Flywheel ring gear replacement

[buckmtn]

The ring gear on my flywheel has a couple bad spots with missing teeth. I was thinking the ring gear was bolted on into segments onto the flywheel. Just hoping I could maybe change it out by removing the inspection cover and swapping out segments or is this just wishful thinking and I have to pull the tranny. Manual tranny if that makes a difference.

 

[toomany]

You may be able to get the old one off without pulling the trans. But there is no way you will get the new one on without pulling the trans out....or altleast back far enough to get the flywheel off.

The ring gear is just that, one large gear that is a press fit onto the flywheel, sometimes there are a few tack welds.

To make installation easier. Place the flywheel in the freezer over night, you want to get it good and cold so is shrinks a little. Then place the ring gear in the oven and heat it up so is expands. You may want to clean any oil that might be on there off first before heating. Other wise you significant other might get pissed when you fill the oven/house with burning oil smoke. Take the flywheel out of the freezer and the gear out of the oven and assemble the two. I may just drop on, or you might have to tap it on. Let the temps stabilize and you should be good to go. However I would suggest putting a few tack welds on just to make sure it doesn't try to slip.

 

[Wrench]

Yep, I did the oven/freezer trick with mine after hours wasted trying to press or pound the stupid thing on. The inside diameter of the ring gear actually expanded by over a 1/4 inch, dropped right on with room to spare.

You'll have to pull the flywheel either way, might as well do it right off the bat and make the job easy. Get it surfaced while you're at it . . .

 

[4X4HIGH]

(1) Pull trans

(2) Remove flywheel

(3) Tap ring gear off

(4) Heat new ring gear with torch

(5) Grab ring gear with pliers and drop onto flywheel

(6) Install flywheel back onto engine

(7) Bolt trans back to engine

(8) Inspect old starter to make sure bendix gear is still good

(9) Start engine

 

[kitimatdude]

If it isnt too bad you can flip the ring gear over and reuse it. It might cause more wear on the starter tho.

 

[toomany]

If it isnt too bad you can flip the ring gear over and reuse it. It might cause more wear on the starter tho.

If you're going through all the trouble of pulling the flywheel and taking the gear off, might as well spend the $$ on a new gear. Plus the OP said his had missing teeth.

 

[bigchrisrogers]

Be very careful when removing the ring gear. You can usually just knock it off from the back bit by bit working your way around the ring. Be careful not to damage the cast iron flywheel which is not good at taking shock loads. Safest way is to drill a whole through the body of the ring gear, i.e. the area between the tooth gap and the inside diameter of the ring. This area is not hardened like the teeth. Then use a cold chisel to split the ring gear at the point where you've drilled the hole.

I concur the advice about chilling the flywheel and heating the ring gear. Best way is in an oven to get an even heat through the ring. You need to make sure you don't get it above about 250 degrees centigrade as this temperature will start to reduce the hardness of the ring gear teeth thereby significantly shortening their life. The worst way to heat the ring is likely to be with a torch because of the difficulty of getting an even heat and avoiding softening some of the ring gear teeth. You'll still get the ring on the flywheel O.K. with a torch but the effect of softening the teeth in one particular area will not be noticed from some months.

Some ring gears should only be fitted on one way. These have a chamfer on the end of each tooth to help the pinion slide into engagement. Make sure you fit them the correct way. Other rings have a larger chamfer on one side of the inside diameter. The large chamfer helps the ring slide onto the flywheel and sits better on the machined shoulder of the flywheel.

Most ring gears though can be fitted on either way.

When the ring is warmed place it on the flywheel, it should drop on fairly easily but may need tapping down during cooling. Make sure it is firmly against the shoulder. Use a feeler gauge of about 0.015" to check the gap between the ring and the shoulder, if you can get the feeler between the two in one area then tap the ring down with a copper headed hammer or an ordinary hammer with a soft metal block (Alumium, copper, brass, etc). You don't want to apply a hammer directly to the hardened teeth of the the ring gear. Typically the teeth are around 50 Rockwell hardness, but can still be damaged with a hammer.