4hp22 gurus.....

[slammin_e28]

...anyone know the pressure the trans fluid should be at when in the cooler lines?

I keep blowing lines in the Range Rover w/52. Had the lines spliced together with some ATF hose, lasted like a year and came apart. Then I flared the ends of the cooler pipe and re-installed the hose, and it lasted like 6 months. So I got some spare lines and MIG'd them together to rid myself of the rubber splice....and it popped a pinhole in the metal line was when it was idling.

SRSLY? It can't be under that much pressure, can it?

[waynet1]

Well, we could guess all day long, and then some. My guess would be, no more than 30psi, and probably more like 15.
Sounds more like a vibration or chafe issue to me.

I would think Range Rover would know the answer to the pressure question.

Edit:
Another question altogether would be; how much pressure are they capable of, if the cooler is blocked ?

[tn535i]

See if the pressures are in this link, something I found when I did the A clutch rebuild on one of mine.
http://www.jaguarclub.sk/service/powert ... -%20zf.pdf

[Mike W.]

I've got some detailed 4HP info at home, but it'll be tomorrow night before I get a chance to possibly look for it. Ping me if you're still looking and I forget.

[mooseheadm5]

He'll still be looking. The only things I can think of are a blocked cooler or the chafing vibration thing. I have repaired bad 4HP cooler lines with hose and clamps and the repairs have lasted longer than the cars.

[wkohler]

On the 745i I parted, the cooler lines were hooked to a tube atop the rad with hose clamps and let's just say they weren't busted.

[winfred]

it ain't much, which is useful as shitty as the coolers are, make sure you are using cooler line for the splice, anything else turns into shit, as for dobbing the lines together with a welder they are usually pretty thin and not made from awesome steel

[slammin_e28]

See if the pressures are in this link, something I found when I did the A clutch rebuild on one of mine.
http://www.jaguarclub.sk/service/powert ... -%20zf.pdf

I found that while searching too. Bookmarked it after reading through it. Was at work, so didn't get a chance to actually read it, but skimming I didn't see anything.



This is the line. I MIG'd it again last night. Big time. Instead of going around the splice, I welded horizontal to the splice. It's not pretty, but it's not leaking.

Again, should have TIG'd, but with a supposed 5" of snow...eh, rain, bearing down, I wanted my big 4x4, just in case, since everything else had shit for summer tires.

It's just the one line, with the sensor in it, but I know BMWs don't have a sensor. There is one that comes out under the trans, then the one that comes out up on the left side. It's the upper one that keeps blowing. The other one has been fine with cooler hose (yes made sure it was the proper hose to handle ATF) and clamps.

When I have time I may just take the entire system apart and see what's what. Maybe an aftermarket cooler. My radiator is starting to show some blue (BMW coolant) on the side, so I'll have to replaces that at some point too.

[Mike W.]

Brazing is really much better for stuff like this than welding. It's plenty strong enough and you are flowing metal on rather than melting it with the risk of pinholes and slag. Either brass or silver solder or silfloss work great. You would need to overlap it some though, not just a butt splice so to speak. But even copper tubing will hold a couple of hundred PSI.

[slammin_e28]

So googling around and what not, also checking the Jag service manual, I came to this:

Unit pressures:

Drive, stationary: 630-710Kpa (92-103PSI)

Reverse, stationary: 1070-1150Kpa (156-167PSI)

I'm guessing this is internal, and not what the lines are handling, but it's about all I got.

I was looking for a fluid flow diagram, because it seems the one lines has been fine being clamped hose, etc....and came upon this:

http://www.defendersource.com/faq/Trans ... tml#Filter

"Upon torque converter lock up, the pressures in the cooler lines go to 60-70 psi"

Also:

"According to the engineers at ZF, in the mechanical version (like ours) the fluid flow in the cooler lines DOES reverse when the torque converter locks up"

"The 'Cooler Return Line Chart' link also identifies the line coming into the bottom of the trans just behind the bell housing, as the return line. I guess this means in normal operation, as the flow reverses on torque converter lock up."

So, the one I have problems with is, under normal conditions (ie: not TC lockup) the pressure line to the cooler. I would think though, that when the TC is locked up, and I'm blasting 65-70mph on the highway, the return like would pop, since the fluid is reversed?

So, I guess I have my answer.

Now, is there any difference in a 524td TC over a normal M20 TC? I heard they are a higher stall, but I've got on kicking around, and need a rear main seal, so would it be worth it to throw it in there?

(To keep it relevant, I'm assuming this is the same for e28 4hps.....don't see why it'd be different....but who knows?)

[waynet1]

"According to the engineers at ZF, in the mechanical version (like ours) the fluid flow in the cooler lines DOES reverse when the torque converter locks up"

I have an extremely hard time believing that.
If that's the case, then the E28 radiator transmission cooler will be acting as a heater, not a cooler.

I'm not from Missouri, however..............

[slammin_e28]

"According to the engineers at ZF, in the mechanical version (like ours) the fluid flow in the cooler lines DOES reverse when the torque converter locks up"

I have an extremely hard time believing that.
If that's the case, then the E28 radiator transmission cooler will be acting as a heater, not a cooler.

I'm not from Missouri, however..............

Actually wouldn't it cool from either direction? It just needs to go through the cooler. Doesn't care which way.

Anywho, I think I fixed the leak. As long as it gets me through Winter I'll be happy. Going to build my own cooling system for it come spring. Temp and pressure sensors, bigger cooler, going to be schweet.

Still can't believe it's under that much pressure. Oh well. I've been monitoring the fluid level and it hasn't budged since I repaired it.

[waynet1]

"According to the engineers at ZF, in the mechanical version (like ours) the fluid flow in the cooler lines DOES reverse when the torque converter locks up"

I have an extremely hard time believing that.
If that's the case, then the E28 radiator transmission cooler will be acting as a heater, not a cooler.

I'm not from Missouri, however..............

Actually wouldn't it cool from either direction? It just needs to go through the cooler. Doesn't care which way.

In a stand alone cooler, yes, it would cool the same in either direction.
But the along the side, top to bottom, cooler in the radiator would be a different story. Hot on top, cooler on bottom. Reverse the flow and...........

That's my theory and I'm stick'n to it