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Discussion Starter · #1 ·
I'm planning on buying a 4BT and keeping it stock (for now) this includes using the Chevy S-10 manual tranny for it, since right now I'm looking for the best fuel econemy(sp?) that I can get, how hard is it to "re-design" the gears in the tranny to better suit the Cummins 4BT? Is there a webpage that I can do this with or a formula that I can use if I have certain values? Hard hard is it to do so? (In case no one noticed, this is my 1st swap :lol: I have a mechanic friend that's going to be helping me, but I haven't been keeping in the best contact with him.

Pantherman
 

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That trans should be a t5 and should be used with caution it isn,t very strong
 

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Unless you use the entire gearset out of a donor trans I'd say it's pushing impossible to swap the gears! The cluster with individual gears must be an exact, as in perfect, match for the mainshaft. The synchros have to be in the right places, and all bearings, thrust washers, snap rings etc. must be in exactly the right place. The mainshaft is one piece so generally the only way to swap is to remove complete gearsets with matching mainshaft and cluster.

I too doubt the trans is actually strong enough, but a real light foot on take-off might let it live awhile. In order to match the tranny to the 4BT the best bet is to carefully figure your final drive ratios in the rear end, including what diameter tires you plan to use, and the power curve of the engine.

For the amount of work, money and backyard engineering involved in doing one of these diesel swaps it doesn't really pay to scrimp on a major component such as the trans. Unless it's an GM SM465 or better it's just not built to handle massive off-idle torque. That's the killer. Almost full power is applied at clutch release, unlike a V8 gasser that doesn't really make power until it's spun up a bit. SM465's are fine and work well, or even an old NP435 [granny-low truck 4 speed] might work okay.

Put in some overtime, get a second job or sell something and get a strong tranny ha haha!:)
 

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Discussion Starter · #4 · (Edited)
Put in some overtime, get a second job or sell something and get a strong tranny ha haha!:)
I am, unfortantly looking at that right now. I need more income to make this plan possible, as my current job cut back all of the emplyees hours from 10/day to the regular 8. And at my place, you made money in overtime. That was going to be another one of my questions as well, but seeing how you suggested the beefing up of the tranny, that allready answered my question (And yes, I have a tendency to be a lead foot so it is probally best that I upgrade the tranny).

The big reason I want to get this done is the cost of gas, here (In Ohio) it's $3.30-$3.40/gallon, and I can make biodiesel (Which I have tested in a Jetta) for between $0.70 and $1.00.


My mechanic friend constacted me a short time back, and it was the ring and pinion gears in the rear end he suggested changing for better fuel economy, rather than messing with the guts of the tranny.

Pantherman
 

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My mechanic friend constacted me a short time back, and it was the ring and pinion gears in the rear end he suggested changing for better fuel economy, rather than messing with the guts of the tranny.

Pantherman
If you have a 2WD you might want to check some of the local wrecking yards for a 2.75 rear axle assembly from a Monte Carlo, Olds F85, or Gran Prix from about 77 through 87. I believe the axles, bearings, drums, shoes and backing plates are interchangable. You would have to measure the WMS to WMS to first confirm this and if it fits you would have to change out the spring mounting pads. Good part is they can usually be had for a hundred dollar bill.
 

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Discussion Starter · #6 ·
I'll let him know that, he's out of town for the week (ISn't company training Fun?)

Pantherman
 

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Randys ring and pinion sells a 289 ring gear set for an S10 I believe! I've seen a 92 Ford ranger 3.9 cummins with the small 5 speed that is used behind a 4.0 It dino's at over 250 HP and only broke it once and many hard miles on it.
 

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why not just put a nv45oo in it instad of trying to beef the t5?
 

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I agree with BobS, that it's a whole lot easier to stuff another rear axle under there than swap out a R&P gearset. As long as the axle width keeps your wheels under the fenders, or close haha, you're good to go. Easy to cut off the old spring mounting pads and weld on new ones if needed, and available from JEGS, PAW or Slummit for cheap.

I knew I would be running close on my own conversion budget [so what's new?] and decided from the beginning to put the available money into good major components. Thank God I had Paul in NY willing to advise me on what to use [THANKS A BAZILLION AGAIN, PAUL!] for the swap. I ran out of dough near the end but all the main things were covered: good engine, strong trans [NV4500] upgraded front axle, steering, brakes, Dana 60HD rear. It runs great, drives fine, and later baby on the small stuff!

Yes, I have to stash pennies per month now for future improvements but so what: I've got a rig I love and CAN DEPEND ON because of good basic components.

JimmieD
 

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Jimmie, Your Welcome !
All went great and it was fun. I wish we were close so I could have been of more hands on help, 3000 miles make it difficult ha ha

Paul
 

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Yeah, is was a lot of fun, Paul, and you were my sanity in it most of the time. Just getting ready to start Phase II of tidying up details and doing more bodywork etc.
 
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