Engine/Transmission (1994 - 1998) New 98 12V Engine/5 Speed Questions

[Cummins12V98]

My Son now has my 98 12V in my sig.

I just bought a 98 12V 5 speed 2 wd with 313K to run around in and commute to jobs I am helping my Son with.

Seems to be more rough on shut down than the other 98.

Idles and when increasing the RPM's runs a bit rough then smooths out. Just ran a tank thru it mostly 60-70 mph freeway and hand calc got 22.6 mpg.

Do all Dana 80's have limited slip and require slip lock?

How do you drain the trans fluid I did not see a drain plug. Do you fill to the bottom of a fill hole?

The guy said he had Dynomite Diesel add a "economy" fuel plate. Still has Cat but no muffler.

Has a South Bend Clutch seems good. The guy said it was the "second up from the bottom" what one would that be?

With a light load the clutch or something else makes noise until the RPM is above around 1,600. Kind of a rattly vibrating metal sound.

Thanks in advance.

 

[Flinty]

No, all Dana 80s do not have a limited slip diff; there should be a sticker on the underside of the hood or in the glove box indicating gear ratio and whether or not it is an open diff. In the absence of a sticker you will have to pull the cover and see for yourself.

Trans oil is drained by pulling the lowest bolt on one of the side covers for the PTO. Refill to the bottom of the inspection plug on the side.

I can't tell you which clutch you have. I have heard about their clutches making noise and for it to be normal, call Southbend.

Luck,

Jon

 

[Cummins12V98]

No, all Dana 80s do not have a limited slip diff; there should be a sticker on the underside of the hood or in the glove box indicating gear ratio and whether or not it is an open diff. In the absence of a sticker you will have to pull the cover and see for yourself.

Trans oil is drained by pulling the lowest bolt on one of the side covers for the PTO. Refill to the bottom of the drain plug.

I can't tell you which clutch you have. I have heard about their clutches making noise and for it to be normal, call Southbend.

Luck,

Jon

Thanks for the info!

Anyone else have some answers?

 

[Bob4x4]

Some gear rattle can be considered normal.The clutch model would depend on when it was installed SB has changed their line up since the old days.It used to be a con o.Now I think it may be a larger od and a 6 speed style hub

 

[Bob4x4]

With the last 8 of the vin it is easy to find out ls or not

 

[Cummins12V98]

The rear axle is an open diff.

I am thinking the factory 3:54's were changed to 4:10's.

I am turning about 2,130 RPM at 70. How does this compare to anyone else's 5 speed?

 

[The patriot]

@ that RPM I'd say theyre 3.55's depending on tire size. If theyre stock or close to, it's 3.55's.

 

[JR]

I believe you have 4:10s. I have 3:54s and with the stock tires (waaay back) and my 47RE I was running around 1800rpm @70mph IIRC.

The final gear ratios between the NV4500 and the 47RE are pretty similar, with the NV being at around .75:1 and the 47RE being at .69:1 (close enough )

 

[hsmith]

3:54s here in 5th is around 2100 @ 70 or so.

 

[Too Tall]

I believe you have 4:10s. I have 3:54s and with the stock tires (waaay back) and my 47RE I was running around 1800rpm @70mph IIRC.

The final gear ratios between the NV4500 and the 47RE are pretty similar, with the NV being at around .75:1 and the 47RE being at .69:1 (close enough )

This is what I remember on my 95 with the 5 speed. Around 1700 - 1800 at 70 mph with 3.53.

 

[Big Red 94Ram]

I'm at 1950rpm @70 mph with 3.55s. 245x75rx16 tires. 94 5sp

 

[Cummins12V98]

Looks like we have some varying opinions. I am leaning towards it having 4:10's.

 

[SnoKing]

You could always jack it up, mark the drive line, mark the tires and get two helpers to turn the tires one revolution while you count the drive line revolutions. 4:10 will be just over 4 turns and 3.54 will be 3 and a half turns.

Bored nothing to do, buy an old Dodge RAM to play with!!!

SNOKING

 

[Cummins12V98]

Since it's an open diff it would be easy to do that. You want to be on the ground?

Since I will probably be trading my 11 in later this year I figured I would keep the value up as much as possible. I actually miss tinkering so I bought this new to me 98 to save money on fuel and it's fun to drive. I have not had a stick since my 81 VW Diesel pickup.

I don't have much info on the truck since the Grandson sold it to me because the owners moved to Hawaii to retire. I was told that Dynomite Diesel installed a "economy" fuel plate. It's pretty basic until 1/2 throttle and then it pulls pretty good up to 3K when it de fuels. May slide the plate forward to see how it responds. Really just interested in dependable 21-23mpg economy.

 

[SnoKing]

Pretty busy right now. Getting ready to go to Desert Aire for the long weekend. Going Wednesday to stay over night at Lake Conner Park and then head out Thursday for Eastern Wash. We had the Travel Supreme trailer delivered. Lot has lots of room. 2 30A RV and 1 50A RV outlet. Still trying to work the bugs out of the new transmission and TC unlocking. John L. sold me a PCM, but have not installed it yet. Reworked all the grounds, APPS rewired and new Alt.

We could do it early June.

SNOKING

 

[Cummins12V98]

I was just kidding about you being on the ground....what do you think I have a wife for?????

Desert Aire I assume is in Eastern WA? My folks have a lot in Desert Aire but it is in Indio, CA.

 

[Joseph Donnelly]

Drain the NV4500 by removing the bottom PTO bolt from either side. Fill to the bottom of the pipe threaded fill plug.

 

[Cummins12V98]

Thanks Joe!