That’s my thinking......
as long as I don’t get in “over my head.”
UZJ100 us spec transfer case re-gear... Has anyone done this? (2 Viewers)
- Thread starter NB100LC
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as long as I don’t get in “over my head.”
I’m barely following along...That’s my thinking......
Here’s the opposite question (I think): Could I re-gear my Tcase to reduce highway RPMs and increase MPG?
I have 33s w/4-speed, and my truck performs perfectly on the trails & beaches I frequent (often use 2nd start + 4Lo, engine braking in 4Lo/L is comically awesome), so I’m not looking to improve trail capability. Fast starts on-road aren’t that important either, just improving the economy of my 25-mile daily highway commute.
Well, in short yes, there is a higher hi range (4hi) gear set that can go in the transfer case replacing the current one. This would make all 4 transmission gears taller/higher. This would lower the rpms at a given speed and reduce the fuel consumption. The question is by how much or if there is some other inefficiency introduced that counter acts the gain in part.I’m barely following along...
Here’s the opposite question (I think): Could I re-gear my Tcase to reduce highway RPMs and increase MPG?
I have 33s w/4-speed, and my truck performs perfectly on the trails & beaches I frequent (often use 2nd start + 4Lo, engine braking in 4Lo/L is comically awesome), so I’m not looking to improve trail capability. Fast starts on-road aren’t that important either, just improving the economy of my 25-mile daily highway commute.
I’m looking for the opposite in a way, more crawl, more pep with bigger tires.
I’m barely following along...
Here’s the opposite question (I think): Could I re-gear my Tcase to reduce highway RPMs and increase MPG?
I have 33s w/4-speed, and my truck performs perfectly on the trails & beaches I frequent (often use 2nd start + 4Lo, engine braking in 4Lo/L is comically awesome), so I’m not looking to improve trail capability. Fast starts on-road aren’t that important either, just improving the economy of my 25-mile daily highway commute.
I would do a little more research before assuming that a taller hi gear will increase MPG. Some of the feedback I've read on the underdrive hi gear is that MPG actually improves because it keeps the trans in a better rev range and prevents hunting and unnecessary downshifting.
PabloCruise
SILVER Star
For climbing the passes, my 4-spd and 33s feels pretty doggy...
Yes, hills demand the down shift and I tow trailers on 60% of my trips.
@cmckThat’s my thinking......
It's been a year, did you install the under drive and how's it working for you?
It’s been installed since ~June 2019, it’s awesome. I have used the low range over 3 days of wheeling mostly blues on 35’s at Rausch Creek Offroad Park. We then took off for 3 weeks in Nova Scotia and NewFoundland and about 6000 miles where the underdrive proven on 33’s.
I have had zero issues after 8,000 miles and am very pleased with the rpm on the road. I love the low low speed crawl ratio, which provides control on obstacles, really great.
I’m pleased that my install has worked fine since it was my 1st thing like this. The very mechanical nature of the tcase helps this. Test fitting told me I needed more clearance in the case by not wanting to spin freely.
There is a low gear whine that is different than stock but I can easily overlook this.
Was that an easy install for a novice mechanic in their driveway? Any special tools needed? Also, who did you buy your gears from?
PabloCruise
SILVER Star
Good questions...
Was it easy? no. Was it hard? no. I broke a bolt, I didn’t clearance the case “enough” till final assembly, the bearing on the idler shaft had so little clearance I could not pull it, I just got another one.
Would I do it again? yes. What I did that made it easier (not cheaper) I bought a used case and regeared it, then switched it out. I used a friends lift and tranny jack to do the swap.
I got all the parts at cruiseroutfitters and they have like a list of what’s needed based on the year of the Tcase.
Tools covered here in this thread. Regearing to 4.88s
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@cmck Appreciate the follow up. Good feedback thats pushing me closer to pulling the trigger on this. I think I’d be inclined to drop the entire TC and do the job on the bench- but its gonna be a lump of iron to wrestle out (and back in).
Yes, on the bench is the way to do this. It’s not that hard to drop and lift it back in.
I looked at this Otramm video many times then dove in. This is only part 1 there are two. It is 80 series but the case part is really the same. It also helps to see the various gear pulls and sequence although it does not cover underdrive and there are some differences in between the 100 and the 80.
The underdrive uses an 80series idler tube/shaft which Kurt and cruiseroutfitters is stocking. Can’t say enough good about their support on this for me.
Bomar
SILVER Star
Did anyone do the part time conversion while in there?
Really leaning towards both sets of gears and part time
Really leaning towards both sets of gears and part time
Not I. I didn’t really consider it.
For those that have done the install themselves, how many banana's is this job?
I rate this as a
Or a I did it all myself with parts from cruiser outfitters (sumo brand gears).
I used a friends press, a friends lift and kept the rig running by buying a used case to modify. Then in the end did a swap. Had I not gotten a second tcase, I would have been very stressed, as it’s my daily.
If I did another one, I could do it in a single day.
Once I got all the parts and drilled out my broken case bolt it probably took 12-18 hours spread over weeks of various delays and scheduling.
I was a total newbie on Tcases and took my time not wanting to screw up. I had to make press spacer blocks and go get this or that puller to best take it apart.
