83 w123 300TD sedan diff swap

[stephenc1984]

I live on an island where the top speed is 25MPH. Steep winding roads that are mainly unpaved. I saved the 83 sedan out of the junk yard and have been harvesting engine and other misc parts over the last few years. It needs a new engine which I have. I need lower gears for the hills. I was thinking of swapping the diff for a 240D diff(3.69?) to achieve that. By swapping the diff for lower gears, how does that effect the shifting/vacuum components of the automatic trans? Realistically it would probably only need one shift to get to 25MPH maybe two. Also, I know that the auto trans starts in second gear even when the "L" position is selected. Are there anyways to make the trans start in first?

[t walgamuth]

I don't believe that is a second gear start year. If it is, yes there is a way to make it start in first. Unless you have tremendously steep hills the gearing should be fine I'd think especially with an automatic. If you put in a 369 you'll probably make first gear useless. An intermediate solution would be a 354 from a 300 na. I'd probably at least try it out with the stock gearing before going to the effort to change it.

[stephenc1984]

Originally Posted by t walgamuth

I don't believe that is a second gear start year. If it is, yes there is a way to make it start in first. Unless you have tremendously steep hills the gearing should be fine I'd think especially with an automatic. If you put in a 369 you'll probably make first gear useless. An intermediate solution would be a 354 from a 300 na. I'd probably at least try it out with the stock gearing before going to the effort to change it.

I don't know what you define as "tremendously steep," the car would be climbing 1500 feet in 1.75 miles with a lot of sharp turns. I will try the stock diff and see how she performs. I have a fully equipped shop so changing out the diff will be easy if and when I decide to do that.

[Graham]

Sounds like an interesting place to live!

Question: Is your shop at top or bottom of mountain

[stephenc1984]

[QUOTE=Graham;3808788]Sounds like an interesting place to live!

Question: Is your shop at top or bottom of mountain [/QUOTE
The shop is at the bottom of the hill.

[Frank Reiner]

Originally Posted by stephenc1984

I live on an island where the top speed is 25MPH. Steep winding roads that are mainly unpaved. I saved the 83 sedan out of the junk yard and have been harvesting engine and other misc parts over the last few years. It needs a new engine which I have. I need lower gears for the hills. I was thinking of swapping the diff for a 240D diff(3.69?) to achieve that. By swapping the diff for lower gears, how does that effect the shifting/vacuum components of the automatic trans? Realistically it would probably only need one shift to get to 25MPH maybe two. Also, I know that the auto trans starts in second gear even when the "L" position is selected. Are there anyways to make the trans start in first?

1) What is the current final drive ratio? Stamped into lower corner of the rear face of the main diff housing. Shifting will not be affected by a change of final drive ratio; the shifts will simply occur at a different road speed. [W114/115 cars with various engine installations had 3.92:1 gearing. I have one, should it not be found elsewhere.]

2) What is the transmission model? A string of numbers stamped into the right side pan rail just above the pan gasket surface.

[stephenc1984]

Originally Posted by Frank Reiner

1) What is the current final drive ratio? Stamped into lower corner of the rear face of the main diff housing. Shifting will not be affected by a change of final drive ratio; the shifts will simply occur at a different road speed. [W114/115 cars with various engine installations had 3.92:1 gearing. I have one, should it not be found elsewhere.]

2) What is the transmission model? A string of numbers stamped into the right side pan rail just above the pan gasket surface.

I thought all the turbo diesels had a 3.08. I dod not know there were different transmissions for the w123 turbos.

[t walgamuth]

Originally Posted by stephenc1984

I thought all the turbo diesels had a 3.08. I dod not know there were different transmissions for the w123 turbos.

Yeah, all turbos came with the 308 from the factory, but the diffs are very interchangible through a good many years.

[okyoureabeast]

I didn't know there were islands big enough in Temecula!

I kid, sounds like you're one of the lucky few who own a real car in Avalon. Best of luck for your project!

[stephenc1984]

Originally Posted by okyoureabeast

I didn't know there were islands big enough in Temecula!

I kid, sounds like you're one of the lucky few who own a real car in Avalon. Best of luck for your project!

The car is in Temecula, I live in Avalon. Scheming to get it here.