Is it possible (modern transmission to older transfer case)

[Walts_restoration]

Has anyone ever done this? say mating up a 4l60e or similar modern overdrive transmission to a np205 tcase? maybe even a np208? The reason i ask is if i plan to use a 5.3/6.0 vortec, i figure i might as well use an overdrive transmission since i plan on running stock 3/4 or 1 ton axles, meaning ill have about a 3.73 or 4.11 gear, and im planning on having the truck be a highway trailer puller/daily driver. Any help or points in the right direction would be appreciated, thanks guys.

[Yukon Jack]

Give Advance Adapters a call, they have lots of adapters and can surely help you out.

[Russell]

32 spline NP208 or pass drop NP241 should bolt directly up to any 4l60e / 4l80e or either manual 5 speed manual available in the newer trucks without any adapters

[Walts_restoration]

Originally Posted by Russell

32 spline NP208 or pass drop NP241 should bolt directly up to any 4l60e / 4l80e or either manual 5 speed manual available in the newer trucks without any adapters

Well thats good to know, since this trucks going to be a driver the strength of the 205 isnt needed as much, since the 208 is like the 205 except a little lighter and not as strong case, as well as a lower gear ratio correct?

i like easy solutions to my ideas, gonna make funding it a heck of alot easier.

[FormerMember]

Originally Posted by Russell

32 spline NP208 or pass drop NP241 should bolt directly up to any 4l60e / 4l80e or either manual 5 speed manual available in the newer trucks without any adapters

Provided you get the correct NP241 or 208.

They come in 27 spline and 32 spline variants.

A 4L60E will be 27 spline and a 4L80E will be 32 spline.

You can mate a 4L60E to a 205 by cutting the output shaft of the trans or making a spacer and using a Th350/205 adapter.

[Walts_restoration]

Originally Posted by grendel

Provided you get the correct NP241 or 208.

They come in 27 spline and 32 spline variants.

A 4L60E will be 27 spline and a 4L80E will be 32 spline.

You can mate a 4L60E to a 205 by cutting the output shaft of the trans or making a spacer and using a Th350/205 adapter.

which trans would be better suited for a 3/4 ton truck used for towing? I assume the 4l80e would be a more heavy duty trans, am i right?

[FormerMember]

Originally Posted by Walts_restoration

which trans would be better suited for a 3/4 ton truck used for towing? I assume the 4l80e would be a more heavy duty trans, am i right?

4L80E is the more modern version of the Th400, which was used in the 3/4t and 1t trucks.

You could also bolt it to a late model NP205 with all stock GM parts.

[68Maniac]

Grendal, I am going to use the advance adapters 4L80e to 27 spline np 205 adapter. Were can I find info. on using a 4l80E to a late model 205 using all gm parts. Thanks

[FormerMember]

Originally Posted by 68Maniac

Grendal, I am going to use the advance adapters 4L80e to 27 spline np 205 adapter. Were can I find info. on using a 4l80E to a late model 205 using all gm parts. Thanks

That's spendy... at least stay 32 spline and keep the strength.

Use a round pattern 205 (86 and later, think) with the adapter and it bolts onto the 4L80E.

[68Maniac]

Yes....... I went into cardiac arrest when I saw the price. I'll see if I can round one up, here in a couple weeks I'll be at that point in the project. Thanks again!

[FormerMember]

Originally Posted by 68Maniac

Yes....... I went into cardiac arrest when I saw the price. I'll see if I can round one up, here in a couple weeks I'll be at that point in the project. Thanks again!

Can check with some of the vendors, too. ORD, NWF etc.

[morgans71]

It's been awhile since anybody has posted in this thread, but I was wandering if my late 80's model 205 off of a 400 turbo is a direct bolt on with the stock adapter to the 4L80?

['63GENIII]

I don't know if it's a "direct" bolt in but I think that's the one that guys are looking for. I think that TC makes the swap easier.