Drivetrain Bellhousing runout alignment

Sparky714 · Jan 1, 2022

I'm installing a Tremec TKX in my '89 foxbody. The instruction sheet that came with the transmission says you should check the center bellhousing to center crankshaft alignment wit a dial indicator. Maximum allowable runout is .005". I've never done this, so I found some youtube videos that explain how. So after doing the checks, my total runout is .0075". I'm .0025" out of their recommended specs. To get it into spec I'd have to get some offset dowel pins. So my question is, do you guys check this when doing transmission swaps or just bolt it up and send it? I'm using a new aluminum bellhousing. The old T5 bell won't work with the TKX. Car is mostly street driven, but does see some track use.

Monkeybutt2000 · Jan 1, 2022

You know what,I never did years ago and never had an issue along with several friends. I did do my last install and it was within specs. Are you sure you did it correctly?

Sparky714 · Jan 1, 2022

Monkeybutt2000 said:
You know what,I never did years ago and never had an issue along with several friends. I did do my last install and it was within specs. Are you sure you did it correctly?

Pretty sure I did. I watched several videos and the one from Silver Sport Transmissions is the one I followed. Pretty straight forward. Just trying to determine if .0025" out of spec is worth trying to remove the stock dowel pins and order and install offset pins.

Mustang5L5 · Jan 1, 2022

I did it the last time I installed my bell but don’t recall the numbers. I sent it, so I assume it was in spec. OEM bell

Is this a D9 bellhousing or an aftermarket unit?

Are your numbers repeatable?

Sparky714 · Jan 1, 2022

Mustang5L5 said:
I did it the last time I installed my bell but don’t recall the numbers. I sent it, so I assume it was in spec. OEM bell

Is this a D9 bellhousing or an aftermarket unit?

Are your numbers repeatable?

Yes, numbers are repeatable. Checked it a couple times with same results. I'm using this bell. https://lmr.com/item/LRS-6392A/79-95-Mustang-Tremec-Bellhousing

Mustang5L5 · Jan 1, 2022

Way I see it, you are at the point right now where doing it right isn’t much more work than what you are doing right now. It’s just a slight additional cost.

I’d prob double check a few more time and then run the offset dowels.

Not doing that step might be fine 9 times out of 10, but it’s a gamble you need to determine if you want to take.

Sparky714 · Jan 1, 2022

Mustang5L5 said:
Way I see it, you are at the point right now where doing it right isn’t much more work than what you are doing right. It’s just a slight additional cost.

I’d prob double check a few more time and then run the offset dowels.

Not doing that step might be fine 9 times out of 10, but it’s a gamble you need to determine if you want to take.

Agreed. Might as well spend a couple more dollars and get it to recommended spec while everything is torn apart. From a little searching, it looks like this place makes the easiest ones to install and they're only $35 a pair. Anybody have experience with them? http://www.robbmcperformance.com/products/dowels.html

limp · Jan 1, 2022

So your total was .0150 and you divided that number by 2 to come out .0075?

Sparky714 · Jan 1, 2022

limp said:
So your total was .0150 and you divided that number by 2 to come out .0075?

Correct

limp · Jan 1, 2022

Installing a TKX in my 83 and I just dialed in my bellhousing... I was lucky and my old SROD bell ( original to the car) was less than .002 with the stock dowels.. The offset dowels I saw offered were 007, 014 and 022...
My readings discussed how the older manual transmissions had the input running on ball bearings where the new tremecs are on roller bearings and they will not take the side loads that the ball bearing tranmissions will.
You have the hard part done, put in a set of .007 offsets and sleep better..... Your only decision now is which ones.... plain, slotted or cut for a open end wrench or the model that has the set screw in the middle to tighten the dowels so they never move...... Look around, the prices varied quite a bit... I believe the Summit brand were the least expensive........ Good luck

Sparky714 · Jan 1, 2022

limp said:
Installing a TKX in my 83 and I just dialed in my bellhousing... I was lucky and my old SROD bell ( original to the car) was less than .002 with the stock dowels.. The offset dowels I saw offered were 007, 014 and 022...
My readings discussed how the older manual transmissions had the input running on ball bearings where the new tremecs are on roller bearings and they will not take the side loads that the older ball bearings would.
You have the hard part done, put in a set of .007 offsets and sleep better..... Your only decision now is which ones.... plain, slotted or cut for a open end wrench or the model that has the set screw in the middle to tighten the dowels so they never move...... Look around, the prices varied quite a bit... I believe the Summit brand were the least expensive........ Good luck

Already got a set of these ordered. .007 offset should get me really close.

Drivetrain Bellhousing runout alignment

Sparky714

Monkeybutt2000

Mustang Master

Sparky714

Mustang5L5

That is…until I whipped out my Bissell

Sparky714

Mustang5L5

That is…until I whipped out my Bissell

Sparky714

limp

wrap a little cheese around it and its a done

Sparky714

limp

wrap a little cheese around it and its a done

Sparky714

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Drivetrain Bellhousing runout alignment

Mustang Master

That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

wrap a little cheese around it and its a done

wrap a little cheese around it and its a done

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