Question on DP-D1 shimming

I am brand new to this forum, and am hoping someone can help me work through this.
I found metal shavings in my DP-D1 outdrive so I tore it down and it appears that the lower unit pinion gear retaining nut is hitting the back of the bearing cage on the inner shaft gear and clipping the corners off of the nut. I decided to replace all bearings in the lower unit since the drive is 20 years old, and the vertical shaft bearings were worn.
While going through the shimming procedures, the shimming for the 2 drive gears worked out very close to the shims that were in there originally so I am confident they are OK. However following the procedure for the vertical shaft, the numbers work out to needing a -.19mm shim. The issue seems to be the H stamping is beyond the tolerances. If you go by their nominal numbers in the procedure you have 277mm for the housing measurement, and 217.5 (shaft) + 60 (gear) = 277.75 for the vertical shaft.
This would require .75mm of shims. The H stamping on my housing is 99, and the gear stamping is 049. This results in 277.799 for the shaft, and 277.99 for the housing. Rounding the shaft number and subtracting the H measurement from the shaft measurement according to the procedure results in 277.80 - 277.99 = -.19mm. There were 2 0.2mm and 2 0.05mm shims in the shaft housing when I disassembled it.
Any help in reconciling this would be appreciated.

I am brand new to this forum, and am hoping someone can help me work through this.
I found metal shavings in my DP-D1 outdrive so I tore it down and it appears that the lower unit pinion gear retaining nut is hitting the back of the bearing cage on the inner shaft gear and clipping the corners off of the nut.
That would be the "drive" gear. (a pinion gear would refer to a ring and pinion set, for example!)

I decided to replace all bearings in the lower unit since the drive is 20 years old, and the vertical shaft bearings were worn.
There are 3 sets of vertical shaft bearings.
You'll see a set of loose needle bearings surrounding the "drive" gear....... you'll see one angular contact bearing above those....... and you'll see one tapered roller bearing above that one.
The tapered roller bearing race controls the "drive"-gear-to-"driven"-gear contact once under dynamic loads.


While going through the shimming procedures, the shimming for the 2 drive gears
Did you mean to say; the 2 driven gears?

worked out very close to the shims that were in there originally so I am confident they are OK.

However following the procedure for the vertical shaft, the numbers work out to needing a -.19mm shim. The issue seems to be the H stamping is beyond the tolerances. If you go by their nominal numbers in the procedure you have 277mm for the housing measurement, and 217.5 (shaft) + 60 (gear) = 277.75 for the vertical shaft.
This would require .75mm of shims. The H stamping on my housing is 99, and the gear stamping is 049. This results in 277.799 for the shaft, and 277.99 for the housing. Rounding the shaft number and subtracting the H measurement from the shaft measurement according to the procedure results in 277.80 - 277.99 = -.19mm. There were 2 0.2mm and 2 0.05mm shims in the shaft housing when I disassembled it.
Any help in reconciling this would be appreciated.



The nut that secures the "drive" gear should not be able to contact any other components.
I would first find out what has caused this!

Secondly..... the over-all shimming procedure is very critical, and is best if performed by an experienced Volvo Penta Tech.
Please note that a gear set alone will run you well over $1,800, plus the new bearings!

As for shimming above the vertical shaft's tapered roller bearing "race", this involves taking an A and B dimension.
Your OEM work shop manual will explain this.
Basically, it is simple math.

Rickardo,

Thank you for your response.
I understand that the shimming is critical which is why I posted this thread. I am replacing all of the bearings in the lower unit including the 3 that you mentioned. The gear set was replaced around 8 years ago and the wear pattern on the teeth looks correct so I do not intend to replace the gears.
Going through the shimming procedure for the large bearings on the inner and outer shaft driven gears, the numbers for each came out to exactly match what was behind the races of the bearings I am replacing so I am fairly confident they are correct.
However, as I posted, the numbers for the shims under the second bearing up on the vertical shaft VP part number 183374 (SKF 7205BEP) do not work out according to the manual shimming procedure unless I am mis-interpreting the number stamped on the drive gear. The number on the gear is 049 which I would interpret as +0.049mm according to the manual. Here is a summary of the steps to determine the vertical shaft shims in the DP-D1 shop manual:
H nominal = 277mm
H stamping = 99 which would be 0.99mm
H measurement would be 277.99mm

for the vertical shaft:
Pinion gear (drive gear by your definition) nominal is 60mm
Pinion (drive) Calculated = 60mm +0.049 = 60.049mm
Vertical Shaft Nominal = 217.75
Pinion (drive) Calculated 60.049
Vertical shaft Calculated = 217.75 + 60.049 = 277.799

Calculated Shims = Vertical Shaft Calculated - H measurement which would be 277.799 - 277.99 = -0.191

These are the calculations right out of the shop manual using my H value and the stamping on the gear.
Clearly negative shimming does not make sense. The value 049 is consistent on all 3 gears. Could I be mis-interpreting it? The shims that are currently in the drive add up to 0.5mm. If I use the shim values and the H value and work back to the pinion gear, the Pinion (drive) Calculated comes out to 60.74 which would indicate a stamped value of +74 on the gear which is not even close to 049.
I understand that the shimming can be adjusted based on the shaft end play so perhaps this is where the discrepancy came in, but it is very disconcerting that the procedure in the manual is not making sense based on the H value and gear stamping in my drive.

I agree that I have to find the reason that nut was interfering with the bearing cage. Both the roller bearing just above the drive gear and the second bearing up (SKF 7205BEP) were badly worn which I assume could be one possibility. The only other possibility I can see would be improper shimming of the bearing on the inner shaft that it is interfering with, and I have not checked that yet.

Thanks for any help you can give me in clearing this up.

CaptBobS

You also have to check the wear pattern the figures just get you close you need to maintain proper preload and backlash as well as have the proper gear contact pattern. Are you sure the upper gearbox is not dropping fragments into the lower gearbox? How old is the split ring keeper for the verticle shaft?

kimcrwbr1,

I replaced the upper gear box gears and all of the bearings in the upper gear box 2 seasons ago. The preload was set according to the procedure in the manual, and the end play measurements were in tolerance. I did disassemble it to see if the issue could be coming from there, but there was no real evidence of metal in the upper bearings when I rinsed them, and the wear pattern that is starting to show on the gears looks correct. I will be putting a new crush sleave in it and go over the entire setup again before I put the drive back together.

Are you refering to the split ring keeper on the vertical shaft in the upper housing? If so, that is original to the drive which is a 1997 DP-D1.
Would that influence this issue?

Thanks
Bob S

The split ring keeper if brass should probably be replaced now since it is probably brass. The stainless one will last alot longer I believe Ricardo has them. To check end play you pull press the bearings together for the verticle shaft and measure the gap between the nut and the top bearing. You want no more than .020 inches end play on the shaft. There are four different nuts available if you cannot get the end play within spec .006"-.020" with one of the nuts you probably need to replace the bearings.

.....................................

captbobs said:

Are you refering to the split ring keeper on the vertical shaft in the upper housing? If so, that is original to the drive which is a 1997 DP-D1.
Would that influence this issue?
In my opinion........ NO!

(read below...... there's more to this!)

Thanks
Bob S

Click to expand...

kimcrwbr1 said:

The split ring keeper if brass should probably be replaced now since it is probably brass.
1996 was the last year for the AQ series Gasoline Engine stern drives. (the diesel engine AQ series ran into year 2000)
After the 280 and the 1st gen 290, the vertical shaft diameter was increased, as well as the split ring keeper becoming stress-proof steel.


The stainless one will last alot longer I believe Ricardo has them.
I have the early version replacements that were machined from stress-proof steel. ( Stainless Steel would be too soft! )
In other words...... my SPS split ring keepers work as a replacement only for the "brass split ring keepers"!
(for the smaller diameter vertical shafts).

Click to expand...

kimcrwbr1, Ricardo,

I am afraid I am not familiar with the drives earlier then the DP-D1, so I suspect that lack of history is creating some of the misunderstanding.
If I understand your terminology correctly, a split ring keeper would be something that goes on the shaft to retain 2 half circle rings in a groove, and there is nothing like that on the lower unit vertical shaft. There is one on the vertical shaft in the upper unit, but as Ricardo pointed out that should have no influence on this measurement since the coupling between the upper and lower shafts is a splined sleve which should have no interference between the 2 shafts.
It sounds like we are talking about 2 different shaft designs, so to try to clarify what I have here is a description of the vertical shaft I am talking about:
Starting at the bottom, there is what appears to be a hardened retaining nut that holds the drive gear in place. Going up the shaft there is a race just above the drive gear for the roller bearing. Going towards the top there is a roller bearing SKF 7205BEP. Above that is what the manual refers to as the thin spacer, followed by the roller bearing (VP part 11072 - SKF 31305). This is followed by what the manual calls the thick spacer, and finally a retaining nut which is installed with a spanner wrench. Consequently I don't know what you are refering to when you mention a split ring retainer or 4 different nuts that are available.
Sorry for the confusion; pictures work a lot better then words for this type of discussion. The shims I am looking to address are those between the lower unit housing and the roller bearing SKF 7205BEP which determine how far into the bottom of the housing that the drive gear extends.

Bob S

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captbobs said:

kimcrwbr1, Ricardo,

I am afraid I am not familiar with the drives earlier then the DP-D1, so I suspect that lack of history is creating some of the misunderstanding.
Possibly! I'll do my best to help with that!

If I understand your terminology correctly, a split ring keeper would be something that goes on the shaft to retain 2 half circle rings in a groove,
That is correct!
All AQ series transmissions use this style keeper at the lower area of the transmission's vertical shaft!

and there is nothing like that on the lower unit vertical shaft.
See above. This would apply to the transmission ONLY!

By the way...... the AQ series stern drives are a 3 pc drive.
...... Upper unit = Transmission...... this is where the actual Neutral, FWD and REV gear selections are made!

...... The Intermediate Housing supports the Transmission and the Lower Gear Unit!
The Intermediate Housing is attached to the Transom Shield via a "Main Suspension Fork".
It is allowed to articulate via what is referred to as a "Pivot Tube".

....... The lower gear unit attaches to the Intermediate Housing! This Intermediate Housing directs the exhaust flow to and out of the lower gear unit case.


There is one on the vertical shaft in the upper unit, but as Ricardo pointed out that should have no influence on this measurement since the coupling between the upper and lower shafts is a splined sleve which should have no interference between the 2 shafts.
Think of this shaft as though it "floats".... so to speak.
Via a total of 4 caged needle bearings, the shaft centers and supports the two large "Angular Contact Bearings".
The "split ring keeper" that you have will be made from "Stress Proof" steel.

It sounds like we are talking about 2 different shaft designs, so to try to clarify what I have here is a description of the vertical shaft I am talking about:


Starting at the bottom, there is what appears to be a hardened retaining nut that holds the drive gear in place. Going up the shaft there is a race just above the drive gear for the roller bearing.
Correct!
These are needle bearings that surround and support the "Drive" gear!

Going towards the top there is a roller bearing SKF 7205BEP.
This is another version of what we refer to as an "Angular Contact Bearing". (look closely at it....... you will see the difference from that of a standard ball bearing)
Once the drive is installed and has been shimmed properly, and is put under load, this bearing pretty much just goes along for the ride!


Above that is what the manual refers to as the thin spacer, followed by the roller bearing (VP part 11072 - SKF 31305). This is followed by what the manual calls the thick spacer, and finally a retaining nut which is installed with a spanner wrench. Consequently I don't know what you are refering to when you mention a split ring retainer or 4 different nuts that are available.
You have describing parts of the lower gear unit.
The split ring keeper, the 4 different LH Nuts that you NOW talk about, are at the transmission!

Sorry for the confusion; pictures work a lot better then words for this type of discussion. The shims I am looking to address are those between the lower unit housing and the roller bearing SKF 7205BEP which determine how far into the bottom of the housing that the drive gear extends.
Yes..... I believe that I addressed this in post #2 by suggesting that you see the OEM instructions regarding the A and B dimensions!

As for the work shop manual........ NOT Seloc...... and NOT Clymers!
Use the OEM ONLY!


Bob S

Click to expand...

OK thanks, I think we are on the same page now.
I have been using the Workshop Manual for the DP-D DP-D1 and DP-D2 exclusively. I've not even looked at the SELOC manual.
What you are referring to as the "transmission" is referred to in the manual as the upper gear head. That split ring keeper is indeed stress proof steel, and there are 4 revisions of the left hand thread nut of which I am using the current. All of the bearings in the transmission were replaced 2 seasons ago along with the gear set, and the new gear set seems to be wearing in with a correct contact pattern, so although I will again go through the setup procedure with a new pretensioning sleeve, I am assuming there are no issues there.
I looked at the A-B dimensions and they have to do with preload of the vertical shaft in the lower unit. That preload should be related to the vertical shaft bearing which should be independent of the amount of contact that the drive gear has with the driven gears, which is what the shim measurement I am addressing is concerned with. The shims that I am coming up with a negative value for, along with the shims for the driven gears will set the gear engagement and backlash values, which brings me back to my original concern as to why I come up with a negative value for the shim calculations. Especially since there were 0.5mm of shims in the drive which were put in there by a VP service when they replaced the lower gears 8 years ago.
I have been told that there may be a service bulletin that does away with this measurement, and starts with a standard shim package consisting of a 0.2mm paper shim with 2 - 0.05mm metal shims on each side as a starting point, and going to the gear contact and backlash measurements, but I have not been able to confirm this, or find any reference to that shim package. Do you have any knowledge of that bulletin?
At this point I am inclined to just put the original shims back in and proceed to the backlash and contact measurements since that is the final arbiter of what those shims should be, but it is disconcerting that the shop manual does not address this possibility.

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captbobs said:

OK thanks, I think we are on the same page now.
I have been using the Workshop Manual for the DP-D DP-D1 and DP-D2 exclusively. I've not even looked at the SELOC manual.
What you are referring to as the "transmission" is referred to in the manual as the upper gear head. That split ring keeper is indeed stress proof steel, and there are 4 revisions of the left hand thread nut of which I am using the current. All of the bearings in the transmission were replaced 2 seasons ago along with the gear set, and the new gear set seems to be wearing in with a correct contact pattern, so although I will again go through the setup procedure with a new pretensioning sleeve, I am assuming there are no issues there.
I looked at the A-B dimensions and they have to do with preload of the vertical shaft in the lower unit. That preload should be related to the vertical shaft bearing which should be independent of the amount of contact that the drive gear has with the driven gears, which is what the shim measurement I am addressing is concerned with. The shims that I am coming up with a negative value for, along with the shims for the driven gears will set the gear engagement and backlash values, which brings me back to my original concern as to why I come up with a negative value for the shim calculations. Especially since there were 0.5mm of shims in the drive which were put in there by a VP service when they replaced the lower gears 8 years ago.
I have been told that there may be a service bulletin that does away with this measurement, and starts with a standard shim package consisting of a 0.2mm paper shim with 2 - 0.05mm metal shims on each side as a starting point, and going to the gear contact and backlash measurements, but I have not been able to confirm this, or find any reference to that shim package. Do you have any knowledge of that bulletin?
At this point I am inclined to just put the original shims back in and proceed to the backlash and contact measurements since that is the final arbiter of what those shims should be, but it is disconcerting that the shop manual does not address this possibility.

I am sensing that you are not understanding the procedure, therefor I am not sure that I can be of any further help.

There are two initial set-ups;
one involving the lower gear unit set-up while using the factory tool to ensure downward force against the tapered roller bearing race.
a final A and B dimension that MUST be followed .... and again while using the factory tool. This must be done in order to KEEP the lower gear unit set-up as intended.


In order to do this correctly, one must understand the tapered roller bearing race's involvement in the positioning of, AND the downward force provided to the lower gear set's "drive" gear. (the race/roller cage checks the upward force keeping the gear contact correct!)

Too much shim value...... the race/roller cage will become damaged.
Not enough shim value....... the drive gear contact with the two driven gears will be incorrect, followed by severe gear set damage!

Click to expand...

Ricardo,

I do understand the relationship of the A - B dimension with regard to the vertical shaft. The preload pressure exerted by the shimming in the intermediate housing on the race of the tapered roller bearing prevents the drive gear from riding up, but on the other hand, if the drive is in reverse, the gear would tend to pull the shaft down, and the articulated ball bearing is there to provide the opposing force in the pretensioning setup to prevent shaft movement in the downward direction. The pretensioning is created between these two bearings. It is the shimming of that bearing that determines how far into the lower gear housing the drive gear extends, and consequently how much contact the gears make. So I go back to my original question? What do you do when the shop manual does not describe or even anticipate the possibility of a calculated negative value for those shims. That is why I said I see no other coarse but to put the original shims in and go through the end play, gear contact and pretensioning measurements listed in the manual.
I do not have the factory tool. I considered buying it, but I have the intermediate housing which while it would be clumsy, it can be used in place of the factory tool to set the A - B shimming on the race to do the initial setup. If I have to remove the race and change the shimming it can be done. I have done those calculations with the intermediate housing, and B = 8.13mm and A = 7.72mm. This gives me 0.40mm after the 0.01mm for preload is deducted.

Capt Bob S

Hi, folks
I'm new here and I have same problem.
According to OEM manual I have same problem with vertical shaft shimming as captbobs.
I recorded all shimms ticknesses and stampings at lower unit housing while disassembling.
For vertical shaft: 0.80mm shimms under vertical shaft bearing.
Pinion gear mark is +1 that is +0.01mm
H stamped is 99
According to OEM Manual:

H-nominally 277.00mm
H-stamped + 0.99mm

H=277.99mm

Pinion, nominally= 60.00mm
Pinion, stamped= +0.01mm
Pinion 60.01mm
Vertical shaft +217.75mm
277.76mm -this number must be larger than H and that is a reason why we must put shims under bearing, but in this(mine) case is not,
-277.99mm
-0.23mm minus value
But then, there were 0.80mm shims under vertical shaft. This was factory shimming.....
Only logical explanation is that nominally is 276.00 or 277.00. If I'm correct than OEM manuals from 285DP to DP-D are incorrect....
Please don't guess in your replays. In this thread we need Volvo Penta expert to give us answer.
Thanks

mklarend said:

Hi, folks
I'm new here and I have same problem.
According to OEM manual I have same problem with vertical shaft shimming as captbobs.
I recorded all shimms ticknesses and stampings at lower unit housing while disassembling.
For vertical shaft: 0.80mm shimms under vertical shaft bearing.
Pinion gear mark is +1 that is +0.01mm
H stamped is 99
According to OEM Manual:

H-nominally 277.00mm
H-stamped + 0.99mm

H=277.99mm

Pinion, nominally= 60.00mm
Pinion, stamped= +0.01mm
Pinion 60.01mm
Vertical shaft +217.75mm
277.76mm -this number must be larger than H and that is a reason why we must put shims under bearing, but in this(mine) case is not,
-277.99mm
-0.23mm minus value
But then, there were 0.80mm shims under vertical shaft. This was factory shimming.....
Only logical explanation is that nominally is 276.00 or 277.00. If I'm correct than OEM manuals from 285DP to DP-D are incorrect....
Please don't guess in your replays. In this thread we need Volvo Penta expert to give us answer.
Thanks

Click to expand...

if you start your own thread you will get more responses!

I would be interested if you get an expert answer; I never did. There are a couple of people on the Carolina Classic forum that encountered the same issue. I finally decided that I would use the shimming on the forward and reverse gears to adjust the centering and backlash and the vertical shaft to set the contact pattern on the gears. They are obviously not independent, but with this method I wound up with the original shim values on the vertical shaft so I am fairly confident of the results. It did take a few tries to get the correct numbers for backlash and the contact pattern looked good.

I guess if you want a expert answer you need to pay a expert!

All due respect ...........................

captbobs said:

I would be interested if you get an expert answer; I never did.
I think that it's fair to say that the answers and/or suggestions offered on this (or any) forum are very much influenced by how well or not well the information and questions are expressed in the thread's post #1.

The successful interpretation of the following answers and/or suggestions are typically a result of the OP's level of understanding and experience.

In other words, we do our best to make good and accurate suggestions, of which leaves the level of success up to the OP's ability to understand and to carry out the work scope.


There are a couple of people on the Carolina Classic forum that encountered the same issue. I finally decided that I would use the shimming on the forward and reverse gears to adjust the centering and backlash and the vertical shaft to set the contact pattern on the gears. They are obviously not independent, but with this method I wound up with the original shim values on the vertical shaft so I am fairly confident of the results. It did take a few tries to get the correct numbers for backlash and the contact pattern looked good.

From what I just now read, it sounds as though you were going through an entire Duo Prop lower unit "gear" set-up procedure.
If so, I did not interpret your thread title as to imply this!

Hopefully you have extensive Hypoid Gear set-up experience.
An AQ series Duo Prop gear set alone is approx $2k+ these days, not to mention the cost of the bearings.

Click to expand...

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