Manual Trans NV4500 and ZF S650 with 6.0L

[BMEP]

I'm researching manual transmissions to determine the options for a replacing the auto trans in a 2000+ Suburban.

Option 1: T-56
Option 2: NV4500 5 Spd. (Used in the 2500/3500 Silverado with a 6.0L)
Option 3: ZF S650? 6 Spd. Was this ever used behind a Gen 3, 6.0L engine?

I do some towing (23' travel trailer, 4500 lbs loaded) but may go bigger in the future. Otherwise, daily driving, commuting. Want performance and fuel economy.

Are there any modified 2000+ Suburbans out there with a manual trans?

How does the NV4500 shift comparred to the T-56? The ZF S650?

Thanks for the help.

[SteppinLo]

BMEP, I have limited knowledge but I will share.

In my opinion, the T-56 is a light duty trans and will not live under the loads your Burban can deliver.

The New Venture gear box and ZF gearbox are both HD units and will hold up well to what you are doing.

Now, keep in mind the all HD gearboxes have large internal parts and they WILL NOT shift like a sports car. If you force fast shifts, you will eat the synchronizers up quickly.

My owners manual for my HD says the 8.1 had a six speed option and the 6.0 was a five speed option. Does that matter? Not to me!

You might find the ratios for each and see what the spacing is. A close ratio box will be more pleasurable to drive and potientially give better economy. You will not have to rev the motor as hard with closer ratios.

I hope I have been of help.

Ronnie

[shakinlm7]

This (http://performancetrucks.net/forums/showthread.php?t=404105&highlight=nv4500) might help

[BMEP]

Thanks for the help. That was a great write-up on the Avalanche 6-speed swap.