Steering wheel play after adjusting TRW box...

[StellaTariche]

Hi all,

My 2000 Monaco Diplomat has an adjustable TRW steering box.  I’ve adjusted it for no down stream play (Pittman arm to drag link to tie rods to kingpin)  but turning the steering wheel still gives me about 3/4” of play (without the Pittman arm moving).

Is there any way to tighten the U-joints (two I think) between the steering wheel and TRW box?

Is there any other area to address?

Thanks,

- John

 

 

 

[Bob Nodine]

16 hours ago, StellaTariche said:

Hi all,

My 2000 Monaco Diplomat has an adjustable TRW steering box.  I’ve adjusted it for no down stream play (Pittman arm to drag link to tie rods to kingpin)  but turning the steering wheel still gives me about 3/4” of play (without the Pittman arm moving).

Is there any way to tighten the U-joints (two I think) between the steering wheel and TRW box?

Is there any other area to address?

Thanks,

- John

 

 

 

Sounds to me like you still need to adjust the TRW. If you can move the steering wheel back and forth without the Pitman arm moving then slack still exists in the TRW. Use one hand to reach up and move the input shaft from the steering wheel from beneath the coach as you adjust the TRW. I almost forgot, one of the most important things is to make sure the wheels are pointing straight ahead and that the mark on the output shaft is aligned with the mark on the body of the TRW before you make the adjustment. By design there is slop on either side of the high spot in the TRW. If you make the adjustment while not on the high spot the TRW will not be adjusted correctly. When you align the marks the TRW is on the high spot. If when the TRW is aligned on the marks and the wheels are not pointing straight ahead then you muse leave the TRW on  those marks and adjust the drag link to get the wheels pointing straight ahead.

 

[Stingraysteve]

Hi  Bob, 

       Could you give me the part # of the  trw gear box?   Mine has play also.

thanks,

Steve

07 Endeavor 40sft 93 Chevy 4x4

[StellaTariche]

[Bob] “Use one handto reach up and move the input shaft from the steering wheel from beneath the coach as you adjust the TRW”

Thanks Bob, I read about aligning the marks, but didn’t realize the significance.  I’ll try it.

Q: do you remove the drag link from the Pittman arm before tightening the captured screw, do it with everything connected?

{StingraySteve] Here is a photo of my TRW box with the number: 

[Guest Cruzbill]

Would like to see a photo of the alignment marks. I adjusted my TRW several years ago, still no play-I didn't know about the alignment marks; Hope I hit it right. 

[Frank McElroy]

There are procedures in the Download Files.  Here is a link.  There are other files on the TRW gearbox that are even more detailed including the TRW Service manual.

 

[Guest Cruzbill]

Thanks Frank!

[Bob Nodine]

19 hours ago, StellaTariche said:

[Bob] “Use one handto reach up and move the input shaft from the steering wheel from beneath the coach as you adjust the TRW”

Thanks Bob, I read about aligning the marks, but didn’t realize the significance.  I’ll try it.

Q: do you remove the drag link from the Pittman arm before tightening the captured screw, do it with everything connected?

{StingraySteve] Here is a photo of my TRW box with the number: 

John,

You do not need to remove the drag link unless you are adjusting the position of the wheels in relation to the high spot marks on the TRW. The adjustment procedure on the TRW says to remove the drag link and test for play by moving the Pitman arm. I have not done that and Craig French, the guy who came up with the Sheppard to TRW swap has adjusted a large number of TRW boxes at rallies by moving the input shaft to test for play. He is the one who taught me how to adjust the TRW. In April of 2018 while camped at 1000 Trails Orlando I went to Harbor-Freight and picked up a few tools and adjusted our TRW before leaving on a trip out West. My steering still has zero play and that was over 10,000 miles ago. I swapped out our Sheppard for the TRW about 5 years ago and learned about the high spot marks the hard way. When I made the swap I could not get the drag link to line up with the Pittman arm so moved the steering a little to get the drag link onto the Pitman arm. Went on a test drive and did not see any improvement over the Sheppard and still had 1-1/2 inches of play. To say the least I was disappointed after spending over $800 for the upgrade. I talked to Craig and that is when he set me straight. Put the TRW on the high spot marks and adjusted the drag link so the front wheels were pointing straight ahead with the TRW on the mark and the drag link would slip on the Pitman arm. Night and day difference. So from time to time I try to help people so they don't make the same mistake I did. Some may think I am an arm chair quarter back but I have actually been off the bench and in the game.

[Bob Nodine]

20 hours ago, Stingraysteve said:

Hi  Bob, 

       Could you give me the part # of the  trw gear box?   Mine has play also.

thanks,

Steve

07 Endeavor 40sft 93 Chevy 4x4

Steve,

The first thing to do is to determine if you have the Sheppard or the TRW. Just about all the Diplomats built had the Sheppard but some had the TRW. The TRW is adjustable and the Sheppard is not. An easy way to tell the difference is by how the Pitman arm is attached to the steering box. The Sheppard has a large nut on the end of the output shaft and the TRW uses a bolt to clamp the Pitman arm to the output shaft.

The photo above is of a TRW steering sector. Notice the bolt thru the top of the Pitman arm. A Sheppard will not have that bolt.

The photo above is from Craig French and here is his words to describe the aligning marks.

"The TRW has a center indicator on the housing (see the bump) and output shaft (see the line). It does not matter where the pitman arm is indexed on the output shaft. The pitman arm might be indexed a few teeth left or right or CENTER . The TRW gear MUST look like this before adjustment begins or it will bind.
Most coaches need a mirror to be able to see the center alignment.
(Do not let my photo angle fools you, it is centered right out of the Weller box)"

If you have the Sheppard box and wish to convert to the TRW the best thing to do is to find the part number on your Sheppard box and call Weller. They can tell you if the swap is possible and which Pitman arm you will need. They can sell you the TRW and the Pitman arm. When you get the Sheppard out you can ship it back to them for a refund on the core charge. Here is the information you need to contact Weller.

John VanLaan
Team Leader Assistant
Steering Dept.
Weller Truck Parts
jvanlaan@wellertruck.com

1-616-724-3762

 

Edited August 8, 2020 by Bob Nodine

[Frank McElroy]

Although I have also adjusted TRW gearboxes without removing the drag link, one needs to be careful not to over tighten the shaft adjusting screw in the thinking that gee I still have a slight amount of steering play so I'll just tighten it a bit more.  If after making the adjustment you find that while driving the coach it takes more effort to move the steering wheel, you overtightened the shaft adjusting screw.  In practice, I stop turning the screw when there is no additional improvement in steering wheel play.  Also, it doesn't take much in turning the adjusting screw to change steering wheel play.  Yes, its critical that you check to make sure that the gearbox shaft is centered.  Being centered will have the least amount of steering wheel play.

[StellaTariche]

Hi All,

Update: Finally got another set of hands on the TRW steering box tools, and re-adjusted after centering first.

I also had a shop check the drag link (ok), tie rods (ok), king pins (ok).

The adjustment on the TRW is now tight, perhaps a little too much, but workable. More input is needed, but there is definitely less lash. BUT...

Problem: I still have lash from the wheel to the input of the TRW box.  After removing the plastic steering column shroud (so I could see the top of the TWR input shaft), the steering wheel still move about 1".  The pitman arm does not move at all when moving the steering wheel to check lash.  It looks like it is either (1) the very last universal steering column joint, or (2) the input shaft to the TRW box.

Which mean, I still end up constantly correcting the steering while driving, as the wheels guide themselves due to the lash.

1. Is this as good as it will get?
2. Is there a way to tell if it is the last universal joint on the column?
3. Will a new (reman?) TRW box fix the problem?

Any ideas greatly appreciated.

Thanks again,

- John

 

 

[Bob Nodine]

3 hours ago, StellaTariche said:

Hi All,

Update: Finally got another set of hands on the TRW steering box tools, and re-adjusted after centering first.

I also had a shop check the drag link (ok), tie rods (ok), king pins (ok).

The adjustment on the TRW is now tight, perhaps a little too much, but workable. More input is needed, but there is definitely less lash. BUT...

Problem: I still have lash from the wheel to the input of the TRW box.  After removing the plastic steering column shroud (so I could see the top of the TWR input shaft), the steering wheel still move about 1".  The pitman arm does not move at all when moving the steering wheel to check lash.  It looks like it is either (1) the very last universal steering column joint, or (2) the input shaft to the TRW box.

Which mean, I still end up constantly correcting the steering while driving, as the wheels guide themselves due to the lash.

1. Is this as good as it will get?
2. Is there a way to tell if it is the last universal joint on the column?
3. Will a new (reman?) TRW box fix the problem?

Any ideas greatly appreciated.

Thanks again,

- John

 

 

If I understand your photo you are pointing to the TRW and indicating the lash is inside the TRW and that the steering shaft moves back and forth with dead motion and the Pitman arm is not moving. If that is the case you may need to get the TRW rebuilt. Now if you are saying the steering wheel has dead motion or slop and the input shaft to the TRW is not moving when the steering wheel is cycled between both ends of the dead band then either you have a bad steering shaft or the universal joint is not tight on the spline shaft. The steering shaft is two pieces and has internal splines to allow for motion between the chassis and house. They have been know to become loose.  

[Stingraysteve]

On 8/8/2020 at 5:45 AM, Bob Nodine said:

Steve,

The first thing to do is to determine if you have the Sheppard or the TRW. Just about all the Diplomats built had the Sheppard but some had the TRW. The TRW is adjustable and the Sheppard is not. An easy way to tell the difference is by how the Pitman arm is attached to the steering box. The Sheppard has a large nut on the end of the output shaft and the TRW uses a bolt to clamp the Pitman arm to the output shaft.

The photo above is of a TRW steering sector. Notice the bolt thru the top of the Pitman arm. A Sheppard will not have that bolt.

The photo above is from Craig French and here is his words to describe the aligning marks.

"The TRW has a center indicator on the housing (see the bump) and output shaft (see the line). It does not matter where the pitman arm is indexed on the output shaft. The pitman arm might be indexed a few teeth left or right or CENTER . The TRW gear MUST look like this before adjustment begins or it will bind.
Most coaches need a mirror to be able to see the center alignment.
(Do not let my photo angle fools you, it is centered right out of the Weller box)"

If you have the Sheppard box and wish to convert to the TRW the best thing to do is to find the part number on your Sheppard box and call Weller. They can tell you if the swap is possible and which Pitman arm you will need. They can sell you the TRW and the Pitman arm. When you get the Sheppard out you can ship it back to them for a refund on the core charge. Here is the information you need to contact Weller.

John VanLaan
Team Leader Assistant
Steering Dept.
Weller Truck Parts
jvanlaan@wellertruck.com

1-616-724-3762

 

 

Just now, Stingraysteve said:

 

Thankyou Bob,  

I just got my trw gear box from Weller.  I appreciate your advice.

Steve

07 Endeavor 40sft

[highsierra37@att.net]

Post deleted

 

Edited February 18, 2021 by highsierra37@att.net

[StellaTariche]

UPDATED WITH SOME NEW SAFETY INFORMATION IN RED (BELOW)

Hi Joe,

I am having the same problem with rotational lash (just posted a question about it to the group). I was told it could be the "intermediate shaft" - again, have not climbed under to see if that exists and might be the problem. I have a properly adjusted TRW steering box (TAS 65). Still have about 1" of play at the steering wheel.

BUT, your problem and solution look interesting...

Couple of questions about the inner / outer shaft fix:  (I'm not under the rig - cause #%#$@* cold)

1. Removing the steering shaft from the steering box:  any tricks I should know?
2. How does said "pin" best come out? (will it be obvious, or something else tricky)
3. Which shaft should I be rotating with the vice grips (inner/outer)?
4. My welding skills need work.  Replacing with a slightly larger pin seems like a good idea. Will that also be obvious how to accomplish with the steering box in the rig, or must the steering box come out to have it machined?

 

Unfortunately according to TRW steering box experts, this is a VERY BAD AND POTENTIALLY DANGEROUS FIX.

I wrote another post with a summary of why...Please read!

Thanks for the help.

- John

John Taylor
Colorado Springs, Colorado
2000 Monaco Diplomat 38, one big wall slide

 

 

Edited February 17, 2021 by StellaTariche
new info about the fix - summary: fix is dangerous!

[StellaTariche]

Hi all,

I did some research with TRW about the "lock the inner and outer shaft" either with a larger pin or spot weld.

Unfortunately, this turns out to be a VERY BAD IDEA. 

(Original Post)

On 8/27/2020 at 11:53 PM, highsierra37@att.net said:

Another thing to check is the input shaft of the trw steering gear box. The input shaft has a small center shaft and a larger outer shaft that has the splines where the steering shaft connects . The center shaft and outer shaft are separate  pieces that are connected together with a pin. I had a  recent experience  where i found the play in the steering wheel was being caused by movement between the outer an inner shafts on the steering gear box input shaft.

To check for this remove the steering shaft from the steering gear box so you can inspect the input shaft on the steering gear box. Draw a line across the top of the shaft -  then use vice grip pliers to slightly rotate the shaft back and forth . The two shafts should be tightly locked together with absolutely no play at all. Just a very small amount of play between these two shafts can give an undesirable amount of play at the rim of the steering wheel .

If play is found between the two shafts an oversize pin can be installed or you might consider a very small spot of weld to permanently lock the shafts together. 

Again, unfortunately, this turns out to be a VERY BAD IDEA. 

Here is a summary from TRW:

Quote

 

Do not do what that forum said with the pin. That pin is designed to flex like that. That is one area where you want play.

That is the torsion bar. It works kind of like a torque wrench when it hits a certain torque it kind of flexes like a torque wrench. By messing with that pin or welding it you are eliminating that designed flex. That flex helps open and close a valve that gives you your power steering.

1. By messing with it You could cause the steering gear to have intermittent power loss(no power steering).
2. It could cause the pin to snap completely and you could lose your ability to turn completely.
3. You could over torque the wheel damaging the pump or gearbox significantly by having it locked in place.

So if you see a little bit of play there, that is ok -  it’s just doing what it was designed to do. It needs to flex to do what it is designed to do.

 

Here is a technical description of how the TRW steering box works internally:

 

tl;dr   SUMMARY: DON'T mess with the pin (torsion bar) or BAD THINGS MIGHT HAPPEN.

Hope that helps.

- John

 

[dl_racing427]

highsierra37@att.net

In light of the serious safety implications of this error, might I suggest you remove or edit your post to prevent someone from taking it out of context and making a deadly mistake?

[StellaTariche]

Hi David,

Good idea, but since I'm not the original author, I can't delete or edit it.

I did send a private message to the original author (Joe) about deleting it or changing it.

Thanks for the suggestion.

- John

Edited February 18, 2021 by StellaTariche

[highsierra37@att.net]

Steering wheel play after adjusting trw steering gear box

When i replaced my steering gear box with a trw gear box i found the input shaft to the gear box had an outer and an inner shaft. The two shafts are pinned together. I found there was loose play between the outer and inner shafts. The outer shaft would rotate about an eighth of an inch before the inner shaft would begin to move. This amount of free play at the shaft resulted in more than an inch of free play  at the steering wheel. With the engine running the steering wheel could be moved back and forth this amount before the wheels would have any movement. At the time it looked to me that the outer shaft was just an adapter to change the size of the inner shaft for different applications. I thought that this amount of looseness at the shaft could be reduced to decrease the free play at the steering wheel . My conclusion was that the box that i had installed had excessive looseness at the pin so i  removed the gear box and installed a replacement box that dos not have that looseness at the input shaft pin.

The recent post about the danger of locking the two shafts together is rather confusing as the two shafts are already locked together. The post also says that looseness at the pin is good - if that is so then free play at the steering wheel could not be eliminated.A better understanding of how the gear box works would be good However In light of this post no one should do anything but replace the gear box if it is not operating properly.

 

Joe Klasch  02 Dynasty   

Edited February 18, 2021 by highsierra37@att.net