TH400 differences?

So im getting ready to rebuild my th400 thats going in the sedan and ive got a few questions.

Bought the B&M Transkit, and it said not to be used with transmissions newer than 87. But now i look at the summit site and it doesnt have that disclaimer anymore and the applications go up to 90 now.

Got my trans and noticed trans mount bolts are metric, so now im thinking i may have a newer trans. Was told it came out of an older diesel mini bus, but could it be b/c its canadian built?

So what are the differences between the 64-87 and 87-? th400?

John

 

On the 87 and up 400's the cases took 7 check balls instead of 6. The case, plate, and valve body gaskets are different. I don't remember for sure if the valve body itself is different. I hope somebody can add to this.

 

I'm not too certain about internal differences, but I do have one question for you.
What engine are you using? There's a few different bellhousing patterns for that tranny. If it did come from a deisel, it will have the BOP pattern. That won't bolt up to to a Chevrolet engine if that;s what you're using.

 

Are you sure? I have r&r'ed a few chevy trucks that had the 6.2 and 6.5 diesels that had 400's with the chevy bolt pattern. Monstergarage87 says it was out of a mini bus some I would think it has a 6.2 or 6.5 diesel.

 

I already had it mocked up in the car and it bolts up to the motor just fine.

But now what i dont understand is why one kit will fit up to '90 and another will only fit up to '87? Do they just have the extra check balls and an extra set of gaskets?

 

If my memory serves me correctly there's also a difference in the output shaft between passenger and trucks.

 

should be an aluminum tag riveted to the side of the trans that will tell you what year it is, just look at it the two digit number would be the year.

 

Tried to read it, but its caked up with who knows what. Tried cleaning the tag but still no luck.

 

Should have the year and code letters stamped, so you should be able to wire brush it and read the numbers, but go easy since it is aluminum

 

Ok, cleaned off the tag today and it says:

84 FM 79025

So if anyone cold decode it, that would be great.

John

 

I believe your tranny is an 84 model. You should be fine with your shift kit.

 

yeah, it would be from 1984

 

A son of a guy I used to work wiht had an '83/84 Chevy truck that was originally a 6.2, when that swapped to a 350 gas engine, the trans pattern was BOP, not standard Chevy. I do know that the 6.2 was originally derived from the Olds V8, I suppose it is possible that the later blocks were made witha Chevy pattern maybe?

 

Schweet! Thanks....

Now ill tear it down and polish the case.. oh-ah . But first i gotta fix the damage from the 'mishap' . Seems it easier to pick up a trans than it is to set it down.

John

 

I think you're confused? the 5.7 diesel was the olds engine, with a BOP pattern. The 6.2 was a chevy, with a chevy bolt pattern. I've swapped out both.

 

I was always told the 6.2 was derived from the 5.7, and the blocks were the same. Perhaps the info I was given was wrong.
Sorry for any cornfusion.