Fairey OD help needed

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Feb 27, 2013
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Oakesdale WA
Ok so here at the local parts store they have 80w-90 and 85w-140. Would the 85w-140 give me good cold weather performance AND a heavier oil to help with noise? Also...is synthetic good/better in these older gear boxes??
 
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If you have not already done so, now might be a good time to read up on the differences between GL-4 and GL-5 gear oil. Someone will correct me if I'm wrong, but I believe that GL-4 is the recommended type for our older cruisers. Not easy to find at the local parts store. For example, here is one
 
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Alright @Living in the Past I will check that. I'll try to take a picture of the plug that I pulled to fill the unit. It DEFINITELY looked exactly like a drain/fill plug.


Did you ever get a pictures. All my Fairey Overdrives are boxed up at another location. I was hoping to be at that location today. Not going to happen this week. I can't remember a fill plug in the cover. Remember the screw that holds the spring loaded ball that keeps the shaft with the shift fork in place. Then the shaft for the lever used to move the fork . The end is a steel plate that had a cage bearing on the inside but no fill plug. See the link mentioned a fill plug but not finding it in the diagrams. Also missing a page of part numbers. No of my ODs came with a manual in fair condition. Remember a page of part numbers was missing. Need to check that when I check my ODs. In the same location.
 
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@Living in the Past
Here is a picture looking from the back of the transfer case. The fill plug is right next to the words cast in the housing. There's a copper crush washer under the plug...looks like I need to replace it. It sure looks higher than the fill hole for the transfer case so not sure how that works if they share the same oil....

20221005_183823.jpg
 
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@Living in the Past
Here is a picture looking from the back of the transfer case. The fill plug is right next to the words cast in the housing. There's a copper crush washer under the plug...looks like I need to replace it. It sure looks higher than the fill hole for the transfer case so not sure how that works if they share the same oil....

View attachment 3133124

Now I'm really curious to look at mine. Obvious that is your oil fill. Think I still four of these housings stored away. Did noticed that the manual linked for four speed. How the opening for the lever used screws on the transmission and transfer case boots for reference are for the four speed. Never seen a copy of manual for the three speed.

Have a question, how close is the OD to the torque tube behind it? The 73 was the first year the FJ40 was made to clear a four speed. Thought a four speed with the Fairey OD would fit. Also is there another threaded hole in the frame behind the skid plate? My 73 has the fourth hole for the four speed skid plate.
 
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I got the vehicle on jack stands on the right side but didn't have time to actually do anything else last night other than take the picture. I've never looked at one of these units on a bench (in fact I didn't even know they existed until I bought this FJ40) so I'm not sure how to proceed, but would it be possible to pull that round steel cover off the back and inspect the inside (shift fork, syncro, etc)? It looks like just a cover with a few bolts but maybe it holds a bearing to support the back of the shaft? Can I drop the lower half of the housing without causing problems? Just curious how much I can do without actually pulling the doghouse.

My guess is that it is gummed up for sitting 20 years. I'm not sure if there's any rust or corrosion on the section that was above the oil level so I'm thinking I might need to have a peek inside to verify.

On the oil topic.....I checked the barrel and the stuff I have in it is Quaker State SAE 75w-90 GL-4 gear lube. I'm hoping I just don't have enough oil in the unit but we'll see.

gearoil.jpg
 
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Now I'm really curious to look at mine. Obvious that is your oil fill. Think I still four of these housings stored away. Did noticed that the manual linked for four speed. How the opening for the lever used screws on the transmission and transfer case boots for reference are for the four speed. Never seen a copy of manual for the three speed.

Have a question, how close is the OD to the torque tube behind it? The 73 was the first year the FJ40 was made to clear a four speed. Thought a four speed with the Fairey OD would fit. Also is there another threaded hole in the frame behind the skid plate? My 73 has the fourth hole for the four speed skid plate.
@Living in the Past Funny you should mention the cross member. I noticed that it has been cut out and re-welded (not very well I might add) and I assume that was when the dealership installed the OD. I'm probably going to re-do it with sleeves on both ends at some point. Even though this FJ40 is going to be a pavement queen I think the cross member is important enough to be done right.

I'll post a picture when I get under there again.
 
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@Living in the Past Funny you should mention the cross member. I noticed that it has been cut out and re-welded (not very well I might add) and I assume that was when the dealership installed the OD. I'm probably going to re-do it with sleeves on both ends at some point. Even though this FJ40 is going to be a pavement queen I think the cross member is important enough to be done right.

I'll post a picture when I get under there again.


Interesting about your torque tube/crossmember. Since the 73 was made for a four speed which is three and a half inches longer than the three speed the OD should fit with a three speed. It wasn't until the 79 model that Fairey literature said the OD would not fit in a FJ40. Fuel tank moved under the tub and went from 16 1/2 gallons to 22 1/2 gallons and clearance was a problem. Fairey showed it only fitting the FJ55 in 79 and 80. I have verified the three and four speed skid plate fit my 2/73 FJ40. Three uses the first three fitted nuts and four speed moves back on used 2nd thru fourth fixed nuts. Guess I need to verify the torque tube location on my 2/73 and 10/75 FJ40s. I know the transmission covers from 9/72-1/79 will interchange with each other.
 

Ming89FJ62

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pb4ugo

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I don't know anything about the Fairy overdrive, but looking at the pics and glancing at the manual it appears the O/D unit has a reservoir to hold gear lube,
so the idler shaft bearings are lubricated.
 
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you're in luck - 3-Speed it it

In the the US all 73 FJ40s had a three speed. Early 74s also had a three speed. I need to measure my early 76 FJ40 and 73 to see the if the location of the torque is the same. If there are a Fairey OD should fit with a four speed. I've had my 73 for twenty eight years and have never even started it. It was actually offered to me out of the blue at a price I couldn't pass up. I couldn't buy OEM soft top bows and soft doors for what I paid for the whole vehicle. Having driven bought the J30 three speed and H42 four speed the will take the four speed over the three speed.


@Living in the Past If I'm looking at the parts drawings right it looks like #38 is the fill plug??
[/QUOTE]


In the mix of those is a spring and steel ball. The shaft has cutouts that lock the collar that switches the OD. The spring loaded ball is what does that. The new link is also for a four speed. Can see the picture is a four speed. Same with the locating the cut out in the tunnel cover. Toyota had a PTO gear in the mid 63 to early 74 in the US market. As a result believe all Fairey Overdrives sold for three speeds in the US had the PTO gear. Four speeds have a spacer. Have yet to see a listing for a PTO gear in any diagrams. Shows up as #13 PTO spacer. Betting your three speed OD has the PTO gear. Unlike Toyota's PTO gear the one inside the OD works in either the three speed or the four speed. I've had three three speed Fairey Overdrives all have had the PTO gear. All four speeds the spacer.
 
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Here's something I find interesting in the manual that @Ming89FJ62 posted above. It states on another page of the manual that the oil is shared, but step 52 says to fill the gearbox and transfer case and then step 53 says to fill the OD as well. Just something I found interesting.

1665084036791.png


I stopped by the local transmission repair shop and explained the situation. They have worked on a few OD's on Jeeps but never an FJ40 unit specifically. His suggestion was to drain the transfer/OD and refill with solvent. Then drive it around town, park it and let it sit, then repeat a few times and it should free everything up. Then drain the solvent and refill with GL-4 gear oil. He expects the detent is gummed up from sitting for 20 years and bathing it in solvent will free it up.

I'll post whatever happens here on this thread.
 

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