74/75 Ford L6000 with cat 3208

[born2ride]

Questions on my Ford L6000 with a cat 3208, Looking for the temperature gauge sending unit, My gauge reads cold always , so i grounded gauge and it sweeps up , Ohm out sensor and its open .I went to my local napa ,they have no listing, Looking for a place to get this sensor.

Last question is what type of transmission fluid does this truck take? I think its and Allison unit , but not sure!

 

[Jonas302]

The sensor is more likely ford than cat call your ford truck dealer with the vin and see if they still have one if you don't know of a Ford heavy truck dealer you could try Boyer in Minneapolis http://www.boyertrucks.com/map-and-directions-dealership--hours-minneapolis they will ship it to you if available If not available you could install a new universal style from napa

 

[Birken Vogt]

I have a fingernail that grows weird from that exact sensor. Attempting to remove it, applying "tons" of force, by hand, rounded off, absolutely crushed fingertip against whatever that cast iron thing is in upper top of picture. (Don't remember details 15 years ago but finger remembers)

My experience with old Ford parts support has been bad to worse so I might just attempt to put in a sensor from a pickup about the same year and see what happens. Or you could try various resistors and see what makes it do what you want. I don't remember where I got mine from.

As for the transmission, is there no tag on it? Iron or aluminum case? What does the fluid in it look like?

 

[Truck Shop]

Install a temp sensor from a mid 70's pick-up. The headlight switch and I think the heater switch is the same. {and the horn button from a falcon**

Truck Shop

 

[born2ride]

As for the transmission, is there no tag on it? Iron or aluminum case? What does the fluid in it look like?

Finally got around to crawling under this thing to see that unit looks like. i did see a flat spot where a tag would be on right rear side of unit but nothing there! hope the pics help

 

[RZucker]

Allison Mt 653.

 

[Birken Vogt]

That will be a MT65x Allison transmission. It was still made up to not too long ago. It has a granny low section bolted on the end of it which makes it a 5 speed. But there are usually only 4 progressive speeds, 2nd through 5th and low is selected manually.

Anyway, it can take either motor oil or regular ATF. You don't want to mix the two.

That is why I ask what it looks like. If it is ATF then stick with that. If it is motor oil then stick with that.

 

[born2ride]

Thanks! Motor oil in a trans lol Guess trucks are different that cars. Been at a ford dealer many years never saw a unit with motor oil..
Are they durable units? what is that box attached to lever?

 

[Birken Vogt]

Back in the day motor oil was better for severe heat than ATF so it was on the OK list to use for transmissions is what I have been told. I have never seen it either but I have seen it in the manuals. It seems that if you were running at extreme temperatures for long periods you might choose motor oil. If motor oil is in it, then the minimum operating temperature is much higher than ATF.

The box on the side is part of the modulator. It should be connected to the throttle linkage. So that the transmission shifts at higher RPM when the throttle is pushed in further.

 

[RZucker]

Back in the day motor oil was better for severe heat than ATF so it was on the OK list to use for transmissions is what I have been told. I have never seen it either but I have seen it in the manuals. It seems that if you were running at extreme temperatures for long periods you might choose motor oil. If motor oil is in it, then the minimum operating temperature is much higher than ATF.

The box on the side is part of the modulator. It should be connected to the throttle linkage. So that the transmission shifts at higher RPM when the throttle is pushed in further.

When engine oil was recommended, It was a straight weight oil with an Alisson C2 rating. Multi-vis oils were a no-no, or so I was told. Most AT and MT transmissions do fine on Dexron2 if the loadings aren't extreme. Usually after a rebuild I recommend the synthetic Transynd oil, but the system needs to be completely flushed as it won't play well with petro oils.
I do have one customer using John Deere HY Gard in HT 750's with good results. And another customer running 30 wt C2 rated engine oil in the big 5000 series scraper transmissions in the summer, they seem to run cooler. Probably from less convertor slippage.

 

[Birken Vogt]

I dug around in my computer and found the 1999 Allison Mechanics Tips for this transmission. They allow 15W-40 in that document, along with all the others.

I have seen a document from Allison on the Transynd and they don't worry about flushing it. They just specify the number of changes required before you can do maintenance intervals that apply to full synthetic.

But as far as the OP goes, from the mid 1970s I doubt he is interested in the expense of Transynd or anything else. I am just trying to give him an idea on the most economical way to go on driving his truck.

 

[born2ride]

This unit has harsh and sometime it seems stacked on downshift. Anything i can check adjustment wise?

any pdf s manuals on that trans?

How many different models of that MT65?? did they make?

 

[Birken Vogt]

They are not particularly smooth, especially if unloaded.

The class instructor always said, question #1: what is the oil level?

Oil level checked hot at idle like any automatic.

 

[born2ride]

They are not particularly smooth, especially if unloaded.

The class instructor always said, question #1: what is the oil level?

Oil level checked hot at idle like any automatic.

Low! Thats why I asked what type of fluid it took!

 

[Birken Vogt]

Whatever is already in it. If it is ATF then any name brand ATF will have Allison rating on it. If it is motor oil, most truck type oils are C4 rated, or used to be. I haven't looked post-low-sulfur to see if that changed.