Last week I installed 4.9 gears into my truck.
I am so impressed with how the truck now drives. Much better power delivery.
Before the transmission would switch to 4th gear even at a slight incline. It no longer does that. Crawls better as well. Before I would get a transmission whine when going up steep rocks, thats gone as well. Takes off from the light with ease.
Here are some pics I took of the build. This isn't DIY, but if anyone has any questions Ill be happy to answer.
This is the donor truck. 2002 Montero Sport XLS 3.5L with non locking differential. Came from PicknPull in Fairfield, CA.
Removed the entire differential assembly.
This is the sticker to look out for to see what gears it has.
With some basic hand tools and wrenches me and a buddy were able to pull the thing in 40 min.
The rear we did a day before, I didn't take any pics then. It was easier than doing the front.
Factory rear ring and pinion
4.9 pinion gear installed
Replaced the old pinion seal with a new one. $11
4.9 ring gear on left, factory 4.27 on right.
Putting it back together. Cleaned all of the parts from oil build up.
New bearing over the factory locker air diaphragm.
A mechanic friend of mine helped with setting the gears right.
Here is the difference between the front diff in Montero sport (left) and factory (right)
I decided to install the complete Montero Sport diff without moving over any of the shifting mechanism and vacuum lines from the factory unit. I moved over the factory mounts and bolted it up to the truck.
Here is the 4.9 diff before I moved over the mounts.
Before installation I replaced the axle seals. $6 each.
Bolted it all back up, put fresh oil. Everything works real well. Now I have flashing lights when I go into 4wd. There is no sensor in front diff so thats something that Ill have to live with. It doesn't bother me much because it only flashes when Im in 4wd.
Here is a pic from past weekends outing.