Cannot decide on trans, been a while
 

Last time I posted was a ways back its been a long trip and still working on the 72 along with many other projects.


So I have a 04+ 8.1 (without egr) going with Howell engine dev for comp.

My 72 has been converted to a 1 ton dually for towing/toy not a DD, I have a nv4500 in the mint or can go the route of a 4L80e. Truck has a th400 in it currently so I am looking for input on best transmission for tow/toy between the 2.

I don't think I will leave stock however 500ish+ torque is good enough for me off idle. I have read Dirtylarrys post and he seems to be a wizard at these 8.1L so I hope he chimes in. Money is not problem between the 2 transmissions and what ever one I run with will have a gear vendors.

:chevy:

Re: Cannot decide on trans, been a while
 

4L80E, you won't need the GV unless you want more OD. The TH400 with a GV would be bomb-proof. :)

Gary

Re: Cannot decide on trans, been a while
 

I vote NV4500, but I like to shift it myself.
Really you can’t go wrong either way.

Re: Cannot decide on trans, been a while
 

Here is how I installed the NV4500 in my '72 Dually:

http://67-72chevytrucks.com/vboard/s...d.php?t=673588

A really easy & cheap way to get a heavy duty manual 5 speed overdrive in your truck. You just need to pay attention to what year and vehicle the trans and bell housing are out of.....

You won't need the GV unit with this trans. I can pretty much run any speed I want on the interstate with or without the trailer.

LockDoc

Re: Cannot decide on trans, been a while
 

I'm doing the GV for 3 reasons, 4 over for towing, double OD for when not towing. Already did the calculations for RPM and with the 8.1 with 4.11 it came out perfect.

3rd reason is just to have 9 forward gears total or 8 on the automatic ;)

If I go nv I need to figure out the best flywheel for 12 inch clutch that will work well on the 8.1 (internally balanced) and the pedals. I checked with southbend and they don't have a better input shaft for the 10 spline :( it's only for cummins.

Re: Cannot decide on trans, been a while
 

I doubt you'll need a larger input shaft with the 8.1L torque. I'm pushing over 600lb/ft through my stock NV4500 pulling over 10,000lbs with a 12" dual friction clutch. The NV's were rated for like 420ft/lbs or so but they really hold up well as long as a guy isn't hammering on it.

Re: Cannot decide on trans, been a while
 

Personally not the biggest fan of the NV4500 due to the 5th gear setup. That, and once you start pushing 800+ ft lbs of torque, 3rd gear can do a good job of shredding teeth. If you have an NV4500, I would use it, but if you have to buy a tranny, I would look into the Spicer 3053a. A fair bit stronger, much cheaper, and it will bolt to your engine if you source the right parts from a C60 or the like and allow you to run a bigger clutch.

Only downside is that O/D is only .85:1 vs the NV4500's .73:1, but that could actually be better with the Gear Vendors as then you would have 2 different overdrive ratios instead of two similar ones (i.e. more usable gears). Gear spacing is also wider (presuming you have a post '94 NV4500) which would be a plus so long as you have the Gear Vendors.

Re: Cannot decide on trans, been a while
 

Since you're tossin in the 496, have you considered an Allison? That's what they came with (if ordered with an auto).

Re: Cannot decide on trans, been a while
 

That's what I have behind my 2003 8.1. I also have a Workhorse 8.1 with the Allison 2350 MH six-speed automatic with lock up bolted to it, out of a motor home.

LockDoc

Re: Cannot decide on trans, been a while
 

Yea I don't want to cut out the floor and expand the truck body for it to fit, I have owned a Allison behind a 8.1 before it was very very strong however the parasitic loss was certainly noticeable between it and the 4l85e . I won't be towing anything large enough to warrant the Allison anyhow.

So looking at your thread there Doc.

https://www.advanceadapters.com/prod...llhousing-kit/

https://www.pricefalls.com/product/c...d=184105378733

still getting list together.

Re: Cannot decide on trans, been a while
 

I used the stock '72 bell housing and all of the stock clutch parts for my install. All that trick stuff is too rich for my blood....:)

LockDoc