New here. I'm looking to see if anyone might be able to steer me in the right direction.
I've got a 85 Pickup originally a 5 Speed gaser, but the last owner swapped to the 2LT turbo diesel. I love the truck.
After driving the truck for a year, I have come to dislike one thing about the truck, and that is the gearing. It has gear code G292 which is 4.10's and at about 60-65 I'm looking for 6th gear. I hate how it feels like the motor is just screaming going down the highway. So I'm thinking I want to try to track down a set of 3.07's (G662) Its got 33's on it now and I can't go higher without a lift and I'm not really looking to do that. I do a fair about of highway driving with it. I know it has the power to go to 3.07's because I can cruise at 35-40 around town and I'm always in 5th. Also doing 65 on the highway I can pass someone going up hill without downshifting, and the diesels are supposed to be slugs, in that respect.

I know it is probably going to cost me more to get the 4.10's swapped out than I am going to save on fuel, but I would enjoy listening to the low end torque going down the highway, and I feel like I might increase the lifetime of the vehicle.

Does anyone know what the 4x4 2LT's originally came with?
Does anyone think this is worth my time/money? Am I crazy?

 

what rpm are you at when going 65?

 

4WD 2L-Ts had 4.10 gears. There are no 4WD or 2WD 8" axles with gears higher than 3.90 AFAIK.

I don't know about how crazy you are. But I don't see how you can be thinking that a 2L-T has so much power. It only makes 84HP @ 4000 rpm and 137 ft.lbs. @ 2400 rpm. Whereas a 22R-E makes 116HP @ 4800 rpm and 140 ft.lbs @ 2800 rpm, and a 22R makes 103HP @ 4800 rpm and 133 ft.lbs. @ 2800 rpm. Meaning, it's not even as powerful as the engine that was in there to begin with. Though it might make 4 ft.lbs. more torque than a 22R, it makes 19 less HP.

EDIT: I guess you're right, there's some 2WD G662 axles(8" 3.07 gears).

I just used a gear calculator to figure out how much difference going from 4.10 to 3.07 gearing would make. Running 3.07 gears with 33" tires would be ~ the same as keeping the 4.10 gears and running 44" tires. With 33" tires, 3.07s, in 4th gear, at 2000 rpm you'd be going 63.98 MPH. With 44" tires, 4.10s, in 4th gear, @ 2000 rpm you'd be going 63.88 MPH.

So, basically, you're saying you think you've got enough power with a 2L-T(that only makes 84HP & 137 ft.lbs. of torque) to run 44" tires with 4.10 gears. Really? You think so huh?

Yeah...I doubt it...

FYI...
65 MPH w/33" tires in 5th gear(.85:1) and 4.10 gears equates to ~2306 rpm.

 

As for RPMS I don't have a tach. If there was an easy aftermarket one I could install I would.

Ok so maybe the problem isn't my diffs but actually my tranny. Does anyone know the difference in 5th of the 5 speed gasser tranny vs. 5th on the diesel tranny. Are there any markings on the tranny I can look to see if it is from the truck or the engine?

Just seems odd to me that I can be going uphill at 35mph in 5th and not have the engine rattling or shaking. Seems like plenty of power for me, but i guess that could be because my last vehicle was a VW Caddy with a 1.6 Natural... you want to talk about a sick goat...

EDIT:
I've also got a set of 31"s on Alloys that I could throw on if need be.

 

My problem is just the opposite. The RV conversion built by my son has 33" tires. This gives the rig with the original 2L-T enigne legs that are too long. The original tires were 225/75R15. I did not find a place where the differential ratios were listed but it gets scared of hiils about a mile away with these big tires. Maybe 31 inch tires would give it better legs. Works great off road though.

 

I was just driving my girlfriends Jeep liberty with the VM 2.8L. Granted that motor produces 50% more torque, but it also weighs a lot more. But I was driving it and the tach sits at about 1500rpm when its on the highway and on flat ground with good fuel I got up to 33mpg.

My Toyota just sounds too high doing 75 down the highways. If I could borrow a set of 44" tires [and they could fit] I would throw them on my truck and give it a try.