np205 fit issues?

[Yeller]

Any chance you could post a pic of the GM support rod from the Bell to transfer case? I did some searching and haven't found it. Thanks!

The rod is there to add Suport for the front driveshaft impacting the front output. I’ve never seen one break from not having that that didn’t have a massive collision involving front suspension failure.

 

[dieselfarmer]

The rod is there to add Suport for the front driveshaft impacting the front output. I’ve never seen one break from not having that that didn’t have a massive collision involving front suspension failure.

Interesting. Given the weight of the NP205, I thought it would be smart to have some rear support for it (other than the trans cross member), but I see the argument about flex and binding of the frame in some situations, especially off road.

Do you think if I use grade 8 bolts (shown in the pic) between the trans housing extension to NP205, that should be sufficient with use of a good solid trans cross member?

Should I upgrade the original 5 bolts from the transmission to trans housing extension? I'm not sure what grade bolt is used in that application.

 

[rocknhorse76]

I run a 4R70W/Titan/205 combo and have two crossmembers. Both of them are poly mounted at the frame ends as well as at the center points where they attach to the trans adapter and rear of the 205. No issues with flex, and I use my Bronco mainly offroad.

 

[Yeller]

Interesting. Given the weight of the NP205, I thought it would be smart to have some rear support for it (other than the trans cross member), but I see the argument about flex and binding of the frame in some situations, especially off road.

Do you think if I use grade 8 bolts (shown in the pic) between the trans housing extension to NP205, that should be sufficient with use of a good solid trans cross member?

Should I upgrade the original 5 bolts from the transmission to trans housing extension? I'm not sure what grade bolt is used in that application.

It will be just fine with the existing bolts

 

[gnpenning]

Any chance you could post a pic of the GM support rod from the Bell to transfer case? I did some searching and haven't found it. Thanks!

The first picture is the bell housing end the 2nd picture shows the whole thing and the 2 holes on the tcase side.

GM started using a L shaped bracket on the tcase and one on the frame with donuts between them. They later switched to the rod shown. I don't recall the years of the change for sure. I do know any square body with a manual didn't use the rod. My 77 SQ body came with the brackets and my 82 K30 and 86 have the rod, both automatics. All are from the factory.

 

[Yeller]

Here’s a couple of pics of an NP203 with a single mount and on a much weaker cased T350. Guess what that 203 weighs???? 195#!!

For reference the range box weighs 85# so and 203/205 doubler weighs 240# +\-

It also has the torque rod installed. Had to dig deep in the old treasure hole for this one, that is a concrete floor under there somewhere

For those really paying attention that is an international harvester divorced 205 hiding behind that trans and tcase.

 

[dieselfarmer]

Here’s a couple of pics of an NP203 with a single mount and on a much weaker cased T350. Guess what that 203 weighs???? 195#!!

For reference the range box weighs 85# so and 203/205 doubler weighs 240# +\-

It also has the torque rod installed. Had to dig deep in the old treasure hole for this one, that is a concrete floor under there somewhere

For those really paying attention that is an international harvester divorced 205 hiding behind that trans and tcase.

Thanks for that nice old pic!
Looks like the torque rod is not below the t case, it is on the side. How does it do any good located on the side? Is the rod just meant for stability?

 

[nvrstuk]

Fit between the frame rails?
Yes, without modifications.

Gearing?
Low range is only 1.96 to 1, and there is no low gear set made for the Ford version.
Your only option for lower gearing is a doubler gearbox, those add several inches of length to the drivetrain.

The other issues are:
It is heavy so needs extra support.
If you use it with modern Ford round mounting flange transmission a notch needs to be cut in the flange to clear one of the shift rails.

Actually doublers are shorter than the OE adapters that mate the trans and t-case.

An example is my KluneV at 6"

The Titan bolts to a 4r or ZF and an NP205 and is only 5.3" long. Stronger than any doubler out there. You'd love it

Had one of each. Rocknhorse has the Titan now. AMAZING pkg

 

[Yeller]

Thanks for that nice old pic!
Looks like the torque rod is not below the t case, it is on the side. How does it do any good located on the side? Is the rod just meant for stability?

Not an old pic, took it yesterday

It is just to provide stability, really not an issue for anything running coil springs. Remember the trucks those came from were leaf spring and the tcase took a beating from the front driveshaft. There’s a million of them running around with out it so how relevant it is, is doubtful. I always laughed taking them off, their are 2ea 5/8 (15/16 wrench) holding it to the side of the case and a single 3/8 (9/16 wrench) bolt holding it to the bell housing. One side way over kill and one not so much. I don’t feel they really do much.

 

[nvrstuk]

Not an old pic, took it yesterday

It is just to provide stability, really not an issue for anything running coil springs. Remember the trucks those came from were leaf spring and the tcase took a beating from the front driveshaft. There’s a million of them running around with out it so how relevant it is, is doubtful. I always laughed taking them off, their are 2ea 5/8 (15/16 wrench) holding it to the side of the case and a single 3/8 (9/16 wrench) bolt holding it to the bell housing. One side way over kill and one not so much. I don’t feel they really do much.

IS this similar to what Ford tried doing to stabilize the C4 with that funky rod they used for a while??? Curious is all.

 

[gnpenning]

The 2 large holes in the rod is a hold over from the frame mount brace and GM keeping everything the same. No need to change the housing side bolt holes. The time you find out if it is needed or not for your application is always after the damage is done. Not sure what the downside is, unless you are really into saving weight, all 5lbs.

Again, the rods were not commonly used on manual transmissions from the factory since they were cast.

Pick what works for you and go for it. No wrong answer.

 

[jamesroney]

Not an old pic, took it yesterday

It is just to provide stability, really not an issue for anything running coil springs. Remember the trucks those came from were leaf spring and the tcase took a beating from the front driveshaft. There’s a million of them running around with out it so how relevant it is, is doubtful. I always laughed taking them off, their are 2ea 5/8 (15/16 wrench) holding it to the side of the case and a single 3/8 (9/16 wrench) bolt holding it to the bell housing. One side way over kill and one not so much. I don’t feel they really do much.

Agree about the function of that rod.

Those "stabilizer" rods are only there on aluminum cased automatic bell housings, because the T350 will crack in that location. There are only 2 ea giant 5/8 bolts holding it to the t-case because those holes were cast in when the t-case had a torque reaction mount on the side. So the holes were just "available." I have no doubt that it was a late engineering "upgrade" discovered during reliability testing.

The rod as it is configured cannot carry bending moment, and has virtually no column strength. So it is basically a tensile member that provides strength in pulling. I am convinced that the slip yoke on the transfer case applies a thrust load from the front axle that causes the transfer case to want to move fore and aft, and that Truss rod prevents that flexing. I do agree that in 90% of use cases, (and 100% of use cases in Early Broncos) the truss rod does nothing.

Your notion that the suspension travel, combined with a front pivot leaf spring would create that thrust load is compelling. No shortage of broken AX15 bells in leaf spring Toyota Hilux pickups that could have used that rod.

 

[Yeller]

@jamesroney yes they could

The truck with leaf springs fixed at the bumper created huge amounts of motion in the driveshaft slip. They did ride better but rock crawled worse. Very common to see broken driveline components from the driveshaft bottoming out hard.

 

[jamesroney]

@jamesroney yes they could

The truck with leaf springs fixed at the bumper created huge amounts of motion in the driveshaft slip. They did ride better but rock crawled worse. Very common to see broken driveline components from the driveshaft bottoming out hard.

Maybe, but I don’t think the ones I fixed ever fully collapsed the yoke. I THINK that the constant motion while under load pushes and pulls on the case enough to fatigue the bell. 100% agree that when you bottom the yoke, ugly things happen, but the standard press-in grease cup plug on the spicer slip yoke should get knocked out first.

I’ve inherited a couple of NP-241-OR cases with broken off front halves from TJ’s that bottomed. It’s not pretty.

 

[dieselfarmer]

There is a ton of good info on this forum - thanks for the comments.

The pics attached show my "newly designed" np205 cross member which is built with the fox mustang mount in the center, bolting to three bolts on the np205 -- it also bolts to the steel located on the inside of the frame rail so it can be easily removed to service the np205 trans case.

I am keeping the cross member with the fox mount on the 4r70w tranny as well. Hopefully both of these mounts, one on the trans on one of the t case, with the rubber pivot in the center, will serve me well. Time will tell.

Included a pic of the fox mustang transmission mount that I used - it can be purchased from rockauto or any of the vendors.

 

[rocknhorse76]

There is a ton of good info on this forum - thanks for the comments.

The pics attached show my "newly designed" np205 cross member which is built with the fox mustang mount in the center, bolting to three bolts on the np205 -- it also bolts to the steel located on the inside of the frame rail so it can be easily removed to service the np205 trans case.

I am keeping the cross member with the fox mount on the 4r70w tranny as well. Hopefully both of these mounts, one on the trans on one of the t case, with the rubber pivot in the center, will serve me well. Time will tell.

That’s quite similar to the setup I’ve been running for a few years now.

 

[dieselfarmer]

That’s quite similar to the setup I’ve been running for a few years now.

Rocknhorse76, it looks like you have put it through the paces based on the description of your ride - thanks!!

 

[rocknhorse76]

Rocknhorse76, it looks like you have put it through the paces based on the description of your ride - thanks!!

Yeah I definitely don’t baby it lol

 

[dieselfarmer]

Here is a nice looking support bracket design if you’re not interested in fabricating one.

https://www.tmrcustoms.com/products/transfer-case-support-kit-np205

 

[rocknhorse76]

Yeah I definitely don’t baby it lol

Here is a nice looking support bracket design if you’re not interested in fabricating one.

https://www.tmrcustoms.com/products/transfer-case-support-kit-np205

That’s the one I used.