I've got a 1986 720, manual 2wd. transmission just went out, and I've got a friend of mine who can put a new one in for me, if I can just find the new one. so I'm calling junkyards and they're all asking me whether I have a 12 or 16 inch extension housing. and I have no idea. I've googled until I can't google anymore and cannot seem to figure it out. sorry for my ignorance, but if anyone could help me out I would realllly appreciate it. truck is located about an hour away so it's not like I can just grab a tape measurer and go outside. if it helps at all, the sticker on the door says it was manufactured 8/85 and has transmission fs5w71b.

i can measure mine... it seems that it would be the exact same as yours.... no idea before this that there was a difference

won't be home till later though...

I'd really appreciate it!!

no luck? google's been no help at all!!

turns out i can't get under the truck till saturday will post when i do though!

I appreciate the help, but I actually called a nissan dealership pretending to be interested in buying a tranny from them and they were able to look it up by the vin number...it's 16 inches, for future ref!!

well very nice! good to hear you figured it out!

I should have been on before today. The fs5w71b is the 5 forward version of the tranny that all the trucks came with. Its what mechanics call the long box. Cars with the Z or K engine came with the short box, which can take more power. The output shaft is the same but you need to have a longer propeller shaft.

I'm having the same problem replacing the trans in my 1985 720 4x4 and the shop it's at can't figure it out either...I am not able to get help so easy from Nissan dealers and junkyards are no help either...A friend of mine seems to be confident I need the 16" based on the fact it's a Z24 engine and 4 wheel drive, but I'm going to have to buy two transmissions if the first guess is wrong...Can anyone help???

flinterman2000 wrote:I should have been on before today. The fs5w71b is the 5 forward version of the tranny that all the trucks came with. Its what mechanics call the long box. Cars with the Z or K engine came with the short box, which can take more power. The output shaft is the same but you need to have a longer propeller shaft.

Any thoughts?...You seem to be well versed in the art of Nissan.

LOL!!!...engine says "Z24S" on the top cover FYI