Automatic Tranny Question

[madpaddler]

Not that I am having any great issues with mine other than the normal leak points, but I was noticing on parts lists, return lines that go from the tranny to the radiator...mine has no such lines (hoses) and was wondering if this was a mod that was made to the original for any particular reason? Would like to know if I need to find a set and hook this feature back up or was this deleted for a good reason. Mine is a 73 if it matters

Thanks as always for the feedback, the forum and people are great.

[jerry]

i posed this question to my local radiator guy who knows 02's since 'back in the day' and has done quite a bit of 3-core work. i brought him an automatic radiator to recore and his comment to me was that the coolant flow through the inlet and outlet at the bottom was VERY restricted due to internal baffles. he followed up by showing me the internals once he had it disassembled and there really is an inherent obstruction in front of the inlet and outlet ports.

bottom line, don't expect much coolent flow through the lines. the fact that yours has functioned fine without them should be a testimony to the minimal utility of them.

however, if you like things the way the factory intended (as i'm guilty of), then there's no harm in re-installing them. i will, when the time comes...

[PatAllen]

words of caution for theses 3HP12...

the oil cooling lines on theses are the overflow from the pump, dumped to the pan directly, not the inlet or outlet presure of the pump at all. if the trany has high mileage and the pump started to loose presure, it is actualy helping to raise the presure a bit to install such oem oil cooler...ask me how i know.

I did install a oem cooler on my Automatic last summer. I used every single tidbits from a donor Automatic with the cooler lines and rad. Easy to do and worth the time and money to do it.

The line and cooler also hold some more oil (maybe one more quart ?) so it also help there for oil starvation under high g's

Look at this post for pictures and details:

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,343241/highlight,cooler/

[madpaddler]

Hey thanks Pat. I picked up a spare trans from a local guy and noticed the lines on that one and knew mine did not have any. What have you notice that makes it worth the effort to install? Improvement in performance of you trans? Or piece of mind that the unit is kept cooler than without? Thanks for all the great info!

Hal

[PatAllen]

I made it for several good reasons.

1-it cannot hurt to have one. The opposite might not be true.

2-my tranny was suffering of a weird problem, after several kick-down or moderate abuse/acceleration, it wouldnt shift in third, it required some cool-down to happen again. Oil was foaming ? overheating ? i will never know. I assumed it was overheating.

3-for the peace of mind at 99%.

I installed the oil cooler set-up and poured in a Lucas trany fix (the heavy thick stuff).

Never had a problem since then.

[madpaddler]

Jerry,

thanks for the info, no telling how long my existing set up without the coolant hoses has been missing. I have had the issue once or twice as Pat describes having an issue going into third when everything is running hot....may try that thick stuff he mentions and may put the lines from a donor on to see if I notice anything. Thanks to you both for good info.

Hal

[02for2]

i posed this question to my local radiator guy who knows 02's since 'back in the day' and has done quite a bit of 3-core work. i brought him an automatic radiator to recore and his comment to me was that the coolant flow through the inlet and outlet at the bottom was VERY restricted due to internal baffles...bottom line, don't expect much coolent flow through the lines...

If I'm reading you right, you have it backwards.

The coolant doesn't flow to the tranny, it's the tranny fluid which flows through the radiator and back.

It is fairly effective and as Pat points out, adds somewhere between .8 and 1.0 Qts. of additional fluid capacity - a good thing.

Cheers!