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250 or 270 or 280

J

jeffnick

Regular Contributor
The cover on my outdrive says 250. I tried to replace that transmission with one that was sold as a 250. It didn't fit. What did fit was a trans that was sold as a 280 and yes I reshimmed it to .003 squish. Soooo, I'm guessing my outdrive is not a 250, at least the intermediate section and the trans aren't 250. Could I still have a lower 1/3 that is from a 250? Is there any way to tell?

Also, the (dark) trans from the 280 which I put in, has a plug at the upper right, that the (white) one I took out doesn't have. Is there something I need to know about the plug?
trans-b.jpgtrans-a.jpg

I'm planning to go through the white trans to see why it's very slow getting into forward gear - reverse is OK. I've read the threads on what to look for and what 'repairs' to make.

BTW - thanks for the tip on removing only the transmission.
trans-c.jpg
 
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jeffnick said:
The cover on my outdrive says 250.
All of the older shift mechanism covers of this style will interchange.
Someone replaced yours with a 250 cover.

I tried to replace that transmission with one that was sold as a 250. It didn't fit.
You'll see 3 driven gear bearing sizes with these AQ series transmissions.
The 250 used the small bearing.

What did fit was a trans that was sold as a 280 and yes I re-shimmed it to .003 squish.
Good!

Soooo, I'm guessing my outdrive is not a 250, at least the intermediate section and the trans aren't 250.
I can't see the lower gear unit, but I'd say that the transmission and Intermediate housing are NOT a 250.

Could I still have a lower 1/3 that is from a 250?Possibly! Is there any way to tell?
Yes!
The 250 Intermediate housing will have a oil port just below the shift mechanism cover.... anything past that, will NOT.
The 250 Intermediate housing will NOT accept a 280 transmission!
The 250 lower gear unit uses bevel cut gears...... not Hypoid!

Also, the (dark) trans from the 280 which I put in, has a plug at the upper right, that the (white) one I took out doesn't have.
The oil fill port first came out with the 280 transmission. All since then have it.

Is there something I need to know about the plug?
That is where you add the new 30W engine oil...... NOT heavy gear oil!

View attachment 25037View attachment 25038

I'm planning to go through the white trans to see why it's very slow getting into forward gear - reverse is OK.
Most likely caused by metallic debris within the oiling groves of the bronze sliding sleeve.
If you are going to disassemble it, post back, and I can tell you what needs to be done.

I've read the threads on what to look for and what 'repairs' to make.

BTW - thanks for the tip on removing only the transmission.
Much easier, isn't it?

View attachment 25039
Click to expand...
 
You are welcome.


Tip......
When removing the transmission, and when you reach this point........

attachment.php


..... lift up just enough to disengage the spline coupler, and turn the transmission sideways 90 degrees.
It will be easier to remove!

Do the reverse of this when going back together.
 
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jeffnick said:
Follow up to the transmission swap...it went fine. I took some pics for a buddy who thinks he wants to install his entire 280 out drive in one piece.
Some one needs to show him how much easier it is to install the transmission last.


Ricardo - did I leave anything out?
https://tinyurl.com/y5y2vhe2


Well done!

Just a few FYIs...

..... regarding transmission mounting..... the two nyloc nuts and the two cap screws are 3/8" NC

...... it's much easier to allow the vertical shaft spline coupler to drop down into the Intermediate housing while you remove the transmission.

..... perhaps mention that there are 3 different transmission driven gear bearing diameters.

200/250 are the smallest
270 thru the first gen SP transmissions are mid size
C and later are large diameter.

These will not interchange.
Click to expand...
 
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