Best way to 4.10s, and posi in 35ttb

[00t444e]

Can you run a front 411 gear when you have a rear 4.10? That sounds like it would end up having more wear…. I’m trying to swap my 28 in my 89 ranger right now too, I have a fx4 rear end with 4.10s going in the rear, along with everything from the fx4 drivetrain I can use(engine, tranny, transfer case)

4.10 and 4.11 is the same thing.

 

[19Walt93]

4.10 and 4.11 is the same thing.

No they're not but they're close, I've seen 4 wheel drives with factory installed 4.10 with 4.09 or 4.11 in the other end. Stay out of 4x4 on pavement and you'll be fine. Lock it in 4x4 and drive on pavement and you'll soon find you're weakest driveline part.

 

[lowspeedpursuit]

I've read that front/rear ratio differences can be up to 1% on-road--possibly higher if used exclusively offroad--which covers 4.10 vs. 4.11. If given the choice, 4.10 is meant to be slightly stronger, because the tooth count is 41/10 (vs. 37/9 for 4.11). The extra tooth on the pinion means a bigger, stronger gear.


On finding gears, I started looking for D35 TTB 4.10s this past February. Placed a number of different orders, at steadily increasing prices, and watched every retailer refund me and flip their listing to "out-of-stock". Even people you would expect to have parts in-hand, like Ebay sellers, were just drop-shipping from Yukon. I would not be surprised if 9/10 listings at this point are misinventoried, rather than actually available.

Yukon told me they do plan to make more, but it could be "up to a year". Since then, the topic has come up and I've seen people say October and December, but at this point obviously both of those dates were wrong.
More recently, I saw don4331 point out that factory 4.10s were only available in '90-'92 Rangers/BIIs, which substantially limits the pool of used gears.

I would give up on finding 4.10s before Yukon resumes production, and either do the front axle swap or bump up to 4.56. Over the past year, Yukon's higher ratios have also slowly started showing out of stock, but allegedly Nitro still has 4.56 available*, and without insanity pricing to boot.

I was apprehensive about highway RPMs with 4.56, but it's actually been pretty manageable (although it was better before my rubber body mounts failed, and I had to switch to poly). I also appreciate the acceleration and especially the power driving on sand. That said, I do have the 2.3L. YMMV.
Maybe the biggest pain in the ass is that they literally don't make the right gear to correct the mechanical speedos for that much gearing.

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*EDIT: Nitro moved the page, and now shows 4.56/4.88, but no longer 5.13. Yukon shows out of stock for all D35 Reverse (TTB) gears. That's not to say no resellers have gearsets on the shelf (ECGS says they have exactly one 5.13), but like I said before, drop-shippers who haven't updated their listings are a lot more common.

 

[sgtsandman]

I agree with the RPM assessment. As long as you stick within the ranges of the gearing vs tires chart, the RPMs won’t be bad.

When I put a 4.10 axle in the 1998 with the factory 225/70R14 tires, I never felt the engine was over reving and that tire and gear match put the truck at the bottom or at least near the bottom of the acceptable range on the chart.

 

[Wannagodiving]

Im going from a stock 89 2.9 with a 7.5 ls w/3.73 gears to a 04 fx4 4.0(bored to 4.2, with a blower in the future) a fx4 manual tranny, transfer case, and rear end(with 4.10 gears) into a 1989 single cab. I really don’t need 4.56 gears… if anything I’d maybe drop down to 3.73 in the rear end. I’m only moving 30 inch tires, not planning to go bigger(well possibly up to 32, but not likely)

I've read that front/rear ratio differences can be up to 1% on-road--possibly higher if used exclusively offroad--which covers 4.10 vs. 4.11. If given the choice, 4.10 is meant to be slightly stronger, because the tooth count is 41/10 (vs. 37/9 for 4.11). The extra tooth on the pinion means a bigger, stronger gear.


On finding gears, I started looking for D35 TTB 4.10s this past February. Placed a number of different orders, at steadily increasing prices, and watched every retailer refund me and flip their listing to "out-of-stock". Even people you would expect to have parts in-hand, like Ebay sellers, were just drop-shipping from Yukon. I would not be surprised if 9/10 listings at this point are misinventoried, rather than actually available.

Yukon told me they do plan to make more, but it could be "up to a year". Since then, the topic has come up and I've seen people say October and December, but at this point obviously both of those dates were wrong.
More recently, I saw don4331 point out that factory 4.10s were only available in '90-'92 Rangers/BIIs, which substantially limits the pool of used gears.

I would give up on finding 4.10s before Yukon resumes production, and either do the front axle swap or bump up to 4.56. Over the past year, Yukon's higher ratios have also slowly started showing out of stock, but allegedly Nitro still has 4.56 available*, and without insanity pricing to boot.

I was apprehensive about highway RPMs with 4.56, but it's actually been pretty manageable (although it was better before my rubber body mounts failed, and I had to switch to poly). I also appreciate the acceleration and especially the power driving on sand. That said, I do have the 2.3L. YMMV.
Maybe the biggest pain in the ass is that they literally don't make the right gear to correct the mechanical speedos for that much gearing.

-----
*EDIT: Nitro moved the page, and now shows 4.56/4.88, but no longer 5.13. Yukon shows out of stock for all D35 Reverse (TTB) gears. That's not to say no resellers have gearsets on the shelf (ECGS says they have exactly one 5.13), but like I said before, drop-shippers who haven't updated their listings are a lot more common.

 

[lowspeedpursuit]

I thought the same thing and ended up being wrong, but again, old 2.3L vs bored 4.0L.

Generally, I try to observe the "meet or exceed stock RPMs" rule as a baseline, and fine-tune from there. My truck left the factory with 25"s and 3.73, so RPMs (in 4th at 65mph) were 3259. I installed 29" tires, dropping RPMs to 2809 and making 5th gear useless.
I needed deeper gears, and I couldn't get 4.10, so 4.56 was the only choice. They put me at 3434 RPMs--exceeding stock by 1 step on the chart--which ended up being fine.
But, other people's trucks can come with bigger tires and taller gears, changing their baseline, and all other things being equal, people with bigger engines probably wouldn't lose the ability to maintain speed in 5th like I did.

In any event, if you want 3.73s, those should be a lot easier to find in a donor D35 TTB. It's only 4.10s that occupy the sweet spot of being impossible to get both used and aftermarket.