Your driveshaft will have to be shortened.

 

So can I not just use a 4L80 driveshaft?

 

You can just shorten the Yoke no drive shaft modification necessary.

 

Ok, as far as the wiring goes, I understand I have to swap a few wires around in the main connector and add an additional VSS plug, but are they simply using the same harness from the 4L60 and making those modifications to it or is it the other way around where they are using the different trans harness for the 80 and modifying it to work with the current system?

 

I'm 99.9% positive that they are using the factory 60 harness and repinning it.

 

Just swap the white and brown wire in the 20 pin connector.. Add wires for the ISS, TH400 Long yoke and trim it off 5/8" and put it on the stock DS. Very easy.
need Dipstick tube also.

 

I have the stock single pc shaft with a yoke I got from jake's performance. The trans was a very small amount longer but the yoke was a bit shorter and they work as if I spec'd it out that way, I have a reg cab long box so this info may not apply. I used a conversion joint at the yoke. If you have a 2 pc shaft it may be a whole different story.

 

2pc DS works just fine.. just need a Yoke..
I used a TH400 long yoke and trimmed it just alil. Been kicking for several years now and has been 150+.

 

Does the trimming the yoke deal only work on 2wd? I am going to have to do something with mine this winter when I do the swap. Currently I have a Driveshaft Specialist alum shaft. Obviously I don't need a th400 shaft, I just hate to have to send my driveshaft back to have it shortened.

 

Well I guess I got screwed over on this 4L80E I got....guy said it was out it an '01, but after further research it can't be because it's missing that bolt hole at the top center of the bell housing. What should I do, use it or just re-sell it and cut my potential losses?