lackey454

Lost 5th gear again after less than 3000 miles. Mechanic said it was fixed for good. Looking to get different transmission. I have an early 1998 dodge truck with a 12 valve diesel engine. Do I have choices for replacement. Like a six speed that will slip right in?

patdaly

Depends, is it a 4X4 or a 2WD?

Slip right in isn't gonna happen, but it wouldn't be terrible to change it over to a newer G56.

lackey454

sorry I missed that 4 X 4 And the reference to G56 is just what I'm looking for. I am not very knowledgeable in the mechanical parts but I love this truck. Had it since it was made here in Fenton, Missouri. Got to see it being put together since I worked in the plant next store.

patdaly

What "fix" did your mechanic use?

I tried them all and until I did the captured nut, no luck.

Since I did that, not a niggle of a 5th gear problem.

NV4500 Transmission 5th Gear Repair

This explains it, there are cheaper places to buy it.

video showing it.

Been on mine for 80K miles now, zero issues and I lug mine at low RPM's more than anyone else I know.

Trust me, this is a far, far cheaper solution......

lackey454

Thank you for the help. He told me at the time that he was using something new that would not fail. I was in Utah when it did and had to drive all the way 1200 miles home in 4th gear. The synchronizers don't work right and at low speeds I can hear and feel the gears. I just want it fixed like new again so I can drive another 240000 miles. I can afford the new one. Original question. Do I have choices for replacement and which would you recommend

gorms

To fit a 6 speed in, either NV5600 (late 2nd gen early 3rd gen) or G56 (3rd and 4th gen) will need driveshaft modifications for length changes. Crossmember may need to be swapped or modified. Since your truck is already a manual you have most parts needed. Do some research on the 2, neither are cheap and both have pros and cons.

Personally I would get your NV4500 rebuilt, or get a rebuilt unit. The fix shown above works. Unless you tow very heavy regularly they hold up pretty good, as long as the proper fluid is used. Not regular gear oil!

patdaly

If you are dead set on a 6 speed, I would go with the G56 all the way. Parts support for the MN5600 is sketchy at best.

I agree with Gorms, get a quality rebuild on the 4500 from a place like standard trans.......