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Transmission for 4BT?

10K views 25 replies 5 participants last post by  Tshootz 
#1 ·
So I am interested in replacing the motor in my 1996 Blazer with a 4BT Cummins because I've had so many problems with the motor in it. My Blazer has the New Venture Gear 3500 manual transmission and the New Process 233 transfer case. I was just wondering if anybody knew if that transmission and transfer case would be able to hold up to a 4BT or if I should look into getting new ones? And if the transmission will hold up where can I find an adapter for it?
 
#2 ·
Those seem a smidge light for the 4BT.

The flywheel housing (the part the transmission bel housing bolts to) is replaceable on these, with different patterns to choose from.

Do you have a 4BT already?

I suspect not (I hope I'm wrong though ;) ).

There is a whole lot of information that will help in the stickys, both the "Cummins Tech" sticky and the "transmissions and adapters" sticky all graciously provided by our very own Bob S. :) (TY Bob)
 
#3 ·
I do not have one yet. I have it running okay right now, but I decided that if I have anymore problems with it I am just going to replace it. And the 4BT seams like a well diversed option that I could do a multitude of different things with. My Blazer has the push putton transfer case and I would really like to keep that ability, so what would you recomend for a transmission and transfer case?
 
#4 ·
I don't know a whole lot about the push button part of that system (controls, actuators, if a computer is involved?) but I suspect the control mechanism is similar to the heavier duty units out there.

It's not particularly the transfer case I'm worried about, so much as the transmission, and your T case is unlikely to "bolt up" to a stronger trans as there will likely be a different spline trans output.

Yes, you could likely swap the input on the T case, but it would likely be easier to buy / trade for a trans & T case combo that already bolts together.

If you prefer a manual trans you might be able to get the apropriate combo out of a similar year Chevy / GMC pickup (heavy half ton, std 3/4 ton, especially anything with a tow package).

At least the connections should be similar for T case and speedometer.

Kinda surprised the 4.3 is giving you grief, but after this much time (17 years) everything can wear out.

Not to discourage you from diesel, but a smaller V8 Chevy (ie 305) would likely be a simpler swap, and will have more aftermarket support.

Had to say that, wouldn't be fair if I didn't at least mention it once (then you could even buy a wrecked similar year or newer truck for the engine, trans and T case, and as I'm sure you know they are quite a bit more common).

If you are intent on diesel and need one sooner than you can find a 4BT, might I suggest either the 4BD*T Isuzu or the OM series of Mercedes diesels.

As I understand it adapters are available for both, while I personally wouldn't want to put a 4BD in front of your trans or T case, I wouldn't have the same concern with the Merc, as I understand it they are physically smaller, lighter and smoother running than either the Cummins or the Isuzu.

Food for thought, best of luck. :)
 
#5 · (Edited)
I have actually found a couple sites that I could get a 4BT fairly quick on. I Would just have to rebuild them due to mileage, but rebuild kits are also redially avalible online. I have done some poking around on the web and found that a New Venture 4500 or a New Process 435 would be a good swap for a transmission (because they were both designed for heavy duty trucks, and the 4500 was even used to back the 6BT),but I cant find much for a transfer case that will bolt up even without the electronic shift.
 
#7 ·
I think your axles would work fine as long as you don't abuse them. There is always gonna be a weak link somewhere, but if you're just driving it normally, I don't really foresee any issues with the axles(if you don't abuse them). After all, they are not heavy duty "work" axles. As far as trans and t-case, I'm afraid I'm not much help,.....(Ford Guy)....

You should also fully understand the undertaking of such a swap.....She aint gonna just bolt right up.....lots of fab!! And for the "working man", this means she will be "down" for a while!
 
#8 ·
Ya I've been doing a lot of research on the swap and I know it will be down for a while. I was planning on having all the parts ready before I start the swap so I can minimize the down time (i.e. motor trans and tcase bolted together, suspension adjusted, get all the measurements for mounts and stuff before hand and have them made). I have another vehicle I can use in the mean time pluss I need some cash first haha so it wont happen till at least the summer. I also am not sure what I should do to the suspension to handle the extra weight of the motor and trans. Any ideas on what I should do to beef it up (Lift or stiffer shocks or springs)?
 
#9 ·
The best I saw for a first time (diesel) swapper was to get another of the same vehicle and Pre-fab the swap as much as possible.

I don't know if you have the room (real estate) for another and can find one cheap enough ("haul it off" preferably) it's not a bad way to go.

As far as the extra weight, new bushings and either lift kit torsion bars, or bars out of a heavier truck I would expect.

There have been many S10 based swaps pursued here, if you use the search feature here on the site make sure you select the "single content" tab on the advanced search feature.

Best of luck.
 
#10 ·
I would heavily consider a Kubota diesel for a swap and add a turbo in your situation. There's one on here for sale now with a turbo and few misc. parts for $1,500. The adapter is easier (from what I've read on here) to make yourself and your current drivetrain would probably be more reliable behind it than a 4BT. Plus the weight. 4BT's are heavy, 750ish lbs. The 4cyl. Kubota diesels are around 500lbs.ish.
 
#11 ·
If you have another vehicle to drive in the meantime, and you're not in a rush,.....build what you want man!....The whole purpose of a build is to be excited about the outcome, and to know you built what you wanted. Besides, the harder you have to work on it during the process, the more you will appreciate it when finished, and less likely to just tear the hell out of it. my two cents....
 
#12 ·
I do have another vehicle I can drive while my blazer is down. As I said before I plan on getting all the parts together and as much as I can fabed up before I start the swap so I can minimize down time. This project wouldnt happen for a little while because I need to get some more money (hopefully around summer). If anyone has any other issues I should look out for any information is welcomed openly.
 
#15 ·
Well, I'm doing a 4bt/Ranger as we speak,....and if I had it to do over again, I would go for nothing smaller than an F150. I'm not trying to discourage you at all, but you will have to fabricate and modify everything!! And I'm not just talking some motor mounts man,....I mean crap you never even dreamed of!! Unless of coarse you don't care jacking it up a mile in the air(both body and suspension). If what you have in mind is a 4" body lift, and 4" suspension lift, then it should be a piece of cake! But if you're like me, and don't want your truck to be stupid tall, then get ready, cause you're about to be a very busy man!
 
#16 ·
I was planning on doing about a 6" suspension lift and from what I've read about this swap that should give me the clearance I need. I plan on doing a lot more research before I start the project but as of now I havent run into anything that looks like it would be a problem to fabricate.
 
#17 · (Edited)
No, not a problem, just very time consuming. There are days when I stand back, look at the truck, and ask myself, What did I even accomplish today? And I worked all day!!. There are just so many little details that you don't even see along the way.....I would also almost guarantee you'll have to put some body lift on it as well...Trust me. Unless you're gonna cut the whole firewall and trans tunnel out and fab all of that too. Unless the S-10 has considerably more room than the Ranger. I've got 3" body lift right now, and will probably be 4" before it's over with.... I didn't want any lift at all, but it was either that, or cut the whole truck up.
 
#18 ·
Haha ya I know that feeling. I did a restoration on a 1969 Mercury Cougar and there were plenty of days that I felt that same way. I havent really looked at the tunnel for clearance, but the NV4500 (that I want to put in) is actually a smaller overall package than the NV3500 that is in there now so (theoretically) it shouldn't need any cutting. And the 4BT (if I remember right) is the same length if not a little shorter than the 4.3 that is in there now so i shouldnt need to cut the firewall any. The only place I would be close on clearance without a lift is the height of the motor because it is a couple inches taller than the 4.3 so (again theoretically) if I put a lift kit on it I should be good for clearance all around.
 
#19 · (Edited)
4bt is longer than the 4.3 and much taller. Is this a 2 door or 4 door blazer?

All that wight and heft on a small frame. I cant remember if the 96 frame is boxed behind the firewall or not. I know for sure the 98 and up frames are boxed to behind the cab on a s10 and boxed to the rear axle on the blazers. If its not boxed you may want to do some reinforcements.

6.5 and 6.6L gm diesels and 4bt's have been done in the past on S trucks but all I've seen (online) are ext cabs and 2 of those have had the frame lengthened and reinforced. Also those trucks have EXTENSIVE fabrication, custom suspension, no factory axles etc. You will run into driveshaft angle issues with the 2 door blazer. Its the shortest S truck frame they make.

I have an s10 and considered putting my 4bt into it. A tape measure and a few minutes time with knowledge of how much the 4bt weighs and I realized its not a good swap candidate. I still feel a kubota diesel into your existing drivetrain would be easier, cheaper and less downtime. I also think you'd be more happy afterwards with a very driveable stock suspension/drivetrain truck.
 
#20 · (Edited)
I talked to Manbearpig (the menber with the kubota) and it has about 110 less hp than my blazer. I would like to have around the same ammount of hp, but with a diesel that means way more torque than the current drive train will be able to handle so I will have to put a new transmission and most likely axles in either way.

Also the frame is boxed in after the firewall. The only place that I will have clearance problems is the height of the motor, from the front cross member where the 4.3l is mounted it would stick above the engine compartment about 6 inches. But I could fabricate a new cross member and custome motor mounts, along with a lift kit and it should fix the clearance problem. Also I think the height I found included having the turbo routed above the valve covers and I plan on putting an intercooler on it so that should take the height down a couple inches.
 
#22 · (Edited)
Sorry its the 2 door sport. So your saying even with only having 85hp the kubota would move my blazer around fine?

The numbers I got on the kubota are 51hp 110ft/lbs of torque at 2800rpm. That is 139 less hp and 140 less ft/lbs of torque compared to the 4.3l. I am not sure what upgrades would be avalible for the Kubota to be able to get even the torque close to 250ft/lbs.
 
#23 · (Edited)
Yup, in fact it would do very well. Plus your blazer is light. Add a turbo, which you should do anyway, and have an even better driver. Fuel mileage should be excellent as well depending on your current gearing and tire size.

Also the length of a 4bt, nv4500 and t-case wouldnt have good enough driveshaft angles to work in your 2 door blazer. Hence why most of the 6.5, 6.6 and 4bt S trucks are ext. cabs and have lengthened frames with custom supsnsion.

If your dead set on a 4bt I'd move into a different vehicle myself. That's what I did with my s10. Common sense said if I wanted to put my free 4bt into something it needed to be worth my time and not involve a bunch of custom expensive stuff.

I have to add: A 2 door 4x4 4.3 5spd. blazer is a very rare beast!
 
#24 · (Edited)
Manbearpig told me that with the turbo he has it should be about 80hp and 160ft/lbs. Im just not sure that is enough power for the Blazer. One of the main reasons I was thinking of doing this swap was more mpg's.

It is, but ive had so many problems that if I have any more with the motor It would almost be worth it to swap it out for something that will run much longer.
 
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