Cummins 5 speed trans ???

[77crewcab]

Well I have finally decided to go with a 4bt in my Blazer, but I have a question on the 5 speed trans that came behind the 6bt in the dodge trucks. I know that they origionally came with a Getrag and then the NV4500. Just curious as to why people don't seem to want the Getrag? Is it a strength issue for the 6bt and a truck that does a lot of towing? Wondering if that is the problem, then would it be okay for a 4bt in a Blazer that doesn't see heavy towing?

 

[ccj8008]

Getrag

Had the Getrag in my 92 Dodge and it went out at >100,000 miles. If I had one free, I would use it. Pulled a 30 foot 5th wheel, good gearing, etc. The NP 205 that bolted up to it used huge u-joints (1480?).

I have a Jeep Cherokee with the 4BT turbo and a Cherokee with the GM 6.2 L diesel. The 6.2 is a much finer engine in my opinion. Quieter, better power,etc.

 

[Leper]

The Getrag is a good transmission. The problem is that the factory recommended fill level was 1 quart too low to keep all the bearings lubed properly. If you overfill it by 1 quart, you will be fine.

However..........If you try to sell that trans, you may get 50 bucks for it. If you need to buy one, it seems like they are made of gold. Not real cheap to rebuild.

The automatic trans option at that time was the 727 and later a trans with OD. I can't think of the designation right now. I'm thinking 518, but not sure for the Diesel. I have a 92 auto CTD Dodge as my tow rig right now. My point is that the Getrag guys wouldn't have an auto because they believe them to be inferior, not unusual, but it says something for the Getrags strength. You can use the first gen Dodges and pull all kinds of weight for all kinds of mileage and not have a problem. Stick a good South Bend clutch in it and upgrade the hydraulic system and you would be golden.

 

[77crewcab]

Cool so I shouldn't have any problems with it in a Blazer doing daily driver duties with occaisional light towing (6k or less) especially behind a 4bt. What about transfer case options? What came behind them stock and what can I use? I was hoping that a 208 from behind a 700R4 would work, but I also have a 203 from behind a th350. Will either of these work, or will I have to start looking for something else?

 

[oneofthefewbmx]

the OD immediately after the 727 was the 518 for gas and the 618 for diesel...i have the 618 in my truck and it is junk....but so is the getrag from what i hear....so its loose loose....if I were you i would go with a SIX-bt and a CHEVROLET transmission ....be it th400, 4l60, 4l80, whatever.....that is DEFINATELY the best choice....if I were going to do it all over again i would use the 4l60....in fact since my 618 just took a **** on my like 2 weeks ago i may just be going that route anyway ....why would you be going with a 4bt over a 6bt anyway???

 

[MaxPF]

Probably because a 6BT is really too heavy for the Blazers short half-ton frame.

To the OP - you could always look for a Dodge NV4500. Just make sure to install the fix for the 5th gear. Of course, if you already have the Getrag and it is in good shape I say run it till it croaks

OTOH, if you don't really need a 5-speed, there are a buttload of good 4-speed trannys out there that are more durable and way cheaper than any 5-speed box.

 

[77crewcab]

Well I origionally thought of just using the sm465 (4wd version of course) that came in the bread truck behind the 4bt. But then the thought of no overdrive, kind of kills that unless I also use a gearvendors. The GV option would be great I think, but I don't think that there would be enough room in a Blazer to run the 465, a t/c, and then the gearvendors and still have decent driv shaft length for the rear shaft. The getrag I can get complete from flywheel back for $100 just no tc. And I am not sure what tc will bolt up to it. The getrag was rebuilt by a local shop about a year ago, and I have driven it before it was pulled and it seemed just fine to me. So what would ya'll suggest?

 

[MaxPF]

I vote the SM465

If the Getrag was rebuilt a year ago, run it.

 

[rjfguitar]

the OD immediately after the 727 was the 518 for gas and the 618 for diesel...i have the 618 in my truck and it is junk....but so is the getrag from what i hear....so its loose loose....if I were you i would go with a SIX-bt and a CHEVROLET transmission ....be it th400, 4l60, 4l80, whatever.....that is DEFINATELY the best choice....if I were going to do it all over again i would use the 4l60....in fact since my 618 just took a **** on my like 2 weeks ago i may just be going that route anyway ....why would you be going with a 4bt over a 6bt anyway???

I think it was still the 518 behind the diesels, not positive, but pretty sure.

If you think a Dodge auto is junk, try a 4L60 and 4L80, and you'll see how fast you might as well toss them in the junk pile too....

A 700R4 (L60) doesn't even have a chance. 700's can handle some good horsepower, but they don't like torque. They are a good trans behind a small block....would last about 10 seconds behind a Cummins that builds peak torque at 1600rpm's....

Everyone praises how great they think that the 4L80E is....when they run it behind their big and small blocks, and sissy GM diesel....

Put a 6BT with some minor mods and see how long it takes for 700ftlbs of torque at 1600rpm to rip apart that 80E.

 

[DEMON44]

To answer the original question...........yes the getrag will be more than fine behind a 4b in a blazer. Don't even worry about it.


For the last 50,000kms I've been pumping anywhere from 400-600 rwhp and 700-1100ft-lbs (dependant on engine configuration) into my NV4500....lost the 5th gear nut pulling the Mountain passes in Wyoming enroute to Colorado.

outside of that its never given me a hint of wimper........upgraded input shaft and clutch though.

The NV4500 is more than tough enough......I'll put mine up against any 465 any day.

 

[77crewcab]

Okay cool! So does anyone know about the tc issue?

 

[rjfguitar]

Okay cool! So does anyone know about the tc issue?

Your best bet would be to buy a complete Getrag/NP205 together, it will be passenger drop like the GM version.

Far as I know, spline counts likely aren't the same between the output on the getrag and any GM trans. I could be wrong though.

 

[lectric80]

Far as I know, spline counts aren't the same between the output on the getrag and any GM trans.

This would be correct. The spline count should be 23, but there are some rare versions of the Getrag/NP205 that had a 29 spline input. These appear to be very rare, and would probably translate to some higher dollar value for those who know what they have.

 

[DEMON44]

I would agree to get a dodge t-case would be the easiest.

I thought all getrag - 205s were 29 spline male male. as I understood that was the only configuration for the 205 behind the getrag. I got one for $250 from a wrecker in a hick town near the Alberta/ Sask border. he told ne they were rare and still only charged me $250

 

[77crewcab]

Okay, thanks!

 

[lectric80]

I would agree to get a dodge t-case would be the easiest.

I thought all getrag - 205s were 29 spline male male. as I understood that was the only configuration for the 205 behind the getrag. I got one for $250 from a wrecker in a hick town near the Alberta/ Sask border. he told ne they were rare and still only charged me $250

That is possible, I had always been told that the 29 spline versions were rare. I know that the 23 spline is behind all the auto's, so it is possible that the Getrag 5 speeds all had 29 spline 205's.

 

[DEMON44]

I think they kept the same straight through......even the 241 behind my nv4500 is still 29spline 1 1/2" shaft.

I think rare being that its the only application that the 205 was configured like that. Its got the odd bolt on circle adapter for the male/male sleeve.

but with the goofy adapter it'll bolt nice to the back of a NV4500 or getrag.......if you need the Pass side drop use as is. if you need a Driver drop swap 205 input into Ford 205 case and bolt up.

 

[lectric80]

That makes a lot of sense, thanks Demon, now I know a bit more.