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View Full Version : 6 speed manual behind a 6.5?



Railroad Ron
02-28-2010, 21:18
Anyone have any experience and/or thoughts on putting a late model 6 speed from a GM pickup behind a 6.5? My NV4500 is about toast and I thought maybe I'd upgrade.

Robyn
03-01-2010, 07:22
As long as the input shaft configuration (spline count and size and the pilot brg journal are the same) you should be set.

Make sure the front pilot on the tranny where it fits into the bellhousing is the same too/bolt pattern.

Overall length (4x4 applicaton??? ) can effect driveline lengths.

Not familiar with the 6 speeds particulars.

Overall as long as you can get it in there the idea of 6 gears is great.

Just check out the mentioned items and if it will fit, go for it.

The likely most common tranny behind a 6.5 was the 4L80E auto and the sticks were sort of scarce.

Have fun and keep us posted.


Robyn

joed
03-01-2010, 08:13
I looked into this briefly last year - I was contemplating converting my 6.5 K3500 auto.

From what I recall:

Bellhousing wise, it should bolt right up, but would require a custom clutch for the 6.5. Southbend clutches thought they could produce one.

If you have a 4wd, you'll have to use a different transfer case - one from the newer HD trucks (dmax or 8.1) as the ZF-6 output shaft is different and won't work with the older t. case. I suspect the overall length would be different, requiring driveshaft mods.

With the added cost of getting a transfer case, I decided it was cost prohibitive for me.

Hope this helps.

Joe.

THEFERMANATOR
03-01-2010, 22:17
For the transfer case you can buy the 29 spline input shaft for the 261/263 series transfer case and drop it into the 241 transfer case if this is a 2500. If it's the 3500 with the oddball case then yes you would be better off finding a 261 transfer case from an ALLISON/ZF6 truck.

Railroad Ron
03-20-2010, 16:39
Fermanator, what all was involved in dropping the Duramax/Allison into the 'burb? I'm almost thinking that dropping a complete Duramax/6 speed(or Allison)/T case into the pickup might be the best bet.

THEFERMANATOR
03-22-2010, 09:39
Fermanator, what all was involved in dropping the Duramax/Allison into the 'burb? I'm almost thinking that dropping a complete Duramax/6 speed(or Allison)/T case into the pickup might be the best bet.

Check out the diesel conversions section here, I have it posted.