# Bellhousing Alignment How-To



## PontiacJim (Dec 29, 2012)

If you plan to upgrade or add a late model transmission such as the TKO, you want to make sure that the bellhousing has been lined up with the crank/pilot bushing. Not so much of an issue with the factory Muncie or Dearborn, or Saginaw, or T-10/Super T-10 BECAUSE these older transmission use a ball bearings which allow for a little off set if you have any.


The newer late model transmissions us taper bearings. Any misalignment between the bellhousing and crank will result in unwanted side loading of the input shaft which can destroy the taper bearings, create hard shifting, and even void the transmission warranty.

Found this old Car Craft magazine article that walks you through the steps to align the bell. Not too difficult and only needs the magnetic base/holder and dial indicator. You can get these cheap enough, even a Harbor Freight set-up should work.

RobbMc offers a nice set with different offsets once you know what you need. They lock into position once you have the bellhousing centered.



RobbMcPerformance Bellhousing Alignment Dowels


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## 67ventwindow (Mar 3, 2020)

Thanks Jim that will definitely help. I hope that deliveries will work for a early spring install.


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## armyadarkness (Dec 7, 2020)

Thanks Jim. I bookmarked it and will read it over a few times. Have been tossing and turning about this, so you saved me some leg work.


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## Noangelbuddy (Dec 6, 2017)

Jim,
I learned the need for this alignment when I bought my Tremec 6 speed. Had to buy an inexpensive magnetic dial indicator tool from HF, but the procedure was not difficult. I mated my Tremec to a Quick Time bellhousing (not cheap, around $900 if memory serves). I worried about possibly voidng my warranty and was diligent about following the alignment instructions (the instructions were not intuitive). In my case, no changes were necessary to the dowel pins; measurements were well within necessary tolerance. The factory located pins could not be improved upon. Maybe the more expensive bellhousing was worth the price after all?
NoAngel


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## PontiacJim (Dec 29, 2012)

Noangelbuddy said:


> Jim,
> I learned the need for this alignment when I bought my Tremec 6 speed. Had to buy an inexpensive magnetic dial indicator tool from HF, but the procedure was not difficult. I mated my Tremec to a Quick Time bellhousing (not cheap, around $900 if memory serves). I worried about possibly voidng my warranty and was diligent about following the alignment instructions (the instructions were not intuitive). In my case, no changes were necessary to the dowel pins; measurements were well within necessary tolerance. The factory located pins could not be improved upon. Maybe the more expensive bellhousing was worth the price after all?
> NoAngel


I don't know how far off any bell would be, I am sure most are just fine, but you probably get a few that are just a hair off. That hair off becomes a problem with these newer taper bearing transmissions and the damages or voiding the warranty.

When the TKO 500/600 was a fairly new offering, there were a number of complaints, and of course internet bashing. When I purchased mine, and I too was skeptical in throwing down $2,400 (at that time), I didn't want to have a trans that was not going to perform - I would have gone with a new aftermarket M22 as my other pick. I went to the Charlotte Auto Fair and they had a Tremec Booth/trailer set-up. I spoke with Bill Hanlon of Bill Hanlon Motorsports who was essentially the R&D man for the TKO transmission, racing a Mustang and learning what breaks, sending that info to Tremec, and then also modifying transmissions to hold up.

First thing was that the design of the synchro's was not like the earlier transmission. The guys who had high RPM engines found that the trans would not shift at higher RPM's. The synchro's as designed could not slow the gearing down fast enough to get a clean shift - so the stock out of the box trans basically had an RPM limit of 6,000 RPM's. HOWEVER, what they found a means to solve the problem which was to line the inside of the synchro with carbon fiber. Great right? Just add another $400.00 and you can have a high RPM shifting TKO. I don't see spinning my 455 that tight, so was not an issue for me.

The other thing was the bellhousing alignment which was critical because of the taper versus roller bearings of older transmissions. Misalignment worn the taper bearings out and also caused hard shifting issues. Most of just slap the trans in and go because that's how we did it. The only mention I was ever aware of with regards to bell alignment was when you went aftermarket and used a scatter shield or 2-piece bell for racing. How many of us used those on the street? No one I ever knew. LOL

Next was selection of the transfluid. Use the wrong type, one that is too "slippery" and again, the synchro's can't do their job and you are back to bad shifts. And you know some just assume what to use based on what they have always used on other late model transmission.

You have to "break-in" the new trans just like an engine for the first 500 miles. You can be driving it hard, doing burn-outs, and revving the heck out of it.

I was also told that you cannot shift a TKO like the "old Muncie's" that many of us were used to. The most common complaint was the missed shift from 2nd to 3rd and instead going right into 5th. He showed me how to correctly shift it by using your palm, pushing the shifter forward springs it over to the middle gate/center of the shift pattern and then go up into 3rd. If you grab that shifter like the old Hurst shifters and stab it into the next gear as we used to do, he said it will go into 5th each time - shift quadrants aren't so sloppy/wide like the old Muncie's. So a slightly different technique had to be used on the 2-3 shift.

I don't know if the carbon fiber lined synchro's are a standard item on the newer transmissions versus it was an additional option when I purchased mine.

So adding one of the *newer taper bearing type transmissions* has to begin with the bellhousing alignment. I would not do it for the traditional ball bearing types like the Muncie, Dearborn, T-10/ST-10 trans missions, etc..


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## Noangelbuddy (Dec 6, 2017)

Thanks Jim. I wasn’t aware that the Tremec needed breaking in. Not an issue for me since engine needs breaking in at the same time, but appreciate you pointing it out. Shifting a 6 speed will take some getting used to. Never missed a 2 to 3 speed shift with the original 4 speed; neither did my wife come to think of it. I expect that shifting a 6 speed will come with a learning curve. Thanks for the tip about using the palm, will keep it in mind.


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## PontiacJim (Dec 29, 2012)

Noangelbuddy said:


> Thanks Jim. I wasn’t aware that the Tremec needed breaking in. Not an issue for me since engine needs breaking in at the same time, but appreciate you pointing it out. Shifting a 6 speed will take some getting used to. Never missed a 2 to 3 speed shift with the original 4 speed; neither did my wife come to think of it. I expect that shifting a 6 speed will come with a learning curve. Thanks for the tip about using the palm, will keep it in mind.


The 1st minute of this video demonstrates how to do this. Now this is the 5-speed TKO, so am not sure on a 6-speed how that would work. 5 gears is enough for me. LOL


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## 67ventwindow (Mar 3, 2020)

I had a T56 before and loved it. The predominate experience prior to getting the T56 in 1995 was three on tree and that did not translate So I wasn't messing up as bad as when I went to a deuce and a half and its wacky shifting.

Do you remember what the tolerance was? I will probably just buy all three sets. Its a friends lift so I don't want to put him out waiting for a part.


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## armyadarkness (Dec 7, 2020)

PontiacJim said:


> I don't know how far off any bell would be, I am sure most are just fine, but you probably get a few that are just a hair off. That hair off becomes a problem with these newer taper bearing transmissions and the damages or voiding the warranty.
> 
> When the TKO 500/600 was a fairly new offering, there were a number of complaints, and of course internet bashing. When I purchased mine, and I too was skeptical in throwing down $2,400 (at that time), I didn't want to have a trans that was not going to perform - I would have gone with a new aftermarket M22 as my other pick. I went to the Charlotte Auto Fair and they had a Tremec Booth/trailer set-up. I spoke with Bill Hanlon of Bill Hanlon Motorsports who was essentially the R&D man for the TKO transmission, racing a Mustang and learning what breaks, sending that info to Tremec, and then also modifying transmissions to hold up.
> 
> ...


I hung out with the Hanlons a few weeks back. Their shop isnt too far from me and it's in an area that I cruise to. Super cool guys, very helpful and knowledgeable.


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## Noangelbuddy (Dec 6, 2017)

PontiacJim said:


> The 1st minute of this video demonstrates how to do this. Now this is the 5-speed TKO, so am not sure on a 6-speed how that would work. 5 gears is enough for me. LOL


Jim that video was most informative, thanks.


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## PontiacJim (Dec 29, 2012)

67ventwindow said:


> I had a T56 before and loved it. The predominate experience prior to getting the T56 in 1995 was three on tree and that did not translate So I wasn't messing up as bad as when I went to a deuce and a half and its wacky shifting.
> 
> Do you remember what the tolerance was? I will probably just buy all three sets. Its a friends lift so I don't want to put him out waiting for a part.


For TKO, .005"

Found another method:

The suggested points to measure opposite each other are 12 & 6 o'clock, and 3 & 9 o'clock. But I suspect if your high/low points were at 1 & 6 o'clock, then you would adjust for that IF they were out of spec.

Position the dial indicator at the 12 o’clock position, and zero the gauge. Then, rotate the engine slowly in the proper direction watching the gauge as the needle fluctuates. When you have found any high spots in the bell's circle, mark it on the back of the bellhousing with a marker, and record the amount.

This may require 2 or 3 full turns of the crank/dial indicator to verify the areas of misalignment. Once you have marked and recorded the measurement, bring the dial indicator to that high spot, then rotate the crank 180° across from it and verify the corresponding low point of the bellhousing. Mark this location and the measurement, as well.

After verifying the 2 points are 180 degrees apart, it’s time to get out the calculator. Subtract the lower number from the higher number then take the solution and divide it by 2. If your number is greater than .005”, you’re outside of the tolerance allowed by Tremec.

For instance, if your high point was .015” and your low point was .007” the difference would be .008” (.015-.007=.008).

When you divide .008” by 2, you get .004”. .004” is less than .005” so this example would fall within the tolerance.

If you use an offset dowel to correct any misalignment, make your adjustments, and repeat the procedure to check the bell alignment, and do so until you have the bell in alignment.


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## 67ventwindow (Mar 3, 2020)

PontiacJim said:


> For TKO, .005"
> 
> Found another method:
> 
> ...


 5 thousandths makes sense with the offset pins start at 7 thousandths. There is no making it tighter if its only 2-3 thou out. I will mock it up on the spare engine and see how it goes.


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## armyadarkness (Dec 7, 2020)

Im still moderately amazed that the center hole on the bell housing is consistent enough to take these measurements by. Especially looking for tolerances under 1/16. I would think that they'd want you to use the bolt holes (for the trans) in the bell housing


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## CoveKid19 (Nov 18, 2021)

Simple is how I taught my trainees when dialing in components in jet engines. Same method applies here. The simplest method (*two steps*) is to find the total indicated runout (TIR) while at the same time letting the dial indicator tell you which way, and how far the bellhousing needs to move to get the concentricity within tolerance.

1- *Find the exact point of the bellhousing's hole which is farthest from the crankshaft's centerline*.
Once the dial indicator (DI) is set-up correctly, rotate the engine and watch the DI needle until you see it moving in a counter-clockwise (CCW) direction. When the needle stops moving CCW, and just before it starts to move clockwise (CW) you've found that point. Now zero the DI needle.

2. *Find the direction and the distance the bellhousing needs to move.*
With the DI zeroed from step 1, rotate the engine and watch the DI needle (moving CW) until it stops, just before moving CCW. At this point the DI (plunger) is pointing in the direction the bellhousing needs to move while the needle is giving you the TIR. TIR divided by 2 is how far the bellhousing needs to move to make it concentric to the crankshaft centerline.


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