What does Index the bellhousing mean?

its getting the bellhousing/trans perfectly centerd. paul (killercanary) has a writeup i belive

http://www.mustangworks.com/articles/drivetrain/Bellhousing.html

That should answer all your questions.

Basically indexing a bell is a way to ensure that the centerline of the crank matches the centerline of the tranny. Tremec only allows .005" all the way out where the tranny goes into the bell which is NOT a lot way out there. This is IMPERATIVE to proper functioning of the tranny and not doing can and normally does result in a failure of the trans. MANY things can alter this, such as align boring (typically this moves the crank UP into the block, different bell housings, etc. Its not hard to do, and most mechanics and such done't know about it, but any reputable engine builder will. You can adjust the bell with either offset dowel pins or by re-machining the dowel pin holes but the later should be left to a professional engine builder. I used the offset dowel pins on my car. I ALWAYS suggest checking it, I was told by EVERYONE that I didn't need to and I had to replace the input bearing on my brand new TKO after 300 miles.

should you have to do this when putting in a t-5, wither in place of another t-5, or an aod-e, or does it only really mater when putting in a tranny such as the tko where things aren't simply bolt-up stock?

droptopford 5 0 said:

should you have to do this when putting in a t-5, wither in place of another t-5, or an aod-e, or does it only really mater when putting in a tranny such as the tko where things aren't simply bolt-up stock?

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From what i know, its just a tremec thing since the bellhousings are not exact. But like paul said a lot of other things can cause it to not be lined up.

I think what he mentioned in the first line was how tight the tolerances where on a tremec. I have only heard this being discussed concerning tremecs.


Hey Paul, what symptoms did your input shaft give you that you knew it had to be replaced? Was it a visual inspection?

I skipped over this step since i didnt have the tools to do it. But i had a vibration at 80+ so im going to check it now that the motor is back down.

You can get the dial indicators with the magnetic base you need to measure it with on ebay for less than $20.

Same problem.........vibration at 80+ with my tko.Didnt index my bell housing.I'm pulling my trans next week because of clutch problems so I'm gonna need to figure this out.

BDAWK2002 said:

Same problem.........vibration at 80+ with my tko.Didnt index my bell housing.I'm pulling my trans next week because of clutch problems so I'm gonna need to figure this out.

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Make sure you do a thread when the time comes or come back here. Here are my plans to try to eliminate this thing.

1.) Index the bell...make sure its good to go.

2.) Switch back to the exhaust hanger plate and modify the trans. Dont want to use a "home made" spacer...rather eliminate that variable and go with the stock pieces.

3.) I was thinking...my aluminum driveshaft came with a 10spline yoke i believe(?) anyway, i put the new one on there and could it be out of balance? Are there places that can balance a driveshaft? Or check to see if its in balance?


You got any ideas?

yes u can.
...hows ur flywheel look?

Nate, I know I forgot more than I remember when it came to dealing and diagnosing my trans problems. My symptons were: at approx 65mph it was like I threw a switch and the car would immediately start to vibrate. It'd vibrate so bad I couldn't see out of the mirrors. It also was hard to shift at high rpms, it was more noisey than a normal TKO should be (especially at the input shaft area, and the noise would diminish when I pushed the clutch pedal in), it generated a lot of heat, etc. I did everything including (in no particular order):

1. Replaced the ring and pinion
2. Replaced the differential, axle, and pinion bearings
2B. Replaced the actual differential, and axles
3. Replaced the U joints and had the DS balanced (which is actually not always a good thing... more on the later)
4. Re-balanced the tires
5. Had the car out at TTC's headquarters in Toledo ohio and had several engineers look over the car, they said the "cone" inside my DS was broken
6. Bought a NEW aluminum DS for a 96-up car (same yoke as a TKO) at Summit on the way home from TTC.
7. Put a piece of metal the same thickness as the stock exhaust hanger bracket in between the crossmember and the tranny
8. FINALLY re-indexed the bell housing using lakewoods offset dowel pins.

This all but cured the problem. It still vibrates a little but its not bad by any means either. The THREE biggest changes came from replacing the axle bearings, putting the spacer in between the tranny and the crossmember, and indexing the bell housing.
I've said it a hundred times since then, you MUST index the bell when putting these trannies in... you'd think that after all the money I spent and the time I fought with it that people would want to avoid the same mistakes I made and do it right. I almost sold the car due to this, I mean just add up what it cost me to narrow it all down with everything I did. hell, the drive to TTC's headquarters was a 7 hour drive one way!

Parts needed for a TKO swap in a 94-95:
1. TKO trans
2. bellhousing
3. 93-older clutch fork
4. shorter bell housing bolts for the top two holes
5. a fox dust cover for the bell if using the aluminum one
6. new clutch disc
7. driveshaft spacer
8. spacer the same thickness as the stock exhaust hanger bracket that needs to be cut to fit in between the tranny and the crossmember
9. New yoke for the DS
10. A dial indicator with a magnetic base TO INDEX THE BELL HOUSING
11. A tape measure (I did not do this but I wish I would have) to measure the "placement" of the tranny in the tranny tunnel. Measure from each side's pinch weld to the center of the output shaft of the STOCK trans, measure the distance from the center of the output shaft of the STOCK TRANS to the top of the tranny tunnel.
12. A flashlight to look up near the shifter area to ensure there is no contact between the tranny and the tranny tunnel
13. GM SYNCHROMESH tranny fluid
14. this "may" be for fox's only... but when using a STEEL bell housing you will want to check the area between the crossmember and the back of the bell as it typically hits if the crossmember is not modified and moved back.

That

Looks like I'm gonna be indexing the bellhousing next week.I wasnt aware of the spacer between the crossmember and the trans either I'm cleaning out my garage right now so by next week at this time I should be well into the job if not complete.I'll reply to this thread and let everyone know how it works out.Dose anyone know the correct way to put in a driveshaft when both the driveshaft and tranny are new?Dose it just bolt up or am supposed to line up the paint marks with something???

Take killer's advise. I even had to index my mcleud as it had .011 runout. And the indexing sticker on the bell had the numbers at .01 and .005. They were wrong.

killercanary, why would replacing the ujoints/getting the DS balanced not always a good thing? just curious.

BDAWK2002 said:

Looks like I'm gonna be indexing the bellhousing next week.I wasnt aware of the spacer between the crossmember and the trans either I'm cleaning out my garage right now so by next week at this time I should be well into the job if not complete.I'll reply to this thread and let everyone know how it works out.Dose anyone know the correct way to put in a driveshaft when both the driveshaft and tranny are new?Dose it just bolt up or am supposed to line up the paint marks with something???

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I dont know about installing a new driveshaft. But the spacer is to make up for the lack of the exhaust bracket that is there with the stock t-5. You can use it though if u grind off a part of the Tremec that is only there so the same tranny can be used in the gm f-bodys im pretty sure. They had a very good thread going about it on the corral.

OK the car is in the garage & I'm gonna start taking it apart tommorow.Anyone have an idea where I can buy a dial indicator to index the bellhousing.

If you need it quickly, harbor freight or Sears. Otherwise I would go with the Summit one. Harbor freight has cool digital ones though.

BDAWK2002 said:

OK the car is in the garage & I'm gonna start taking it apart tommorow.Anyone have an idea where I can buy a dial indicator to index the bellhousing.

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Hmmm lets see....i think this was said above in the thread.....lets see if i can find it. Ah HA!

nmcgrawj said:

You can get the dial indicators with the magnetic base you need to measure it with on ebay for less than $20.

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Otherwise i found them to be pretty expensive. You need the magnetic base to stick on the flywheel.