Is this a TH400 or 4L80??

[chev-obsession]

This trans is listed at an auction house about 30 miles away, I was hoping that you guys could help me identify it before driving over an hour round trip just to look at it closer. I would be buying it as a core, I’m leaning towards a TH400 based on the pan shape and some of the features on the side of the case, but the adapter is throwing me off.

Any ideas what trans this could be? Any info is greatly appreciated.

[GSP7]

look like turbo 4 hunert

Flip it over and look at the Pan

[b454rat]

TH400. 4L80 is easy to ID, has a waffle pattern on the bell housing.

[Accelo]

I agree it's a THM 400.
It has a governor, the squarish cover with 4 bolts.
No need for one on a 4l80E as the shifting is all electronic.
The transfer case adapter is likely worth more than the core.
Cheers.

[chev-obsession]

Originally Posted by Accelo

I agree it's a THM 400.
It has a governor, the squarish cover with 4 bolts.
No need for one on a 4l80E as the shifting is all electronic.
The transfer case adapter is likely worth more than the core.
Cheers.

Thank you. That’s what I was thinking… buy it for the adapter. I’m guessing it’s likely a 208 adapter? Doesn’t look like a 205

[Accelo]

Unlikely you will find the long foot 71-85 GM TH400 to NP205 adapter. Advanced Adapters has a reproduction that sells for $270.

Yours works fine. The difference between the usage is in the cross-member.

The short foot, that you have, typically have an asking price of around $400. Unsure if they actually sell many for that price or not?

[dieseldawg142]

yep, T400 with a 208 adapter.
i have a T400 with a 205 in my crew.

[57taskforce]

Definitely a 400. I’ve got some 400/round 205 combos laying around myself.

[57taskforce]

Originally Posted by chev-obsession

Thank you. That’s what I was thinking… buy it for the adapter. I’m guessing it’s likely a 208 adapter? Doesn’t look like a 205

You can tell it’s not a 205 adaptor because there’s no provisions for the 205 shifter bolt. Even up to the late 80’s the 205 adaptor is cast iron as well.

[chev-obsession]

Originally Posted by Accelo

Unlikely you will find the long foot 71-85 GM TH400 to NP205 adapter. Advanced Adapters has a reproduction that sells for $270.

Yours works fine. The difference between the usage is in the cross-member.

The short foot, that you have, typically have an asking price of around $400. Unsure if they actually sell many for that price or not?

Yes I am finding the 400/205 adapters are far and few between. Does that mean the adapter on this trans will work with a 205 (maybe with some modification)?

[chev-obsession]

Originally Posted by 57taskforce

You can tell it’s not a 205 adaptor because there’s no provisions for the 205 shifter bolt. Even up to the late 80’s the 205 adaptor is cast iron as well.

Thank you. I will continue my quest. I’m mostly trying to collect this type of stuff as I’m learning buy it when you see it vs try to find it when you need it

[57taskforce]

Originally Posted by chev-obsession

Thank you. I will continue my quest. I’m mostly trying to collect this type of stuff as I’m learning buy it when you see it vs try to find it when you need it

No problem. If you look at the picture I posted above, right behind the governor on the transmission you’ll see the hole in the adaptor where the shifter bolt goes.

[Accelo]

Did the 208 have passenger and driver side drops? If so is the adapter the same one?

[57taskforce]

Not real sure about the 208 adaptors honestly. I would think drop wouldn’t effect the adaptor but have no real experience there. I prefer the 205, 1st and the 241, 2nd In the solid axle stuff. All GM solid axle stuff is passenger drop. I’m not aware of any drivers drop 208’s but I’d have to say they probably would have had to come from a ford if there was. GM and Dodge were both passenger as far as I know. The 208’s were all 80’s stuff, for some reason it seems like ford was passenger drop by then but I could be wrong.

[chev-obsession]

So what’s the best way to hone in on a search for a 400/205? All of the 3/4 ton 4x4’s I come across seem to have a 203 or the undesired syncro 205.

[57taskforce]

K30 is a guarantee if it’s an original automatic truck. in automatic form they only came with the 400/205. After the early 80’s there wasn’t even an option for a 205 in anything but the K30 if I’m not mistaken. 85-91 K30 has the most desirable round pattern 205 case. (what I pictured above) The 85+ stuff does bring good money when it comes up for sale.

[chev-obsession]

Originally Posted by 57taskforce

K30 is a guarantee if it’s an original automatic truck. in automatic form they only came with the 400/205. After the early 80’s there wasn’t even an option for a 205 in anything but the K30 if I’m not mistaken. 85-91 K30 has the most desirable round pattern 205 case. (what I pictured above) The 85+ stuff does bring good money when it comes up for sale.

Thanks for the info, I will keep my eye out for them. I’ve only ever seen a handful of K30’s but you never know what will pop up.

[b454rat]

3/4 and 1 ton 1980 and older could have the 400/205. After that, then only 1 tons got the combo. The early 80s had the synchro, but can be converted over. OffRoadDesign.com has parts to rebuild 205s. Ford is driver drop for ever, Dodge was passenger like GM, up to 93 when the NBS style came out.

[Jeff's bowtie's]

I have one with a missing chunk and a broken bolt ear I was going use but found another one that I would sell $100.00 (shifter bolt not included)