tspurlin

After the third rebuilt G360 left me stranded in Kansas with my dad coming to the rescue with his 6.0 power joker I decided swap to a NV4500 from standard transmission and install a CON OFE clutch. I had the G360 overfilled 1 qrt. w/ Royel Purple. That thing does not like to tow in overdrive and I want to be able to go down the freeway faster than 60mph when towing a trailer cause I got the motor to do it. No offense to the Getrag guys maybee its my driving skills but I want something bulletproof.

I did not see anything in the sticky for this only for the NV5600. Any body got some tips that might save me some headache? I will let chall know how it turns out.

Montana2x2

Make sure to fix the 5th gear problem in the NV4500 before you do the swap. As far as I know there are not any pickup sized thansmissions that you should tow with in OD.

tspurlin

Standard Transmission sells the NV4500 w/ a fully splined fifth gear.
I think the towing in overdrive thing is controversial cause I’ve heard tell some people say it should be now problem when towing loads within the confines of the rating of your vehicle. I think towing in overdrive is more of a Getrag problem than a NV4500 problem. Can you please explain why towing in a higher than 1 gear ratio puts more stress on the trans? I just want to be able to utilize the full potential of my Cummins and travel at higher, but safe, speeds than 60mph.

Montana2x2

Towing in OD causes more HEAT which in turn can cause bearing failures etc. The semi truck I drive at work has a trans temp gauge and when towing heavy, over 100,000# gross if I run in OD the trans temp quickly gets to 220 degrees and if I stay in direct I do not think I can get it over 180* I've been told the reason it creates more heat but honestly cannot remember the theory. A lot of class 8 trucks have gone to double OD in the search for fuel milage but I prefer running a higher rearend ratio and more gears like a 13 or 18 speed that ends in direct drive or a single OD for running empty. Sorry I could not be more help with the theory.

ghenges

The 1st gen Getrags are notorious for failed countershaft bearings from towing in overdrive.

The Getrag countershaft is about 3/4" in diameter and the bearings are no bigger than you'd find in a riding lawn mower.

A tremendous amount of torque is thrown off onto the countershaft in overdrive, the Getrag design simply can't take the pressure despite what the Getrag Luddites will claim.

The Getrag is a fine transmission if you never use the overdrive gear for anything other than light loads and light towing.

Hook up a 20,000# fifth wheel and you'll likely burn (they'll actually be blue if they're not disintegrated) the countershaft bearings within a couple thousands miles.

Swapped out the Getrag for a NV4500 several years ago and now can go on towing trips without the apprehension and constant fear the Getrag will fail again. The old Getrag carcass was sent to the scrap iron yard because of the hate for that trouble making tranny. Could've sold it on eBay and recovered a few bucks, but these Getrag 360's need to be removed from the face of the earth.

Riflemanusmc

WOW!!!!! I have never veiwed such an eloquet analogy of the G-rag tranny before. The nay sayers will soon be adding their response, I'm sure.

w250_93

I finally got my swap done last weekend, so far it seems like it was well worth it. I don't hear any gear rattle anymore and I can go through the gears a heck of alot faster.

HARDTIMES

Does the adapter for the transfer case bolt up to the nv4500? and you need a bellhousing from a 2nd gen truck that had the nv4500. O and do you need the plate that the bellhousing bolts to from a later year truck also?

ghenges

"Does the adapter for the transfer case bolt up to the nv4500?"
YES....The 29 spline transfer case coupler will slide right on to the NV4500 output shaft. A gasket between the tranny and 205 transfer case is recommended, fashion one out of gasket stock.

"do you need the plate that the bellhousing bolts to from a later year truck"
YES.... An adapter plate is required. Adapter plates are relatively plentiful, but be cautious in selecting one, adapter plates from crashed vehicles can be distorted and also have cracking (generally around the starter hole).

"and do you need a bellhousing from a 2nd gen truck that had the nv4500."
YES.... Again, 2nd gen bellhousings are relatively plentiful. Again, check it out carefully if it came from a crashed truck.
2nd gen trucks were also equipped with NV4500 and V10 gas engines, the bellhousing is the exactly the same and bear the same part number.

A transmission mount attaching to the NV4500 needs to be constructed. One can be easily made by welding angle iron to form a Z shape. The holes in the NV4500 are like an inch short of the holes in the transmission crossmember.

The original driveshaft will work without modification, but check to make certain there is enough slip length to accomodate suspension movement.

The worst part of these swaps often is the installation of the hydraulic clutch.
The old slave cylinder will not work.
Dodge produced slave cylinders of a couple different diameters so determining the proper clutch/slave cylinder combinations is to be considered.
I spliced the original master to slave cylinder that came with the bellhousing, not a great idea in that these things are near impossible to bleed out the air. About 20,000 clutch petal pumps later the thing finally works fine.
If you go with used, be certain to keep it stored in an upright attitude until installed.

Advance Adapters makes a bellhousing/adapter plate combination kit that has the transmission mount adapter included and will work with the original slave cylinder, also included is the shifter plate bracket for the transfer case shifting levers. Price of $350ish isn't bad compared to the cost of obtaining the individual parts described above.
Advance Adapters installation manual should provide a few ideas.

w250_93

I went with the AA adapter kit shown above, IMO the kit is the way to go cause u don't spend all that time looking for parts in a junk yard an like said above u don't have to worry about cracked or damaged parts.

torquefan

Specifically, on a 5 speed transmission, 4th gear is 1:1 ratio. In this gear the whole mainshaft is locked together and turns as an assembly. Power goes in at the front, and straight through to the back. There is no torque being transferred through one mainshaft gear, down through the countershaft, then back up to the mainshaft, like there is in 5th gear. Therefore, 4th gear is much stronger and will tolerate much heavier loads for many more miles than any other gear.

roxxx

I second the AA kit.... be careful when telling them about your T-case they sent me the wrong mount for the Shifter Ours is a gated one for the most part It is a pain to take of if you have everything in the truck

jesussaves

Its cheaper just to modify the getrag

copy and pasted from a guy at chrylsler from another thread ::


The bearing that fails is the rear main shaft bearing
What you have is a Timkin tapered roller bearing pressed onto the main shaft.....the race is then placed into the rear of the case partially sticking out. Then the tail shaft housing goes over the part of the race that sticks out pressing it down onto the cone....There are shims that go between the race and the tail shaft housing that adjust the bearing clearance..

The failure comes when the clearance is too tight (TOO MANY SHIMS)
This loads the bearing too tight.....When the trans heats up things expand...
This causes the race in the case to lock on the cone and rotate in the case...
This wears out the case and causes the trans to get real hot real fast...Then often times the case will crack between the main shaft and the countershaft bearing bores..... Party over !!!

The bearings in the Getrag are Timken tapered roller bearings just like the front wheel bearings. On front wheel bearings you adjust the clearance with the spindle nut....On a Getrag you stack thin shims.....For new bearings you want a +.006 preload . For used bearings you want .000 clearance.....

Back in the early 90's we were having problems with the remans getrag was sending us...I had about 20 or so that we tore down to find out what had happened...I found that all of them had +.030 to +.045 shim packs.....I thought that I was not calculating it correctly or that the failed units were too bad off to be accurate...
I went to the getrag reman plant way back when to get to the bottom of what the problem was..... I pulled 3 off of the line and tore them down to check the clearance....They all had +.030 to +.045 shim packs in them as well..... Oh sh** ! I called for the production manager ....We discussed my findings...He said that they set them up this way intentionally because they felt .006 was too lose and caused excess gear rattle during testing...OMG !!!

I promptly told him that he was to stick to the spec that WE told them to use and that I was going to write my report to my superiors that Getrag was the cause of the failures and should be back charged for the failures of the remans that Chrysler had had to eat in the previous 3 years!

For those of you that have had one of the Getrags apart . You may have noticed the the rear main shaft bearing race was excessively thick....
The reason for this was that when we were testing the very first Getrags we found that under excessive load that the standard race would split and crack the case...So we reduced the size of the cone and had Timkin make a special thick walled race....It worked and hence the reason for the strange heavy race...
The best thing to do is rebuild the Getrag PROPERLY and put it back in....
There is nothing wrong with the Getrag if you know how to build them !
I have written quite a bit on this subject in the past...Look up the posts...

I know that many think that the NV4500 is a better trans....But we did have the 4500 several years BEFORE the Getrags were used...The 4500 was only used for gas trucks originally....We used the Getrag because it was found to be a better trans during testing.....The 4500 was later used behind the diesels...It had a few small changes made to it before it was used in the diesels but that was it....
The 4500 replaced the Getrag for only one reason...cost !
Rebuilding the Getrag is not hard you just have to pay attention to details...
The Getrag's problems were few but vital... The things that made them fail were as follows...
1) OIL LEAKS
A) drain plug dripped , run out or run low on oil
B) No gaskets on early models , more leaks
C) pilot bushing failures,,, bronze was too soft
D) over loading , trailer too heavy
E) too much hp , turning up the fuel/air
F) overheating ruining the oil
G) wrong type of oil , no 90 weight in the Getrag ! !
H) not knowing how to shift , rattling the gears,, too high a gear at too low a speed

2) Poor assembly
A) setting shim packs too tight , Getrag even did this themselves at times
B) uneven shim packs between main shaft and countershaft causing tail shaft housing not to hit squarely
C) bell housing misalignment

In conclusion, I personally have never had a Getrag fail in any of my personal trucks nor have I ever had to rebuild one twice that I built,, I have seen them go hundreds of thousands of miles in fleet trucks without failures.....

If you still decide to replace it with some thing else I would be glad to buy whats left of your Getrag.. I could use the spare parts ...

Good luck and be sure to replace the pilot bushing. Preferably with a ball bearing... The flywheel will need to be bored out for this...I do my own but the guys at South Bend clutch do them all the time for people.....

As for the pilot bushing....Engineering knew it was not going to work before the first one left the plant...But if you did not haul trailers it would work long enough to get out of warrantee....Engineering wanted to use a ball bearing but . We were shot down due to cost ...
In 94 it was decided to go to a Torrington needle bearing...Great in theory but it just made matters worse....They ate the imputs alive....

As for the worn out ends on the imput shafts...What I do is put them in my cylinder grinder and make them round and back on center..Then I make a steel sleeve on the lathe and press it onto the shaft end.... Then I put them in my cylinder grinder again and finish them to the correct diameter for the ball bearing I am going to use ...The tolerance is .0001 ot centerline . And no your Craftsman engine lathe you got from dad is NOT going to do the job accurately enough !

Getrag G360 Gear Ratios
1st.........................................5.53:1
2nd........................................3.04:1
3rd.........................................1:67:1
4th.........................................1.00:1
5th............................................77: 1
Reverse..................................5.61:1

pulltilbroke

Wise words from mysteryman

There is nothing wrong with the getrag if its put together right and if the operator knows how to operate one

ghenges

What is submitted here is purely anecdotal.

1) Has anybody ever heard of lots of folks swapping a Getrag 360 into any another vehicle?
Advance Adapters doesn't have an adapter bellhousing to adapt the Getrag 360 to any other vehicle, Lakewood either.

2) Has anybody ever yanked out their NV4500 and replaced it with a Getrag 360?

3) Thousand upon thousands have yanked out Getrags and replaced them with NV4500's, are all these people wrong?

4) Thousands upon thousands more have sought out the NV4500 for rockcrawlers and such, no one even considers a Getrag, why?.


Again the Getrag 360 is a fine reliable transmission, ***IF*** 5th gear (overdrive) is not exposed to higher than stock horsepower (and that's the old 1st gen HP of 160, torque of 400), higher than stock torque or higher than recommended loading. The skinny 3/4" countershaft and inadequate sized countershaft bearings are incapable of handling anything more than the stock vehicle GVW rating.