Overland Journal: Discovery I, 5-speed

Antichrist

Expedition Leader
How are the 3.90 gears working out? How is the gear noise compared to the 3.54's? Was there a noticeable difference in driveability? I would like to lower my gear ratio a bit
You're actually increasing the ratio when you go from 3.54:1 to 3.9:1.
It does results in "lower" overall gearing, which is what I'm sure you're wanting.
 

jrose609

Explorer
You're actually increasing the ratio when you go from 3.54:1 to 3.9:1.
It does results in "lower" overall gearing, which is what I'm sure you're wanting.

Thanks for clearing that up for me. I had just gotten off work this morning after an 18 hour shift. Was dead tired.

I realize I mis-spoke. I do want to lower the gearing.......increase the ratio.

I was just wondering how Scott likes the 3.90 ratio............
 
Last edited:

JSQ

Adventurer
Thanks for clearing that up for me. I had just gotten off work this morning after an 18 hour shift. Was dead tired.

I realize I mis-spoke. I do want to lower the gearing.......increase the ratio.

I was just wondering how Scott likes the 3.90 ratio............

You don't have to buy a 1.4 t-case. You can just buy the high range gears and rebuild the case you have. There's only a 9 out of 10 chance it needs a reseal anyways.

I got a set from Rob Dassler.
Southwest Rovers LLC 505-872-7818

Should be somewhere around $4-500.
 

timmy!!!!!!!

Explorer
You don't have to buy a 1.4 t-case. You can just buy the high range gears and rebuild the case you have. There's only a 9 out of 10 chance it needs a reseal anyways.

I got a set from Rob Dassler.
Southwest Rovers LLC 505-872-7818

Should be somewhere around $4-500.

How hard was it to rebuild?
 

JSQ

Adventurer
How hard was it to rebuild?


I guess it's all relative.
I should think anyone posting in or reading this thread would either know how or be very interested in learning on their own be it hard or easy.

Then again some people call AAA when they get a flat tire.
 

timmy!!!!!!!

Explorer
I think I just don't have access to a shop to do that then. Otherwise I would try to get the gears and do it myself. I know I could drop a transfer case in a parking lot but taking apart the innards would be a different story.
 

revor

Explorer
How are the 3.90 gears working out? How is the gear noise compared to the 3.54's? Was there a noticeable difference in driveability? I would like to lower my gear ratio a bit, and I've been looking for a 1.4 t-case, but I think perhaps a white unicorn would be easier to locate in the US. So if not a 1.4, then I was thinking the 3.90 gears.

I'm of the opinion that you will benefit more by swapping the diff gears. While the 1.4 high range will give you the same (similar enough) final drive ratio as 4.1's in high range the final drive in low range is no lower. If you swap the gears and maintain the 1.2 high range the final drive in high is like the 1.4 but the low range final drive is much lower offering you much more control in the tricky stuff.
 

jrose609

Explorer
You don't have to buy a 1.4 t-case. You can just buy the high range gears and rebuild the case you have. There's only a 9 out of 10 chance it needs a reseal anyways.

I got a set from Rob Dassler.
Southwest Rovers LLC 505-872-7818

Should be somewhere around $4-500.
Thanks, Jack. I will get in touch with Rob. I wouldn't mind trying it myself.
 

Scott Brady

Founder
How are the 3.90 gears working out? How is the gear noise compared to the 3.54's? Was there a noticeable difference in driveability? I would like to lower my gear ratio a bit, and I've been looking for a 1.4 t-case, but I think perhaps a white unicorn would be easier to locate in the US. So if not a 1.4, then I was thinking the 3.90 gears.

I didn't have enough driving miles on it before leaving for Asia. Initial impressions were good as expected.

I am not sure I see the advantage of the 1.4 high range route. I would actually prefer to use a 1:1 high range case ratio (which I believe is available) and run 4:14 axle gearing. That gives an even lower low range ratio and still strong gears. Of course this is just conceptual as there may be some technical reason this is not a good idea. . .
 

jrose609

Explorer
I didn't have enough driving miles on it before leaving for Asia. Initial impressions were good as expected.

I am not sure I see the advantage of the 1.4 high range route. I would actually prefer to use a 1:1 high range case ratio (which I believe is available) and run 4:14 axle gearing. That gives an even lower low range ratio and still strong gears. Of course this is just conceptual as there may be some technical reason this is not a good idea. . .

Scott, I have a Tdi in my D1. Low range can be compared to an experience driving something manufactured by John Deere. The three hundy just chugs over the trails in low range.

My reason for the 1.4 is to "increase" the gear ratio in high range. I have 3.54 diffs. Most of the people I talk to recommend staying with the 3.54 diffs. The 3.54 gears are quiet, very strong, and cheap to replace. Stock diffs are a dime a dozen.

Seems it would be a lot less labor to install a 1.4 tcase. However, finding a 1.4 seems to be a different story.
 

R_Lefebvre

Expedition Leader
I didn't have enough driving miles on it before leaving for Asia. Initial impressions were good as expected.

I am not sure I see the advantage of the 1.4 high range route. I would actually prefer to use a 1:1 high range case ratio (which I believe is available) and run 4:14 axle gearing. That gives an even lower low range ratio and still strong gears. Of course this is just conceptual as there may be some technical reason this is not a good idea. . .

Funny you mention that, that's just what I was thinking to get a better crawl ratio, rather than the complexity of an underdrive unit.
 

Forum statistics

Threads
185,539
Messages
2,875,662
Members
224,922
Latest member
Randy Towles

Members online

Top