a tremec case will not bolt to a stock t5 bellhousing without some work to make it to fit, the bolt patterns are different but the castings are pretty much the same and can be drilled for a tremec to bolt up. I think my old cast bell that came with my first tremec had a t5 casting number still on it. they used the same casting in some cases, just different finish work, think they grind the numbers off these days.

the bolt pattern and the opening are the only difference. 4.850” ID for a tremec vs 4.910” ID t5. the casting has the bosses for both bolt patterns but the t5 opening is .060 larger, aftermarket bells have shims to take up the difference.. Most just bought the tremec bell when it was cheap or got a junk yard srod bell which bolts right up vs drilling a stock t5 bell and trying to shim it if they even did that.

 

I have the same post on stangnet with some more pics of the different bellhousings:

https://www.stangnet.com/mustang-forums/threads/tr3550-with-a-t-5-bellhousing.905693/

So, if the T5 bell can be used - what's the cons to it? I know you said the center opening - what would happen with locating the trans itself or does it not matter because once it's bolted up it's not moving anyway? I would find it hard to think someone would take the time to shim it as you posted - they probably just drilled and tapped the 2 extra holes and on it went.

I guess my question now is what are the issues that one might expect by not using the proper bell - none? Is the difference in size negligible because once it's bolted up it can't move anyway? Are you really going to get driveline angle issues?

 

How in the world are you going to get the input shaft of the trans in the center of the cranshaft centerline if the trans can move around 0.060"?

 

cheaper to buy a junk yard srod bell then it would be to have a machine shop make a shim to try and use a one from a t5. But there are plenty of hacks out there who would just drill and tap it. The bell was less then $100 extra when I bought my first one in the late 90's and has the same casting number but is only machined for an srod/tremec to bolt up to it. Bosses for the t5 where never drilled and its 4.850 ID


If your worried that yours is a modified t5 bell check to see if yours is drilled for both a t5 and the tremec. Like I said I've seen the t5 casting number on bellhousings machined only for an srod/tremec before, I think I even still have mine somewhere in my pile of parts. I'll dig it out and take a pic if I remember when I have some free time. it is only drilled/ machined for the tremec bolt pattern. You might be able to check yours threw the fork opening without having to pull anything other then the dust cover using a small mirror and light. look for the two t5 bolt holes inside the bell on the drivers side. if its is drilled for both bolt patterns someone messed with it and you might want to pull the trans.

 

Jack Hidley - well the trans isn't moving around right? You are really locating/indexing the bellhousing on the motor and the trans is just bolting up to it. Remember this car is as I purchased it and seems to be running fine but I have no background on it as far as who or how it was put together - I thought it was strange to see a T5 bell on it since I've always thought you needed a different bell.

Perusing the forums it seems like people (and shops apparently) have been using T5 bells to attach 3550s on. I just want to know if there is anything I should look out for or any potential damage that might occur since I have no idea who put this together (shop, backyard, etc.). Did they shim the bellhousing, did they use offset dowels - I seriously doubt it but I could be wrong.

Plus we are talking about stock block with a stock bellhousing (not aftermarket or steel bell) and I would bet my money probably stock dowels so the indexing is right from the factory. So, wouldn't that in and of itself - given Ford tolerances index the bell already so that when you bolted the trans to the bellhousing it's centered for it already?

 

rednotch - good idea - I'll try and look and see. So you're saying that even though it has the E6 part number - it could be in fact a bellhousing for a 3550 because that is what they used to sell back then for them - modified T5 bells? Didn't know that.

 

index the bell would have nothing to do with it if the center is .060 wider... you would be guessing bolting it to the bellhousing every time. it would way out of tolerance, even if the run out was in spec and perfectly centered. The transmission locates off the center bore that's where you measure runout when you index a bell. now if its .060 larger indexing it isn't going to do any good if your using the bolts to center it and not the bore.


I'm saying they used the same casting for awhile, the didn't modified it.... it was not a t5 or tremec bellhousing until it was drilled and machined for one or the other.


here found one under ebay sold listings to show you "t5" part number yet only machined for a tremec or srod transmission..


added the inside pic to show its cast with bolt bosses for both transmissions

 

The bolts that hold the bell housing to the block, nor the bolts that hold the trans to the bell housing, do not center any of these items to each other. They can't.

The centering job is a function of the dowels at the block to bell housing interface and the OD of the bearing sleeve retainer on the face of the transmission. Without the base of the bearing sleeve fitting correctly into the hole in the bell housing, there is no way to know when the trans is centered behind the crank. With up to 0.060" of misalignment here, the input shaft bearing in the trans would be destroyed quickly, the car would not shift properly and other bad things would happen.

 

Well that clears it up for me alot - thanks to both of you!

I will look to make sure that it's the proper bellhousing that's on there - with the pic rednotch added, feeling much more confident that it's the right one but still need to make sure anyway or else the trans needs to come out.

 

Technically it would only be 0.030" of max misalignment from crankshaft centerline

Not that that makes it ok or any better.

That would be one hell of a machinist to makes a 0.030" thick shim with a 4.85x" ID. If I was tasked with this I'd probably modify the bearing retainer by welding on a larger shim and turning it down on a lathe. I think it could be done, but it's just waaaay less work to buy the correct bellhousing.

 

buy the ready made shims for the aftermarket bell then open the bellhousing bore to fit would be the easiest if you couldn't buy a bellhousing. But people " just bolted a tremec to a t5 bell" :wink2: