factory cars with an automatic transmission have coolers and the majority of the time, they're built into the rad. These work just fine in a stock application. Even the smallest cars with automatic transmission will have a cooler. My race car uses a rad from a Pontiac Firefly and it has a cooler built into it but I don't need to use it.

As soon has you swap the converter to a higher stall, you no longer have a stock application. An external cooler installed by itself or inline with the factory cooler is required. Inline is recommended for street use.

Heat is the number one cause of transmission failures. Transmission oil should be at or a little above the temperature of the engine. Oil that's too cold is almost as bad as too hot.

There are different way to install an aftermarket cooler but to me this is the best way to do it.

Hot oil...
Oil coming out of the transmission is fed through the external cooler to remove as much excess heat as possible. It is then directed through the OEM cooler. If the external cooler was too efficient, the OEM cooler will bring the temperature back up to an operating range depending on the coolant temperature. Running the hot oil through the external cooler first doesn't for the engine coolant to try to remove engine heat and excess trans oil heat.

Cold oil...
If the oil coming out of the trans is below operating temperature, the external cooler should do very little but the OEM cooler will then bring the oil temperature up to help warm up the oil faster.

If the oil goes through the OEM cooler first, the rad will increase or decrease the temperature depending on the coolant temp. If the external cooler is second then hot oil will be brought down to a lower temperature which can be lower than the recommended operating temperature.

So if you install a higher stall converter, get an external cooler. Stack plate design is much better than tube and fin. Install the external cooler so the oil coming from the trans goes through the external cooler first then into the OEM cooler before returning back to the transmission.

perZ

Thank you AlkyIROC That sounds very sensible, good to know! I checked my cooler last night and did find the pipes leading to the cooler, so they seem to be installed like stock.


My question came from me thinking that the tranny temp gauge was showing too high temperature sometimes when driving in town. It passed 180F even though not by far since I then took the highway. Don't know how hot it would become if I continue driving in town longer though. It shouldn't go much above 180F with a stock car if everything is okay, right?

perZ

By the way. When I went to look for the transmission cooling pipes I also wanted to check up on a recently discovered oil leak... follow the link to see what I found.


https://www.thirdgen.org/forums/tran...ml#post5932541


Bad news

Fast355

iTrader: (2)

Myself and GM prefers the opposite arrangement. Run th hot fluid into the radiator cooler, then into the external cooler. My 4L80E Express was setup this way from the factory

perZ

Okay, lots of information in different directions at the moment Will think it through if tranny temp keeps going up. Cheers!

Night rider327

iTrader: (13)

175-195* is normal temp range for an auto trans.

200-210* is the high caution zone

Real bad things start to happen at 240*

AlkyIROC

Depends where the temp sensor is installed. In a line means the oil is under pressure. Coming from the trans, it's going to be hot. Returning from the coolers, it's going to be less hot but still under pressure.

The best place to measure the temperature is in the pan. The oil is not under pressure. It's finished working through the hydraulic circuits and is waiting to be picked up by the pump.

As mentioned above, 180* is nothing. Above 240* and it's starting to get a little too hot. By the time is hits 300*, it's cooked.

Switching to synthetic oil can also help keep the temperature lower.

morgsie

iTrader: (1)

I believe most if not all auto manufacturers do it this way as well. That's why it's always referred to as an AUXILIARY cooler in most factory literature. I'd only run it the opposite way if vehicle was operating in very cold climate.

perZ

Thanks again guys for good and a bit calming information My temp sensor looks to be placed in the pan (not installed by me), so seems like the right spot then.


Cheers,
Per