OK so we got back from this wonderful adventure and I towed about 6000 pounds with it only 180 miles! The $4000 transmission I put in it blew the front seal out and dumped all the ATF out on the ground 180 miles from home. Two weeks and $1000 later the replacement transmission was put in by a shop there. Drove it home, hooked up to my 10,000# trailer, towed it a few miles to weigh it, was backing it into the driveway and SCREECH it quits going backward. Pulled it into the shop, dropped the ATF and trans pan and found a bunch of metal in the pan. TWO MORE WEEKS down, $200 worth of ATF and 2 days and its back together. Third transmission is a charm?????? I freakin hope so. These are supposed to be great overbuilt transmissions from Diesel Site. Not so far. I guess time will tell. Everything else seems to be working really well.
Super Raptor
- Thread starter klr2mato
- Start date
Suncoast or Goerend Brothers IMO. Stay away from the smaller or unknown builders unless they have a a REALLY good reputation over LONG time. Too easy for someone to quit or get fired and their product quality and/or service changes, in a small business.
A buddy of mine learned that the hard way with a "we are as good as the other guys" shop, said to rebuild on a budget. In about a year, he was replacing the transmission in his 2500 Dodge that was only a DD, no heavy towing, no drag racing, etc.. He could have bought a factory re-man with better results than that.
A buddy of mine learned that the hard way with a "we are as good as the other guys" shop, said to rebuild on a budget. In about a year, he was replacing the transmission in his 2500 Dodge that was only a DD, no heavy towing, no drag racing, etc.. He could have bought a factory re-man with better results than that.
I had the same happen to me... Eventually shipped it to Elite Diesel from Houston and had them put a full Built into it, never had a problem. 3rd tranny was the charm indeed but it came from a different company!
Finally! I think I finally have all the bugs worked out of this thing. Finally got a tranny that seems to be doing what it was intended to do. On the third try but it's done. THEN on my way home from hunting 10 days ago the turbo failed. BADLY! But certainly not as bad as it could have been. It was a stock turbo and I knew I was pushing it's outer limits. Well the envelope finally tore wide open. Broke the turbine wheel completely off the shaft. Didn't even touch the compressor wheel end thank God. SO $1500 later it now has an Aurora 3000 in it's place and WOW what a difference. It will now develop 42 pounds of boost (A lot):wings: Plenty of power and low EGT to boot! Can't wait to see how he does towing. Had a little trouble with the cruise control wiring but finally got that all sorted out and everything works as planned. Now for the fun part!
Hello all,
So after about 11,000 miles of nearly uninterrupted operation (except a couple quick tranny changes)
I have come to the conclusion that I made a fairly significant mistake! After some thought during the process of building this truck I decided to leave the rear end gears at their stock ratio (3.73/1). It isn't working. Plain and simple. The V-8 I pulled out is just not intended to operate in the same RPM range as the Cummins. At 75 MPH the current engine is turning just about 1850 to 1900 RPM in over drive. Just plain too slow. At 55 mph it is turning 1450. Barely off idle and WAY too slow. Not good for performance, mileage, drive-ability or the fact I have a tendency to drive WAY too fast anyway. SO what does this mean you ask? It means just about $1500 in parts and HOURS of work re-gearing both front and rear differentials. Live and learn. I think 4.10/1 gears will work pretty well. Should get the engine running in the RPM range it was designed for. Otherwise everything on this truck is working great. Anybody got any suggestions?
So after about 11,000 miles of nearly uninterrupted operation (except a couple quick tranny changes)
I have come to the conclusion that I made a fairly significant mistake! After some thought during the process of building this truck I decided to leave the rear end gears at their stock ratio (3.73/1). It isn't working. Plain and simple. The V-8 I pulled out is just not intended to operate in the same RPM range as the Cummins. At 75 MPH the current engine is turning just about 1850 to 1900 RPM in over drive. Just plain too slow. At 55 mph it is turning 1450. Barely off idle and WAY too slow. Not good for performance, mileage, drive-ability or the fact I have a tendency to drive WAY too fast anyway. SO what does this mean you ask? It means just about $1500 in parts and HOURS of work re-gearing both front and rear differentials. Live and learn. I think 4.10/1 gears will work pretty well. Should get the engine running in the RPM range it was designed for. Otherwise everything on this truck is working great. Anybody got any suggestions?Are you saying that 1900 RPM is too low for highway cruising?
IMO, that is exactly where you want to be. Many modern diesel engine begin their torque peak about 1600 RPM and that runs to about 1900 - 2000 RPM, then torque begins to drop off.
You may also wish to look into (VE) Volumetric Efficiency and (BSFC) Brake Specific Fuel Consumption at that RPM if you have the tools or can put your hands on them. Seeing EXACTLY how much fuel you are using in real world conditions at a given load and given RPM will tell you what you need to know. A friend's 2500 Dodge 6.7 cruises at 1600 rpm on the freeway due to 35" tires and 3.42 gears, IIRC. The lowest rpm with the highest torque is generally where you should see the best MPG.
If anything has been changed from the OEM configuration such as transmission ratios, tire size, etc., ensure that what you are reading on your tach is 100% accurate. This can be done using a CAN BUS reader or an OBD2 reader.
I would only want to go to a 4.10 gear wtih a 35 - 36" tire or for regular towing duty.
.02
IMO, that is exactly where you want to be. Many modern diesel engine begin their torque peak about 1600 RPM and that runs to about 1900 - 2000 RPM, then torque begins to drop off.
You may also wish to look into (VE) Volumetric Efficiency and (BSFC) Brake Specific Fuel Consumption at that RPM if you have the tools or can put your hands on them. Seeing EXACTLY how much fuel you are using in real world conditions at a given load and given RPM will tell you what you need to know. A friend's 2500 Dodge 6.7 cruises at 1600 rpm on the freeway due to 35" tires and 3.42 gears, IIRC. The lowest rpm with the highest torque is generally where you should see the best MPG.
If anything has been changed from the OEM configuration such as transmission ratios, tire size, etc., ensure that what you are reading on your tach is 100% accurate. This can be done using a CAN BUS reader or an OBD2 reader.
I would only want to go to a 4.10 gear wtih a 35 - 36" tire or for regular towing duty.
.02
Seabass
Idiot
I have a 97- OBS truck. 7.3, 5 spd, 4.10, 35" tires. I am very happy with the combination. I didn't like the 4.10's until I put the tall tires on. Thing spun around 2,500 rpm at 70mph in 5th gear. It was good for country cruising though. Since I haul horses and other things I do work my truck. I really don't think I would want anything any taller than 4:10's. i think 37's would hurt my towing ability. Hope this doesn't muddy the water too much.
(Are you saying that 1900 RPM is too low for highway cruising?)
No I'm saying cruising down the highway at 55mph turning 1400 RPM is too low. Trans and rear end ratios are stock and it has 35x12.50x16 Goodrich KO2s on it. At 65 it's still only turning 1550 to 1600 tops. By the time this thing gets to 1900 your doing close to 80. Just too fast for me. Especially when towing my 10,000 pound trailer. If I take it out of over drive it goes to just about 1900/65 mph.ANY TIME I am in any traffic at all going less than 55 I have to take it out of OD.
Your absolutely correct. Peak torque in stock condition for this 5.9L 24 valve is right at 1600. Which is fine for getting it up to highway speed. Peak Horsepower is between 1800 and 2700 RPM. It's odd I have been experimenting with the Blue Chip Diesel fuel management system. It does just the opposite of what I thought it would do in terms of mileage. With the horse power turned all the way down it get's just about 15.5mpg. With it turned UP to it's mazimum 63% fuel increase it is getting just about 17.1 consistently. It has a few upgrades in terms of performance. It has a stage 3 Colt "Big Stick" cam and lifters, A 4 inch turbo back exhaust behind an ATS 3000 turbo as well as large K&N air filter.
I did another experiment the other day. I set the cruise at 65 on absolutely flat straight road, let the pyro temp stabilize at 750 degrees cruising with no added load. Then all I did was kick it out of over drive. The EGT immediately dropped 150 degrees to 600. If I am pulling a hill with just the truck and put my foot in it and hold it there it will go to 1100 degrees within 60 seconds. NO smoke that I can see. Of course it does build 42 pounds of boost. Theory is more RPM=more air=lower EGT which is a good thing.
I have no tools to help me with VE or BSFC. I was thinking of taking it out to the valley and putting it on a chassis dyno. Might give me some good info. I really don't want to spend $1500 OR do all that work if I don't have to!
( Hope this doesn't muddy the water too much.) No worries all information is welcome here man. I just want it right.
No I'm saying cruising down the highway at 55mph turning 1400 RPM is too low. Trans and rear end ratios are stock and it has 35x12.50x16 Goodrich KO2s on it. At 65 it's still only turning 1550 to 1600 tops. By the time this thing gets to 1900 your doing close to 80. Just too fast for me. Especially when towing my 10,000 pound trailer. If I take it out of over drive it goes to just about 1900/65 mph.ANY TIME I am in any traffic at all going less than 55 I have to take it out of OD.
Your absolutely correct. Peak torque in stock condition for this 5.9L 24 valve is right at 1600. Which is fine for getting it up to highway speed. Peak Horsepower is between 1800 and 2700 RPM. It's odd I have been experimenting with the Blue Chip Diesel fuel management system. It does just the opposite of what I thought it would do in terms of mileage. With the horse power turned all the way down it get's just about 15.5mpg. With it turned UP to it's mazimum 63% fuel increase it is getting just about 17.1 consistently. It has a few upgrades in terms of performance. It has a stage 3 Colt "Big Stick" cam and lifters, A 4 inch turbo back exhaust behind an ATS 3000 turbo as well as large K&N air filter.
I did another experiment the other day. I set the cruise at 65 on absolutely flat straight road, let the pyro temp stabilize at 750 degrees cruising with no added load. Then all I did was kick it out of over drive. The EGT immediately dropped 150 degrees to 600. If I am pulling a hill with just the truck and put my foot in it and hold it there it will go to 1100 degrees within 60 seconds. NO smoke that I can see. Of course it does build 42 pounds of boost. Theory is more RPM=more air=lower EGT which is a good thing.
I have no tools to help me with VE or BSFC. I was thinking of taking it out to the valley and putting it on a chassis dyno. Might give me some good info. I really don't want to spend $1500 OR do all that work if I don't have to!
( Hope this doesn't muddy the water too much.) No worries all information is welcome here man. I just want it right.
Tach and speedo are both verified and accurate. By the way I have had this thing to 137 mph when I took my foot off the throttle it was still pulling hard. I slowed down because it overspeeded the turbo. That's when I got ride of the stock turbo/Wicked Wheel combo and put the ATS turbo on it. WOW what a difference.
Sorry, misunderstood your "too fast" (speed) to be "too many rpm" (at x speed)
I would certainly not want to cruise at 1400, but that sucks you have to change the diffs, after you have done so much work already.
Hopefully you can sell the factory chunks or maybe find someone to swap with you. A couple of the Toyota guys that I rock crawl with are actually going to double and triple transfer cases with 4.10 diffs because they are breaking 5.29 and 5.71 diffs too easily.
There is certainly something to be said for having the proper gear ratio for the application.
I would certainly not want to cruise at 1400, but that sucks you have to change the diffs, after you have done so much work already.
Hopefully you can sell the factory chunks or maybe find someone to swap with you. A couple of the Toyota guys that I rock crawl with are actually going to double and triple transfer cases with 4.10 diffs because they are breaking 5.29 and 5.71 diffs too easily.
There is certainly something to be said for having the proper gear ratio for the application.