Anybody a NV4500 trans guru?

wilamayb · Sep 2, 2012

Dad and I did a neat little conversion of a 95 model 5.9 cummins mated with a NV4500 trans installed into a 67 Ford F350. All was well until dad called to tell me that he had it stuck in overdrive. He pulled hard enough on the shifter to make the shifter jump the gates causing him to have to pull the shifter and remove the trans from OD with a prybar. He put it back in again thinking it was a fluke only to have it stick again. He did say it took a great deal of force to get it out with the prybar. I dont think it is the shifter causing the problem. I dont think it would be jumping the gates if the trans shifted with a normal amount of force.

Anyone know what could be causing this? I read on a diesel forum that it could be the detents in the synchronizer called "shift struts". Anyone have any thoughts?

Thanks!!

chevytaHOE5674 · Sep 2, 2012

Read up on modifications that should be done to the NV4500. It is common for the 5th gear nut to back off and cause major issues...

wilamayb · Sep 2, 2012

Yes, the 5th gear nut seems to be most of what I find. The syptom of that seems to be the lack of 5th gear. The gear is stil there on my trans. It pulls itself just fine in 5th. The problem is getting it out of gear once its in.

bison · Sep 3, 2012

(quoted from post at 21:22:44 09/02/12) Yes, the 5th gear nut seems to be most of what I find. The syptom of that seems to be the lack of 5th gear. The gear is stil there on my trans. It pulls itself just fine in 5th. The problem is getting it out of gear once its in.

ight be broke sinc ring, had that in bro's nv 4500,was stuck in third gear.
Loose 5th gear nut can cause it too.

Sprint 6 · Sep 3, 2012

I have seen other manual transmissions wear the synchros to the point the shift keys are overexposed when the shift collar engages the drive gear. The keys then pop up at an angle and lock the collar into the gear.

Jeff B. · Sep 3, 2012

I sell transmission parts for a living, and the nuts on the 5th gear are a real problem. There are various fixes for them, but the best one is to install an updated mainshaft with longer splines, and then use one of the locking nuts with little set screws to secure it to the mainshaft. I've even seen our shop go so far as to weld the nut to the mainshaft.
I would put up good money to bet that is your problem.

Dodgeit · Sep 3, 2012

(quoted from post at 15:05:33 09/03/12) I sell transmission parts for a living, and the nuts on the 5th gear are a real problem. There are various fixes for them, but the best one is to install an updated mainshaft with longer splines, and then use one of the locking nuts with little set screws to secure it to the mainshaft. I've even seen our shop go so far as to weld the nut to the mainshaft.
I would put up good money to bet that is your problem.

Try this site

http://forum.mopar1973man.com/forum.php?s=75bd490abcbee7f7d3b67047ef72dbfc

Anybody a NV4500 trans guru?

wilamayb

Well-known Member

chevytaHOE5674

Well-known Member

wilamayb

Well-known Member

bison

Well-known Member

Sprint 6

Well-known Member

Jeff B.

Member

Dodgeit

Member

Similar threads