Is it really necessary

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Nov 10, 2019 | 09:33 AM

95fxstc

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From: Terre Haute In

Is it really necessary

FSM says loosen engine to frame and transmission to frame fasteners when removing primary chain case. Did the job several years ago and don’t remember doing that. So is it necessary. This is a evo softail

Nov 10, 2019 | 01:07 PM

joe40x

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Engine to transmission misalignment can cause the inner primary to crack. Is it needed if you're just taking off the inner? Probably not.
I have removed several without loosening the mounts with no ill effects. However, it's in the manual for a reason. Be on the safe side and follow the manual.

Nov 13, 2019 | 02:54 PM

95fxstc

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From: Terre Haute In

Quote:

Originally Posted by joe40x

Got it off noticed it was weeping a little oil where the transmission bolts to it. Do you know if there is supposed to be small gaskets around the bolt between the chain case and transmission or should I just use a small amount of silicone

Nov 13, 2019 | 03:15 PM

Dan89FLSTC

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Quote:

Originally Posted by 95fxstc

The mounting holes in the transmission case do not open into the inside of the case, so no oil is going to leak out through the bolt hole.

Looking through from the right side, you can see there are no bolt holes open into the left (far side) side of the transmission.

Last edited by Dan89FLSTC; Nov 13, 2019 at 03:22 PM.

Nov 13, 2019 | 06:42 PM

95fxstc

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From: Terre Haute In

Quote:

Originally Posted by Dan89FLSTC

the oil is leaking from the primary chain case not the transmission

Nov 13, 2019 | 08:11 PM

Dan89FLSTC

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No gaskets or seals are used on those bolts.

Nov 13, 2019 | 09:39 PM

monckywrench

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Quote:

Originally Posted by joe40x

Unlike rubbermount HDs where the gearbox is bolted to the engine, old style (including Softails) HDs with seat post between engine and trans have been known to move about because they are held by a rather springy structure, the frame. I loosen the gearbox (and engine if I didn't install it) and if you do both you will ensure they are properly torqued when you tighten them. Transmission bolts can work loose so I Loctite them which beats loose bolts damaging case threads... If any mount bolts are loose, remove and inspect the hardware. If loose in a casting, ensure the threads aren't damaged.
If replacing the inner primary cover absolutely loosen engine and transmission! Inner primarys are long, weak, easy to crack, and your replacement may not have identical machining and be towards high or low side of acceptable tolerances (or way out as I've seen with offshore parts).

Last edited by monckywrench; Nov 13, 2019 at 09:40 PM.