Lehman Transmission Cooler Installation Problems

[Oil Gypsy]

Hello.


I'm hoping someone can point me in the right direction with an issue I'm having installing a new transmission oil cooler on my Ford Lehman 120. I removed the old cooler at the end of last year but due to a pretty serious hand injury (unrelated) Ive only just been able to get back to putting things back together,


When I removed the old cooler one end came apart as I was removing the hose from the main heat exchanger (See Photo #1), at the time I thought it was a fault with the unit. Now that I'm trying to reassemble I cannot align the connection from the heat-exchanger to the inlet of the transmission cooler. If I use the transmission cooler bracket attachment point ( Photo #2) on the on the bell housing the misalignment is significant (Photo #3 - maybe this is why the original cooler failed), I have also tried attaching the cooler bracket to one of the bolts securing the bell housing to the engine (Photo 2 - Bolt above and left of bracket securing point), this reduces the misalignment but does not remove it completely (Photo #4), this also introduces another problem, the cooler and the heat exchanger are in contact and I'm sure it wasn't designed for this to happen.

The main heat exchanger is original to the engine and bolts onto the back of the head, there is no way to change the way it sits on the engine, I cannot see any other way to attach the transmission cooler. I assume I'm doing something wrong but cant see what so any help would be greatly appreciated.

 

[C lectric]

I am going to suggest you take and post a few more photos that show from farther back so we can see a wider range and see relationships to other things.

What about the clamp that holds the cooler. Is it twisted? Can it be twisted?

What about sliding the cooler towards the nipple on the left, photo # 4.
THen that lost space could be used on the other end to help get a better alignement at the other end using a longer piece of hose.

I ran into something like this last year and resolved it by using Silicone hose I got from Greenline Hose through my local distributor. It is much more flexible and can withstand higher temps. Just use AWAB clamps to protect the hose.

My problem was on my Raw water pump and the slightly angled hose was no longer available as a Cummins part number.

 

[Nick F]

Bill - I had exactly the same problem when re-installing my (new) transmission cooler. It drove me nuts! I also looked at the Ford Lehman on another boat in our marina and discovered that its transmission cooler was contacting the main heat exchanger. I ended up solving the problem by adding a spacer to the clamp that holds the transmission cooler (see photos).

Good luck!
Nick

 

[Cigatoo]

Seems to me longer or shorter hoses (where necessary) and then moving the cooler around using spacers and the like will allow you to get things lined up properly. You don’t want any consistent strains or un natural bends in the hoses as they will eventually leak at the worst possible time. Thinking out loud, That trans cooler could theoretically be placed pretty much anywhere. Of course this is easy to say sitting here drinking my coffee.

 

[Alisske]

Yeah. Mine had a spacer in the bolt running into the bell housing and it was also canted (see pic). When I installed a new heat exchanger, i said to myself “im gonna fix this and make it straight etc..”

Well, after didling with a week, the original orientation an installation was the only one that worked for me, lol.

Hope this helps

 

[Nick F]

I have seen the cooler mounted skew as well - really offends me (must be going OCD!).
I am going to the boat today and will try to remember to take some more photos to show how I managed to mount it parallel without touching the main exchanger.

I see that the raw water inlet to the main exchanger is oriented differently on Alisske´s engine, so it may be that for some main exchangers it is not possible to avoid skewing the tran cooler to avoid contact.

Nick

 

[SteveK]

Is it possible the clamp attachment is reversed. Away from boat but I know mine sits parallel to the main cooler

 

[Oil Gypsy]

Thank you everyone for the replies, I really thought I was making a mistake in the way I was putting it together. My first impression was that the outlet from the engine heat exchanger had been damaged/bent but this isn't the case.

If the transmission cooler is connected to the correct mounting point on the bell housing then it looks like the outlet from the heat exchanger needs to be extended about 1.5".

I must admit that I also suffer from more than my fare share of OCD, knowing its not right will bug me forever more. Extending the bracket will help and I need to have a look at how much I can move the cooler to port to fit a longer hose. I like the idea of a silicon hose as these appear far more flexible.

Once again thanks for taking the time to reply and confirm that I'm not installing everything upside down and back to front...

 

[Nick F]

Took some photos - but left the camera on the boat!

The elbow to the tran cooler measures 1-5/16" from centreline of the elbow outlet to the surface of the main exchanger. This elbow, on my engine, is at the 9 o´clock position when looking from stbd towards port, whereas yours appears to be at about 7:30.

The greatest outside diameter of my tran cooler is about 2-1/8", so it is possible for my cooler to line up with the exchanger outlet and remain parallel to the exchanger, without contact.

 

[Nick F]

Here are the pictures of my cooler and the main heat exchanger. Hope this helps.

Nick

 

[Oil Gypsy]

Finally managed to get it sorted, I copied Nicks solution. I used 1/8th inch Stainless for the bracket, I made several, each with different hole spacing (cheaper to have several to try than to drive to the boat each time I wanted a different size), in the end it was the smallest, with 3/4" center to center that provided the best alignment. The two coolers are lined up and the hose connections are almost perfectly in line. Good enough.

Again thanks for all who commented.

 

[RT Firefly]

Greetings,
Mr. OG. Atta' boy!!!!

 

[Nick F]

Great - glad it worked out !
Regards,
Nick

 

[Nepidae]

120n Lehman cooler replacement

STOP, STOP, STOP.

Do not do anything until you talk to Brian at American Diesel. HE IS THE ONLY EXPERT on Lehman engines.

He also has the parts you need.

He is also VERY helpful.

Here (https://americandieselcorp.com/) is the site to get a phone number.

Following instructions from anyone else will probably leave you unhappy.

As Andy Taylor once said to Aunt Bee, call the man.

 

[Tator]

Can't be Aunt Bee! Or-Oh Andy, don't you think your being a little hard on the boy?

Tator

 

[Nepidae]

I think you missed that one.

It was Leave it to Beaver when June said to Ward, you were a little hard on the Beaver last night.