lube for 7.5" ford rearend

Jun 9, 2011
140
19
romulus ny,usa
For all you folks with the ford rearend. How full is full as far as how much lube to put in? Motortrike manual says 3.3 pts,and also says to within 1/4 to 3/8 inch of fill hole??? 3.3 pts doesn't come close to the fill hole. Acually 2 qts doesn't come close to the fill hole. So what is the right answer?
 
Perhaps the Motortrike service manual will help. There is a PDF Motortrike service manual in this this link. Perhaps it will give you the answers you need: <a href="http://www.triketalk.com/forum/honda-trikes/315-motor-trike-service-manual-finished.html" target="_blank">http://www.triketalk.com/forum/honda...-finished.html</a>
 
Thanks Nana, but thats where I got the info I was asking about in my post. The manual has conflicting info. I was just woundering what others here are doing.
 
Same confusion with the Suzuki/Lehman trike I've been working on. Ford (of some sort) rear differential. The Lehman online pdf. manual doesn't offer any capacity spec, just says to "check rear differential fluid regularly". After 9 yrs. without any real servicing (yes, maintenance was embarrassingly neglected) decided I'd better check it. <br />
<br />
Removed the level plug and added hypoid fluid until it j-u-s-t started dripping out of the level plug hole........it took 2.8 QTS.!!! YIKES!!! Owner said it rides much better now (there's a big surprise, LOL! Lucky the rear-end didn't go south)<br />
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Venturing a guess here.......is it possible that the Motortrike spec is a misprint ?

Instead of 3.3 pts., could they mean 3.3 QTS. ?
 
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<img src="images/misc/quote_icon.png" alt="Quote" /> Originally Posted by <strong>Ol' Grey</strong>
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<div class="message">Same confusion with the Suzuki/Lehman trike I've been working on. Ford (of some sort) rear differential. The Lehman online pdf. manual doesn't offer any capacity spec, just says to "check rear differential fluid regularly". After 9 yrs. without any real servicing (yes, maintenance was embarrassingly neglected) decided I'd better check it. <br />
<br />
Removed the level plug and added hypoid fluid until it j-u-s-t started dripping out of the level plug hole........it took 2.8 QTS.!!! YIKES!!! Owner said it rides much better now (there's a big surprise, LOL! Lucky the rear-end didn't go south)<br />
<br />
Venturing a guess here.......is it possible that the Motortrike spec is a misprint ?

Instead of 3.3 pts., could they mean 3.3 QTS. ?</div>

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</div>I was thinking the same thing. I remember back in the good old days when all cars were rear wheel drive,anytime we added lube to the rear ends,you allways filled it to the fill hole.
 
Yep it is a typo,,, <img src="images/smilies/redface.gif" border="0" alt="" title="Blush" class="inlineimg" /><br />
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Fill it up to just before it runs out. Now just like mentioned above just a trickle would be good. In the old days when checking the rear end I put my pinky in the hole, and crooked it down, and if it got lube on it it was good to go. Any where in that area will be good.<br />
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I guess I will have to change the typo some day.....
 
Roadsmith cautions against filling until the oil runs out. Their spec is add 1 qt after draining.<img src="images/smilies/shrug.gif" border="0" alt="" title="Shrug" class="inlineimg" />
 
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<img src="images/misc/quote_icon.png" alt="Quote" /> Originally Posted by <strong>Matches</strong>
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<div class="message">Roadsmith cautions against filling until the oil runs out. Their spec is add 1 qt after draining.<img src="images/smilies/shrug.gif" border="0" alt="" title="Shrug" class="inlineimg" /></div>

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</div>ONE Quart are they nuts. i have 3 qts in mine and it still isn't all the way to the fill hole. It's about 3/4" below and thats where is going to stay. At one qt. theres not enough in the rear end to run down the axcel casing to lube the wheel bearings. unless your rear end is mounted upside down,then maybe one qt would work. Not sure about that.
 
Not sure if Roadsmith uses the same rear differential on all of their trikes, but did a quick search for "Roadsmith rear end" and it said that they use Dana 30 Spider gears in the housing. Then did a search for "Dana 30 rear differential fluid", which took me took a Jeep forum. Apparently on some Jeeps, it's a Dana 30 for the front differential, Dana 44 for the rear differential. I can only guess that Roadsmith is using a Jeep front differential (Dana 30)........anyways, in the discussion on the Jeep forum, it said that the fluid capacity for the D30 was 1-1.2 qts. and on the D44 it was 1.6 qts.

Heck, I'm still trying to figure out what Ford rear end is on this Lehman, LOL! All I'm sure of is that this one took 2.8 qts. and I've got no idea what little was in there to begin with. Sticking with the level plug here as well.

There was some mention on the Jeep forum about a filler plug on the differential housing cover.

Guess some aftermarket covers have the fill plug up higher, so one wants to only add the recommended amount for those so's not to overfill the Dana's.........

Spoke with an auto mechanic bud again about this Lehman and he said to bring it over to his place and he'll see if he can identify which Ford model the rear end is from. When I told him it took 2.8 qts., he said the owner was very lucky that the rear end hadn't blown out. Am also remembering when I first starting researching this stuff, one article said that these Ford rear ends are pretty substantial........."Built Ford Tough" applies in this case as it held up with a fluid capacity that was obviously way below spec.
 
They don't use the same rearend on all of their trikes. I was quoting what they rec. for the Ford. The Ford is used in the HT1800 and some others. The Dana is used in the VTX conversions. Roadsmith does not use a wet axle in the kit.

Shaft Driven Differentialford differential

Our differential is constructed from standard automotive ring and pinion gear sets. The original application of our differential was a Ford car. We cut down this brand new cast iron housing and make an Independent Suspension differential out of it. The components inside it are all brand new including the 2.93:1 ratio ring and pinion. We keep the speedometer correct with that ratio and tire diameter.
 
Ol' Grey,
I can't speak to what any of the other trike manufacturers use but the Suzuki C50 and C90 conversion by Lehman Trikes use a diff based on the Ford 6.75" design. We also run that diff upside-down from how it would have been installed in a car. The early units used the original cover which means that if you fill to the drain plug it is WAY over full. We call for 30 oz of 80-90 gear lube for that application.
 
They don't use the same rearend on all of their trikes. I was quoting what they rec. for the Ford. The Ford is used in the HT1800 and some others. The Dana is used in the VTX conversions. Roadsmith does not use a wet axle in the kit.

Shaft Driven Differentialford differential

Our differential is constructed from standard automotive ring and pinion gear sets. The original application of our differential was a Ford car. We cut down this brand new cast iron housing and make an Independent Suspension differential out of it. The components inside it are all brand new including the 2.93:1 ratio ring and pinion. We keep the speedometer correct with that ratio and tire diameter.

The more I read and research, the more I discover things that I don't know about :AGGHH:........My preference is wrenchin' on bikes and this is only the first (and probably last, LOL!) trike that I'm trying to maintain for a friend.

When you say that Roadsmith does not use a wet axle in the kit, does this mean that there's "wet" axles and "dry" axles ?

You quoted a fluid capacity spec of 1 qt. for the Ford differential used by Roadsmith. Does this mean that they've isolated the ring and pinion gears in the differential housing and that the 1 qt. stays contained in the housing ONLY ?
 
Ol' Grey,
I can't speak to what any of the other trike manufacturers use but the Suzuki C50 and C90 conversion by Lehman Trikes use a diff based on the Ford 6.75" design. We also run that diff upside-down from how it would have been installed in a car. The early units used the original cover which means that if you fill to the drain plug it is WAY over full. We call for 30 oz of 80-90 gear lube for that application.

Thanx very much for offering this, Lehman. Yes, I've pretty much figured out that the differential on this trike (2002 Suzuki VS800/Lehman) is from a Ford 6.75". There's a vent on the topside of the differential housing and the housing cover has no fill plug, only the 8 cover mounting bolts. The level plug (or at least what I'm thinking is the level plug and not an upside down drain plug) is situated on the inner, upper left side of the housing (opposite side from the cover side).

Am I correct in thinking that this differential has been installed right side up as it would have been in a car ? If it's been installed upside down, then the vent that is currently on "top", would have been venting DOWN in an auto application...........and, IF this differential is installed right side up, would the hypoid fluid capacity be more like 3 qts. rather than the 30 oz. that you've just mentioned ?
 
Ol' Grey,
The diff you are working with is most certainly one of the early ones. The plug you are referring to would have been the level/fill plug in an automobile application. The diff is installed upside-down and the vent was moved to accomodate the change in orientation. 30 oz of gear lube is all it should need.
 
Ol' Grey,
The diff you are working with is most certainly one of the early ones. The plug you are referring to would have been the level/fill plug in an automobile application. The diff is installed upside-down and the vent was moved to accomodate the change in orientation. 30 oz of gear lube is all it should need.

Thanx once again, Lehman, but ut-oh.....now it's overfull.......:gah:

Spoke with my auto mechanic bud and he concurred that if the differential had been installed upside down, either for more clearance or due to the need for the drive shaft to work in the proper direction, then yes, the fluid capacity would be much less as you've noted. Told me a quick way to check whether it was upside down or right side up was to look at the pumpkin. If the bulbous portion of the pumpkin was on top and the receiver for the drive shaft on a car was located near the bottom, then it was right side up. If it was opposite of that, then it would have been installed upside down. Will check that just to check it, but am assuming by what you've just said, I'll be draining a couple qts. of fluid out.

Hope that "steamer" is reading this in case his Motortrike rear end has also been installed upside down, which would mean that he also did an overfill, same as me. Will also PM him to give him a head's up.

Thanx again, Lehman and Ride Safe.........
 
Just eye-balled it and sure enough, it's been flipped, so will have to drain the excess.

Matches........Am guessing that Roadsmith also installs their Ford rear ends upside down as well, which means that you were correct on the 1 qt. capacity.

Just what I needed........more work! LOL! :woohoo:
 
Thanks Clay @ Lehman for watching and answering questions...It gets no better than coming straight from the manufacturer!
 
I'll second that, Bazooka.........won't deny that there's been some frustrating times trying to figure some of this stuff out, but Clay@Lehman came thru yesterday in a big way! :wtg:

Still have to drain this excess fluid from the differential. Ideally, I should remove the housing cover, let the fluid drain, then add the recommended amount. Two questions on this:

Is the housing cover gasket a Fel-Pro RDS13073 ?
Anyone know the torque spec for the 8 housing cover bolts ?

If I wanted to do a temporary drain this time until I can get the right gasket, would removing one of the lower cover bolts work as far as draining the excess ? Meaning, if a lower cover bolt was removed, would the fluid drain thru there or does the bolt go into a closed, threaded casing ?
 
Hope Clay doesn't mind me sharing this, he and his family have been involved in Lehman since 1993. Clay's dad Larry Strilchuk became John Lehman's partner and then Lehman Industries became Lehman Trikes in 1993. Larry went on to become president and CEO of Lehman Trikes. Clay had never mention this fact, but I now know that Clay KNOWS Lehman Trikes and we are fortunate to have his personal input here.
 

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