3800 3800 F-body Transmission Problems and (Hopefully) Solutions

[bs009]

Let me know if you want me to send that piece over. I can ship it tonight if you want to go that route. The one I have is 1/2" and I have a holley shim there too that could bring it out a little more too. Looks like you'd just need a gasket there between each piece too right?
Also a possibility of using a .75" RAM spacer to give you more flexibility and use less gaskets

 

[v6buicks]

Holy shit, that could be perfect!

I'm going to confirm that I can move the input shaft seal forward first. Then I'll PM you.

 

[v6buicks]

Hold up... This picture is all the proof I need. Shaft seal should be fine. Let's do this!

 

[v6buicks]

I was beginning to think that using modified stock T5 parts (We'll call it Idea #6) was going to be a very solid solution until I found this surprising difference. The stock T5 input shaft seal is a lot bigger than the one on the TKX.

bs009 is sending me some of his leftover spacers from his T56 conversion. I think they will be a better place to start.

 

[v6buicks]

The plot thickens.

Yes, that's my blood. The rest is in the process of being thinned out by cold brew. Next to it is a shim that I did not notice when I initially installed the Tilton retainer. Apparently I have to do some reading in the service manual to figure out the spec. I know there's a torque spec on the bolts, but a clearance spec too? Great.

This means that the DIY version of Idea #5 is a no-go. The spacer will need to be machined for this since it all sticks out of the case. Mr_Roboto's idea is starting to sound a little better to me now, but having machine work done to the spacer does not rule out Idea #5 completely.

 

[Mr_Roboto]

I lean towards leaving off the shelf parts off the shelf personally if plausible.

 

[v6buicks]

I lean towards leaving off the shelf parts off the shelf personally if plausible.

Wait. What? Lol

 

[Mr_Roboto]

Wait. What? Lol

Having/modding a spacer vs messing with the "snout" is preferable in my mind. I likee to have reversible mods.

 

[v6buicks]

Having/modding a spacer vs messing with the "snout" is preferable in my mind. I likee to have reversible mods.

Ahh. Yes. Agreed.

 

[Turbocharged400sbc]

Whatever your spacer/shim is you just need to use that shim with the same pocket Depth for that tkx bearing retainer. It probably has tapered roller bearings on the main shaft and that is for setting preload/end play.

So just machine the spacer with the tkx bearing bore depth and you can use that shim.

The spacer will also need a register where the Tilton goes on to keep it concentric.

 

[v6buicks]

Not that I wanted to spend this much money on a replacement part, but this would have been much easier. It's still short on the adjustment I need but fixing that would be as simple as making a collar/stop to go on before the threaded sleeve. Then a new stop pin of course. Oh well. It's on backorder anyway which are words that I no longer trust.

GM TKO/TKX CSC Slip-On Tilton T/O bearing - Modern Driveline

GM TKO CSC Slip-On Tilton T/O bearing High temp. mono-seal & a quad tensioner to ensure proper seal tension and the highest reliability

www.moderndriveline.com

 

[v6buicks]

I'll do myself one better. Tilton DOES make a universal sleeve which is good because the threads they chose are goofy as hell.

https://www.summitracing.com/parts/til-61-629

 

[v6buicks]

Well this crisis is just about handled already. No spacers needed. Thank god Tilton makes this sleeve. The extra threads offer much more adjustment. Why the Tilton retainer didn't offer more is something I still don't understand.

My machinist homie just had to bore out the ID of the sleeve to slip over the Tilton retainer. I have the bearing screwed on about 4 1/4 turns which puts it at the perfect height. Now I just need to figure out how I'm going to lock it into place.

 

[v6buicks]

I'm considering the idea of drilling/tapping the retainer bolts for a stand off. What do you all think?

 

[v6buicks]

While the 3/4" threaded standoff would have fit perfectly, I didn't feel right using it. They're all aluminum and not designed to have any sort of shear forces on it. I know that there will be barely any force being exerted on it in theory, but there's a lot of extra leverage on it too. I didn't want to risk anything stupid happening.

Instead, I threaded a couple standoffs of smaller OD, so that they would slip through the the bearing's locking hole. Then I threaded a long bolt through both standoffs. I didn't have one that was long enough to make it just two pieces. Oh well.

 

[Mattstrike]

If you have access to a machine shop, I would suggest tossing those spacers and make a single piece spacer from a large diameter steel round bar, center-drilled, large enough OD to have a nice big flat that fits the recessed boss in the retainer on one end, and turn the other end down to fit the smaller diameter of the slave mount hole. This would essentially isolate the bolt to only seeing some shear stress at the base of the joint and the clamp load, and the larger flat mating surface of the rod is the geometric constraint that takes the brunt of the bending moment. I don't have a ton of experience with fasteners, but generally speaking they are intended to act as a clamp load only.

I thought when people ran spacers they put them between the TOB and the clutch fins? Or is the concern that it would end up being rather heavy since the gap is that big?

 

[v6buicks]

If you have access to a machine shop, I would suggest tossing those spacers and make a single piece spacer from a large diameter steel round bar, center-drilled, large enough OD to have a nice big flat that fits the recessed boss in the retainer on one end, and turn the other end down to fit the smaller diameter of the slave mount hole. This would essentially isolate the bolt to only seeing some shear stress at the base of the joint and the clamp load, and the larger flat mating surface of the rod is the geometric constraint that takes the brunt of the bending moment. I don't have a ton of experience with fasteners, but generally speaking they are intended to act as a clamp load only.

I thought when people ran spacers they put them between the TOB and the clutch fins? Or is the concern that it would end up being rather heavy since the gap is that big?

I was kinda thinking of doing something like that, but the machine shop access I have is incredibly basic. I have a coworker do everything for me because I sure as hell don't know what I'm doing. I also have to squeeze in the work between actual work for the business which is already a lot to ask when we're busy.

I don't think it will be a problem though. There really shouldn't be much shear stress on the bolt. It's really only seeing was transmitted as bearing friction, right?

As for the TOB spacing, I don't think I've ever seen what you're asking about. Even adjustable bearings for forks are on a threaded sleeve. I did briefly look for a thicker bearing face though. I came up short. I needed to make up a solid 1/2" anyway.

 

[Mr_Roboto]

I was kinda thinking of doing something like that, but the machine shop access I have is incredibly basic. I have a coworker do everything for me because I sure as hell don't know what I'm doing. I also have to squeeze in the work between actual work for the business which is already a lot to ask when we're busy.

I don't think it will be a problem though. There really shouldn't be much shear stress on the bolt. It's really only seeing was transmitted as bearing friction, right?

As for the TOB spacing, I don't think I've ever seen what you're asking about. Even adjustable bearings for forks are on a threaded sleeve. I did briefly look for a thicker bearing face though. I came up short. I needed to make up a solid 1/2" anyway.

That is probably 15 mins with a not pos lathe and like 30 with mine if it were running.

 

[v6buicks]

I just don't see the value in it to be honest. The bolt should not be seeing much stress at all unless the bearing seizes in which case I'm going back in there anyway. Your idea is not out of the question though. Reasons for that will be just ahead.

First off, I'm going to use different bolts for this. 3800 flywheel bolts happen to be the exact same as the TKX retainer bolts except the head is bigger and flatter.

The trouble is that I can't just drill and tap the bolt like I thought. Here's the difference in width between the two bolts. Not much.

The length of the threads on my lock are the same as the height of the head. Not good. This means that drilling the bolt is likely to result in snapping the head off when it's torqued to the transmission.

To reduce the bearing leverage a little and maintain the integrity of the retainer bolt, I'm thinking about just welding a nut to the top.

 

[bs009]

A nut is a good idea, or weld on a stud too like the exhaust manifold bolts have.
What I would do is probably make a simple bracket that attaches to the bolts below and comes out to the HTOB with holes for the HTOB bolt to grab and keep it from rotating

 

[v6buicks]

Are you thinking like the part In red? Basically a washer with a threaded piece connected above the bolt. It would be pretty simple to make out of scrap sheet metal. While it would have some give to it, it would probably be less brittle.

 

[bs009]

Yeah but I would have it grab two of the deeper bolts to give it more strength.

Another idea, just get very long bolts for the plate on the trans and use nuts to secure that plate that's on the trans and then the bolt head and nut to hold down the HTOB

 

[v6buicks]

I have a better solution in the works right now. It will just be a longer, but much stronger bolt and and a union nut welded to the flywheel bolt. I'll get pics when it's done. If it doesn't work, I'll have 7 more flywheel bolts to play with and 4 tkx bolts. Lol

 

[v6buicks]

Here you go. More threads, bigger threads, and thicker shank. No spacers needed. With a little loctite, this thing will be planted.

I found that the unthreaded shank on a 1/4-20 bolt is the same thickness as the standoffs I was using before, so it will fit the bearing lock ring nicely. Upgrading to 1/4-20 also opens up my options for everything so I found a nice union nut and long bolt.

 

[Mr_Roboto]

That looks like a nice way to NOT have shit work loose, fracture or cause other problems. I think that's a good solution.