Hey guys,

My TH400 on my car worked perfectly until removal. No clutches slipped. Nothing like that. But as I dropped the oil pan, 2 screws snapped/sheared off. I've bodged them but I don't like it.

I have a second tranny, from a 1990 model. So it is the same BUT it has more miles and I don't know what condition it is in. I know it had like 2x the mileage as opposed to my 78k miles.

So, my thought was: Remove the inside from my tranny and put that into the good housing of the 1990 one. Also replace the tag to keep matching numbers...

I have heard that you need special tools to get the TH400 set up correctly, is that true?

Cheers

Damien

 

Well... if you couldnt remove / repair two snapped screws from an aluminum case you might not have the skills or knowledge necessary to re-body a complete transmission. Install the 90 TH400 and hope for the best. They were designed for big block in 6000Lb trucks so chances are it's just fine.

If the sealing surface was damaged it can cleaned and built up with alu welding rod and refinished, then new bolt holes can be drilled and tapped, offset if necessary.

 

Hi Daim

How about drilling the Broken Bolts through with a small drill and then using a screw extractor or if that doesn't work

Drill them out and then put new bolts in from inside the Tranny Casing, so the threads are hanging downwards and then put nuts on them

 

I'm sorry. It seems as if you could see the condition of the screws fitted to the pan. Can you tell me which two screws I unknowledgably snapped off? You seem to have been in my garage at the time...

I rebuilt my 5hp24 tranny in April. I am very sure I can get an old TH400 sorted. Thank you...

I was hoping for someone to have some experience with the TH400 but seems people question my intelligence instead.

 

OB, thanks for the idea, but I already did that. As the extractors didn't help to budge the screws, I srilled them out and that is why I am unsatisfied. The holes are too big. I already have fitted new gaskets and loads of RTV to seal it all but I just don't like it like that. Means more hassle getting for example the filter changed etc.

 

Nothing in life is perfect Daim

You could always use bigger bolts perhaps with a coarser thread and also some JB Weld or something like that

Get her back on the road Daim

It not like you'll be changing the filter every 5 minutes

 

No but I don't want to end up somewhere stranded with a leak because the RTV allowed ATF to get past...

 

Why not make the holes smaller again by welding them up and redoing the bolts/nuts/whatever it is?
What you're suggesting would be considerably more difficult but I suppose if you want to throw money and time at it, its your decision, I'm sure its all doable.

 

Both transmissions are not in the car. So there is no worry about that. And as I am doing a full restoration, I'm throwing money at it anyway

 

That makes it even easier to fix then, post a pic, it would be interesting to see whats/where

 

I've not done a TH400, but I have helped a friend do a Ford C6. I recall looking at the manual when my TH400 failed and I think you'll need some large snap ring compressors and spring compressors to get things apart.

In my experience they seem to last about 160,000 km and then need a rebuild. In mine the plates in the clutch pack with the scalloped edges broke up, so first and third clutch packs were engaged at the same time.

I'd pick up a rebuild kit and manual from Rock Auto and look at lots of youtube videos to see what tools are needed. You can probably add extra friction plates and steels to the clutchpacks to increase capacity, you'll just need a thinner steel backing plate to keep the overall clutch pack thickness the same. That's a fairly common upgrade for automatics.

Just be patient, take your time, and make sure everything is surgically clean and perfectly to specification in terms of thicknesses, clearances, etc.

 

Thanks for the tip, Jagboi! Just watched a teardown. It is easier than my 5hp24! That'll be a piece of cake. No eletronics and no electrical valves...

I'll probably overhaul the old tranny (function unknown) and use it instead...

 

You rebuilt a complex 5hp24 but have to ask about a simple TH400 on forum that's isn't known for it's deep dives into anything... especially transmissions. That doesn't pass the smell test.

 

Edited...

I was thinking of writing something insulting but thought that I'd prefer to leave you on your niveau below mine...

 

Good move, I'm from NYC, same place as Trump, you'd loose that battle.

 

If you drilled them out and now the holes are too big you could use Timeserts these are like helicoils but better.

 

STOP THE INSULTS, this is a friendly forum and lets keep it that way.

 

That's not an insult. It's a observation. An insult would have been to point out that using "Loads of RTV" on a transmission pan is the marque of a sketchy mechanic. I know, I know, it's just temporary for 2 years. We can keep going, we do this for fun here in the big apple.

 

I thought about that but one hole is oblong as I lacked a standing drill at the time.

Seems a straight forward job. Just checked, I already have the Jaguar repair manuals for the TH400 as well as the 4 speed from later models and the 4 speed manual. Would be a great chance to see if I can upgrade it a little. Some shift quality upgrades should be possible as well as a proper 1st lock up without the forced upshift...

 

Have you thought about repairing the hole with HTS2000 aluminium brazing rods, I used these to repair my flywheel cover the aluminium one that holds the engine speed sensor.