trans issue or lack of power...

T

Tom Scout

New member
73 Scout II, 727 rebuilt by sss 15k ago (not impressed), 3.31 gears, 33" tires, 304 from 69 1010 or 1110 I don't recall, motor has low miles, rpt manifold, 470cfm truck avenger, msd/pertronix ignitor, bored out and different cam installed, but I don't know the specs since the owner passed away. My issue: when I tried climbing a steep smooth rock, my Scout gets on the rock, then stops moving like I'm holding the brakes and stays at approx 1600rpm with the hammer down. My friend climbs it in a lifted cherokee, not fair. Is the torque converter is achieving lock up lower than what is appropriate for the new motor? That's while in 4 low. I'm installing 3.73's to help out, but was curious about the trans. Any info will be greatly appreciated, thanks everyone! I just want to beat his Jeep ;)
 
You can't compare the action of the Scout II with a Jeep. There is a significant weight difference with the Scout coming out on the downside of that deal!

3.31 gears certainly are not a gear ratio to be used in an offroad situation by any means, especially the type use you are referring to. And this is not a transmission issue as such unless it is being affected by some situation we don't know about.

The typical stall speed of an oem (and aftermarket replacement) torque converter is going to be between 1500 and 1800rpm. No way around that without having a converter built with a higher stall speed.

What you are doing is simply maxing out the performance potential of that vehicle as it's currently set up. For replacement gears I'd certainly look at 4.10 as a gear set that is much better offroad and still is perfectly capable of providing a good street-driven operation.
 
Thank you! 4.10.... Man, ill have to stop being a punk with 3.73 and go big. I appreciate your time, thanks again.
 
Are you able to achieve wide open throttle under less of a load? Were you experiencing any wheel spin during this climb? The heep prolly has locking diffs or at least limited slip. What about your diffs? Most likely open at both ends. I agree with mayben that your gears are pretty tall for the tire size and type of wheeling described.
 
Under less load, yes I can open it up more than enough. I have a trash lock in the rear and the Jeep is open front and rear. I bought 3.73 and Dana power loks to install front and rear in my spare 44's. I drive the Scout far to go camping, that's about the only reason I didn't go higher than 3.73, but if I don't like it, ill just get better at setting gears...
 
Sounds like the same thing mine is doing! Only I have 3.73 gears and 31” tires. It’s done it once when I was stuck in the snow and a couple times while trying to climb a rock, up hill. I don’t have a tach. So I don’t know what rpm it goes to but 1600 sounds about right. It just lugs the engine down but none of the tires turn. Do I also need lower gears? I hope you don’t mind me posting this here Tom Scout. Thanks!
 
I run 33's with a tf727 and the 3.73 gears. While I do have the 392 engine, I've never experienced the type of lugging described. It's not a gear problem. 3.73 is a respectable off road ratio. Its a tired ass engine problem most likely.
 
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