This ended up being a multi-stage question

I currently am driving a 99 sport, 3.9L 5 spd manual, 2wd.

Part 1: I have been looking unsuccessfully on how to tell what transmission I have. I have found 3 different answers thus far, and all seem to be "valid" but I don't know what applies to me.

Part 2which I can probably find on my own, but figure it worth asking if anyone can make it perfectly clear) What are my gear ratios?

Reason for asking: I want to upgrade to the 04 3.7L, 5spd man, 4wd, 4dr, but would like to know what my gas mileage will suffer to. (and how to tell the seller to find the same info I have already applied to my truck and my current mileage) thanks,

goat

 

Look in the glove box for a sticker. should have gear ratio's listed. For the transmission phone the dealer local to you and ask for a vin cross refrence.

 

I did check the sticker and from that, verified I have the 3.21 differential, also confirmed by the sticker on the rear axle, counted the bolts so know its the 8.25 transfer. But, I can't pin down my individual gear ratios in the transmission, as well as the tany itself. AX15, NV1500, NV3500 are the leading options I have found online thus far, but every place I look says something a lil different on what I "should" have. I was hoping there was a lil magic identifier, which might be talking to a (usually annoying, but knowledgable) dealship.

Thanks

 

there was a really long thread on here about manual transmission codes... the 4.7 (and 5.2 back before the 4.7) use/used the NV3500, do a search here on the forum, but i think you have the NV1500

 

I re-searched as many combinations and key words as I could think of, and could not find the thread mentioned, or am continuously skiping over it.

 

8.25 is the axle, not the transfer case. If you have a manual transmission you more than likely have the nv1500. you have long 3.21 gears because you have the 5 speed. ummm if you wanna know the gear ratios in the transmission just look up the nv1500 online, im sure you can find the gear ratios, they will all be the same, no different sets of gears or anything.

actually, here i found the trans gear ratios. the fact that its talking about a jeep liberty doesnt matter
http://en.wikibooks.org/wiki/Jeep_Liberty/Transmissions
its in the 2nd table from the top

 

i thought we pinned down that the 3.9's had the nv3500 after i forget when though

 

Wink, thanks for the correction, I apologize for my think-typing. I will try to separate them more difinitvely from the now. Actually, I have been to that site... and many others like it. Most say different things~ unfortunately.

Playmaker: Im glad to be as confused as everyone else on the issue. Truthfully, the AX15 has been the leading runner up to my first post.

What I would really like is a visual identifier that can't be questioned (like the 10 vs 12 bolt axle... you can do it quick and easy, and its a final answer), because I am getting the impression the answer may be dependant on individual trucks. This may be a plug location, housing mold pattern, anything?

 

easy way to figure it all out-

document the RPM and speed in 4th gear.

That gives you axle ratio.

Now do same for 1st, 2nd, 3rd, and 5th.

Now you can use the axle gear to deterime trans ratios. Then you can use the ratios to find out the tranny.



gear ratio= (rpm x tire diameter)/(mph x 336)

GR = (2200 * 29.5) / (60 * 336)

GR = 64900 / 20160

GR = 3.22

What makes that work, is that TYPICALLY the second-highest gear is direct drive- 1:1. So the number that's left, is the axle gear

3.22 * GR = (1700 * 29.5) / (70*336)

3.22 * GR = 50150 / 23520

3.22 * GR = 2.13

GR = 2.13/3.22

GR = 0.66 O/D


Note: all numbers fabricated from thin air.

 

he has a point, however, if you have put on bigger tires and not calibrated the speedo, or anythign like that, his idea won't work.