Front Differential Seal Hemorrhaging

[Mavigogun]

Cheep things are expensive. Such as this 2008 C50 Tramp. That said, it appeared to be low mileage; where it was stored featured dust accumulation with no signs of leaks under the cycle, and the differential case did not show signs of leaking. Changed the motor oil, drove it home 550 miles- and the front of the differential case and, slightly forward, a brake cable are covered in what seems to be oil.

So, now I get to learn all about rebuilding a differential.

Along the way, I left the parking brake on a couple times. Could this have taxed the differential to seal failure? The trike seemed fine while I was riding- do you reckon that means the gears in the differential are still intact?

I’ve read that Lehman attributes some differential failure to certain batches of faulty components- is there any way to identify if this differential includes those parts?

Thanks for your consideration.

[Gorilla]

Cheep things are expensive. Such as this 2008 C50 Tramp. That said, it appeared to be low mileage; where it was stored featured dust accumulation with no signs of leaks under the cycle, and the differential case did not show signs of leaking. Changed the motor oil, drove it home 550 miles- and the front of the differential case and, slightly forward, a brake cable are covered in what seems to be oil.

So, now I get to learn all about rebuilding a differential.

Along the way, I left the parking brake on a couple times. Could this have taxed the differential to seal failure? The trike seemed fine while I was riding- do you reckon that means the gears in the differential are still intact?

I’ve read that Lehman attributes some differential failure to certain batches of faulty components- is there any way to identify if this differential includes those parts?

Thanks for your consideration.

Seal could of just dried out due to lack of use. I would just change the seal and see what happens. Good luck

[Mick]

I would check the oil level in the differential and top it off and see if it comes back. It could be dry from lack of use,but make sure it has enough oil in it. If its a pinion seal and you want to change it,youre going to have to take the rear end apart to do it.

https://atpautomotive.com/re-seal

Some years ago mine started leaking from an issue thats too long to write here and I used ATP to stop it. I had it in there a good 8 years before I took it and had it repaired.

If Lehman had an issue with the differentials unless you could find an experienced installer to talk to ,youll never find out. When they were open I found them to be a very closed book about issues with their trikes and my installer was my only source of help. Lehman had a nasty habit of building the trikes and then expecting the dealers to fix what they didnt do right at the factory and make up the difference. My trike was built in Spearfish and I had it at 3 different dealers before I found one that would fix it right.

And sadly my installer passed a couple of years ago from cancer. I call him my installer because he basically took off the kit and put it back together correctly. When my trike was built Lehman was building the TriGlides. The going joke was the best of the best were building the HDs and the best of the rest built all the others.

[Mavigogun]

So, I wriggled underneath the differential and scraped a thick coating off of the underfairing, then differential, then soaped up the differential casing, front and back, just to have a clean start for whatever came next. Next was removing the fill plug to look for obvious damage, see just how dry the inside of the casing was; I removed the plug, then carefully inserted a cotton swab, head bent over to measure 3/4”- the level below the plug I understand our late guru was adamant we not fill beyond. Over half an inch came back saturated with relatively clean looking oil. No tell-tales of metal particles.

I have only a few clues as to what may be going on here. I believe the previous owner rode the cycle very, very few miles; I reckon they, or the Harley dealership they traded for it at, overfilled the differential. Would that be enough for excessive pressure to push the gear oil past the pinion seal? If not that, I have no idea what coated the differential and underside of the fairing in dusty oil. I rode the cycle a couple blocks to get it’s inspection permit, then ‘round my ‘hood for 10 or 15 minutes- probably never shifting over 3rd gear. Parked in the garage, I inspected for signs of leakage around the pinion, found none.

I’m not sure what to do. I’ve got more oil in the case than I’m told is healthy. I had signs of a leak- well, oily, caked on residue around the pinion. Maybe I should ride it harder, check again? Or should I siphon out some gear oil first, until the cold level is 3/5” below the plug?

[Mick]

I was always told for measuring the oil was to stick your pinky finger in and the very tip should just touch the oil in a Lehman differential by 2 different installers. Youve got it all cleaned off now just check for leaks. You could be right on your diagnosis. Unless somewhere underneath you have an engine oil leak with a trail.

[Sidecarbill]

Differentials don't have pressure, unless the vent is clogged, then they can build pressure and leak. Check the vent.

[Mavigogun]

Check the vent.

This may sound dim, but, where is the vent? The plug appears to just be a simple plug. Is it possible there is no vent? I could install a vent plug- either simple, or with a line.

[Sidecarbill]

Well if it's a car axle it should be on top of one of the axle tubes going to the rear wheel. Most cars are on the left side.

[Jack Klarich]

Look @ this google link, your differential needs a vent, here are examples of many of them

Make sure the vent is not plugged up, if it has a hose connected try to blow thru it

https://www.google.com/search?rlz=1C...h=543&dpr=1.63

[rhino 2]

This may sound dim, but, where is the vent? The plug appears to just be a simple plug. Is it possible there is no vent? I could install a vent plug- either simple, or with a line.

The vent should be high up on the differential...It has to be higher than the drain plug...It looks like a cap....And if you tap on it with your finger [Lightly] it should spring a little up and down.. IF it doesn't it might be gummed up and not venting..

[Mick]

My Lehman has the vent on the upper part of the differential with a plastic drain hose running out of it. If you can get a small mirror and check out the upper part of the differential to see if maybe they took the hose off of it. I know mines a Monarch II but maybe the differentials are similar.

https://www.trikezone.com/suzuki-trikes.php

I dealt with these people for some parts years ago. Theyre still selling Suzukis maybe they could give you some help with your trike also.

[CrystalPistol]

It's vented. It is a Ford 6.75" ring gear diameter integral rear axle (Pinto, Mustang II, etc) cut down and uses new shorter axles. Vent being plugged will cause pressure to build in the housing as you ride as gear lube expands as it heats up, if not vented seals are the next avenue of escape.

Our Mustang leaked after drives, but not just sitting parked. Vent was not open. I opened it, ran hose up into frame opening above the axle, no more leakage when driven.