I have an idea. (it might be a stupid one)

Website · Post by **tsmall07** » Wed Jan 02, 2008 5:42 pm

Billet Benny wrote:Yes, it will work.. And it has been done. Your particular idea is a little ghetto, but if u got it mounted well and all the vibes out of your d'lines and could get going from a stop it'd work fine. The tcase would survive no sweat.

There were a few guys back in the day that ran doublers with backwards 203's inbetween the tranny and tcase to make up for the deep gearing of portals.

If you did it it would remind everyone of that junky ranger leach had.

Thanks Benny.

bourban driver · Post by **bourban driver** » Thu Jan 03, 2008 9:10 am

Thanks for all the information on the 4L80!

Website · Post by **tsmall07** » Thu Jan 03, 2008 12:30 pm

I don't really understand how a transmission control unit would give me an overdrive in the trans...

Post by **Sandracer799** » Thu Jan 03, 2008 2:09 pm

tsmall07 wrote:I don't really understand how a transmission control unit would give me an overdrive in the trans...

He was saying one option would be to go with a 4L80E trans. A trans with an overdrive. And to operate said trans you would need a control unit.

Website · Post by **tsmall07** » Thu Jan 03, 2008 3:12 pm

o

I thought the link provided was just to a TCU. What about swapping in a 700r4? Is that trans as stout as the Turbo Hydromatic 400? Bowtie overdrives does make a pretty good OD unit for that trans.

I probably should have mentioned that I'm pretty happy with the way the truck performs stock. It meets my needs at the moment. This was really a mental exercise meant to come up with ideas if my needs change in the future.

bourban driver · Post by **bourban driver** » Thu Jan 03, 2008 4:15 pm

My 700R4 lasted about 300k miles, but the truck was relatively stock until the last build -- it only lasted about 120 miles after the build up...

I was asking about the 4L80 as a look into the future. The rumour is that the 4L80 is a TH 400 with an overdrive. Can anyone second that?

Post by **Sandracer799** » Fri Jan 04, 2008 6:56 am

bourban driver wrote:My 700R4 lasted about 300k miles, but the truck was relatively stock until the last build -- it only lasted about 120 miles after the build up...

I was asking about the 4L80 as a look into the future. The rumour is that the 4L80 is a TH 400 with an overdrive. Can anyone second that?

Yes the gearing is exactly the same except it has an overdirve.

As far as a 700R4 goes Tsmall, I have even heard of built ones from Bowtie overdirves failing. One down fall of the 700r (in my opinion) is the TV cable. If you do not get that adjusted properly you can burn up a freshly rebuilt transmission with in a matter of miles. That is one reason I wanted to get a 4L80E.

But if the truck is working fine for you right now, then I wouldnt mess with it.

What the saying, if it aint broke dont fix it

YouTube · Post by **TerryD** » Fri Jan 04, 2008 7:49 am

There are two options to help a 700R4 endure a miss adjusted TV cable. The first one is the Full Line Pressure kit which places full pressure on the valve body at all times, you still have to have the TV cable for shifting reasons, but it eliminates the line pressure control section of the TV valve. The second is a Full Manual Valve Body which turns the transmission into a manually shifted unit. It also maintains full line pressure.

I personally didn't use either in the one in my Camaro and (thanks to reading several books and talking to several transmission guys around) am able to adjust my TV cable without any problem. Just dont buy an aftermarket cable, buy one from GM. The 700R4 was behind the diesel's in that era in civilian trucks and the cable should be readily available. Also, the 700R4 for a diesel is slightly different from the ones for gas motored trucks and cars. Make sure you get the one for the diesel!