88950 Transmission Rebuild Question

[LegionPiper]

Thanks again guys,

I've been trolling old threads and came across this passage from Charles concerning the Transfer Case :
" Another trick we use is to apply a good bead of premium quality silicone to the nut flange or the flat washer just before the final installation of the shaft nut. When you torque the nut, that will press the sealant up into the splines. This will stop the oil from coming through the spline paths and leaking around the nut. Without the sealant, oil will find its way along the splines and leak regardless of how good the splines are. I also highly recommend using anearobic sealer on the redi-sleeve interior so any tiny imperfections in the yoke are sealed off as the sleeve is pressed on. Concerning sleeve depth, what we do is install the seal into position in its bore, then carefully slip the yoke onto the shaft without the sleeve; mark a reference on the yoke with a permanent marker in relation to the depth the sleeve should press to get the seal lip and sleeve in a good position, preferably in the middle area of the sleeve. Remove the yoke, seal and press the sleeve, then proceed with the final assembly. Extra time, of course, but this insures a proper, leak free installation that will last. "

Specific to this discussion around the transmission, I am assuming that the Redi-Sleeve will fit on the shaft before I place the Companion Flange back on ? Does it snug up against the main shaft bearing ?

Is a second Redi-Sleeve required on the Main Drive Gear Bearing Retainer too ?

Thanks

[MSeriesRebuild]

Thanks again guys,

I've been trolling old threads and came across this passage from Charles concerning the Transfer Case :
" Another trick we use is to apply a good bead of premium quality silicone to the nut flange or the flat washer just before the final installation of the shaft nut. When you torque the nut, that will press the sealant up into the splines. This will stop the oil from coming through the spline paths and leaking around the nut. Without the sealant, oil will find its way along the splines and leak regardless of how good the splines are. I also highly recommend using anearobic sealer on the redi-sleeve interior so any tiny imperfections in the yoke are sealed off as the sleeve is pressed on. Concerning sleeve depth, what we do is install the seal into position in its bore, then carefully slip the yoke onto the shaft without the sleeve; mark a reference on the yoke with a permanent marker in relation to the depth the sleeve should press to get the seal lip and sleeve in a good position, preferably in the middle area of the sleeve. Remove the yoke, seal and press the sleeve, then proceed with the final assembly. Extra time, of course, but this insures a proper, leak free installation that will last. "

Specific to this discussion around the transmission, I am assuming that the Redi-Sleeve will fit on the shaft before I place the Companion Flange back on ? Does it snug up against the main shaft bearing ?

Is a second Redi-Sleeve required on the Main Drive Gear Bearing Retainer too ?

Thanks

Redi-sleeve goes on the yoke seal mating surface, (companion flange is the military term for the yoke.) They give a new, smooth surface for the oil seal lip to ride on.

[LegionPiper]

Hey there Charles,

I eyeballed the parts last night on my bench and now totally understand what the purpose is for. ( Along with extra steps )
Thanks again for the direction.

Quick question regarding the Clutch-side Main Shaft - Drive, is there anything I should be aware of outside of the Main Drive Gear Bearing Retainer ??
What stops the Oil from seeping out the front end ?

[MSeriesRebuild]

Hey there Charles,

I eyeballed the parts last night on my bench and now totally understand what the purpose is for. ( Along with extra steps )
Thanks again for the direction.

Quick question regarding the Clutch-side Main Shaft - Drive, is there anything I should be aware of outside of the Main Drive Gear Bearing Retainer ??
What stops the Oil from seeping out the front end ?

Basically, nothing. We have done modifications to incorporate pilot shaft oil seals on numerous transmissions that had none originally. I have not seen a big deal with leakage via that route in these new process gear boxes. There is a plan in place, (machined onto the retainer bore to route residual oil back toward the main case) that the manufacturer deemed sufficient to curb oil escaping here. It does work better than you might expect. When I have seen issues is when something had gone wrong that caused the pilot shaft to wear against the interior surface of the retainer bore which screws up the tolerances, then original design is of course ruined. Let me say this, if it was to be a problem for you, (likely it won't) we can do some custom machining and install an oil seal. Bear in mind that if a seal is installed, a vent fitting will also have to be added to the top cover assembly, as the unit is designed originally to vent via that front bearing retainer since there is no oil seal.

[LegionPiper]

Hi folks,
another Rebuild Question.

How do you measure the gap between Synchronizer Outer Stop Ring and Third Speed Gear ?
https://drive.google.com/folderview?id= ... sp=sharing

** The Answer was in the Manual (There's a Military Acronym for that LOL)
Feeler gauges on both sides, after squeezing lightly together.

This is next to the Input Shaft
I have 1/4" gap between the Synchronizer outer stop rings and the gear beside them.
This distance should be no greater than .100 Inches, Mine is .112 inches.

Is there supposed to be springs in the Synchronizer assembly to keep pressure outwards, towards the gears ?
Nope, it floats
If I squeeze the Synch together, I can slide it back and forth between Third and Forth gears.


Is this normal ? Yes, within the Play Limitations in the Manual.
More on this in a later post. I have pulled it apart and measured all tolerances, with Interesting results.

[MSeriesRebuild]

Hi folks,
another Rebuild Question.

How do you measure the gap between Synchronizer Outer Stop Ring and Third Speed Gear ?
https://www.facebook.com/photo.php?fbid ... =3&theater

This is next to the Input Shaft
https://www.facebook.com/photo.php?fbid ... =3&theater

I have 1/4" gap between the Synchronizer outer stop rings and the gear beside them.
https://www.facebook.com/photo.php?fbid ... =3&theater

Is there supposed to be springs in the Synchronizer assembly to keep pressure outwards, towards the gears ?

If I squeeze the Synch together, I can slide it back and forth between Third and Forth gears.


Is this normal ?
If so, what is purpose / how do you measure between both sides ?

Not able to view your pictures, I'm getting a screen that tells me the link has expired.

Need a little more detail or you can email photos to mseriesrebuild@windstream.net Main thing I need to know; is the synchronizer gear that is splined on the front end of the main shaft moving fore and aft? Or are you referring to the assembly sliding on that stationary gear? The synchro has to float a given amount in order to function correctly.

[LegionPiper]

Hi Folks,

The following manual explains the 88950 Transmission, starting at page 141 ( Chapter 7 ).
TM 9-8031-2 /T 019-75—A-100
Page 142 describes this as the New Process Model 88950.
I assumed it was a variant of the NP 420 and often referred to is as such, but was totally wrong !

Another HUGE lesson, the 88950 is really a gear box, who moonlights as a transmission.
Why is that important ??? Because it means you have to be really careful if you ask for "Transmission Assembly Lube "
I picked up a tub, which I guess is for Automatic transmissions. It comes as a greasy paste.
So, I cleaned it up and picked up a tube of Engine Assembly Lube which looks more like oil.
There's no way I want to wreck all of my hard work on this puppy.

Once I get the parts together to get her back to Spec, I'll post an update to this Thread with more pics.
( I updated the link in the previous post, which was not working, can someone please IM me if it still doesn't work ? )

Thanks to Charles for all of your coaching and help.

[LegionPiper]

Question on the Main Shaft Pilot Bearing Spacer.

Has anyone modified this part to help adjust the Synchro Assembly end-play ?
( Along with shims on the shaft to compensate ?

Second Question, parts like the Shims, Gear Locating washers are no longer available at places like Mid West.
Any other leads ?

Thanks

[MSeriesRebuild]

Question on the Main Shaft Pilot Bearing Spacer.

Has anyone modified this part to help adjust the Synchro Assembly end-play ?
( Along with shims on the shaft to compensate ?

Second Question, parts like the Shims, Gear Locating washers are no longer available at places like Mid West.
Any other leads ?

Thanks

The answer to the gear locating washers is simple, custom make them per the needed spec as we discussed via email. Even if you had original NOS, not likely you would come up with the right combination for the best set up. We can custom punch shims, we made a die for that many years ago.

[LegionPiper]

Thanks Charles

I thought I bring the technical questions back to the Forum such that we can share with all.

I'm glad to know I am down the right path by modifying the Ring. ( Pilot bearing Spacer )

GREAT to know you have a Shim die.

I am going to reach out once I make my adjustments this weekend.

[MSeriesRebuild]

Thanks Charles

I thought I bring the technical questions back to the Forum such that we can share with all.

I'm glad to know I am down the right path by modifying the Ring. ( Pilot bearing Spacer )

GREAT to know you have a Shim die.

I am going to reach out once I make my adjustments this weekend.

You are losing me on the pilot bearing spacer.

[LegionPiper]

Hi Charles,
I observed that when I assembled the shafts without the " Main Shaft Pilot Bearing Spacer ", I closed the space that I needed to reduce the gap between Outer Synchro Ring and 3rd speed gear.

The extra space now appears on the output side of the Main Shaft, next to the existing shims.
The main shaft is still tight and tolerances are good with respect to gears, Thrust washers, etc.
( In my email to you, I mistook the Snap Ring with the Bearing Spacer's function )

Therefore I am assuming that I can now reduce the thickness of the Pilot Bearing Spacer to close my gap ( That "ring" sitting at the top of the main shaft ) & add the same amount of Shim filler to the output end of the shaft.

I'm really bad at describing things, so hopefully this makes sense ?

[MSeriesRebuild]

Hi Charles,
I observed that when I assembled the shafts without the " Main Shaft Pilot Bearing Spacer ", I closed the space that I needed to reduce the gap between Outer Synchro Ring and 3rd speed gear.

The extra space now appears on the output side of the Main Shaft, next to the existing shims.
The main shaft is still tight and tolerances are good with respect to gears, Thrust washers, etc.
( In my email to you, I mistook the Snap Ring with the Bearing Spacer's function )

Therefore I am assuming that I can now reduce the thickness of the Pilot Bearing Spacer to close my gap ( That "ring" sitting at the top of the main shaft ) & add the same amount of Shim filler to the output end of the shaft.

I'm really bad at describing things, so hopefully this makes sense ?

Maybe nothing more than a terminology difference, but it isn't clicking with me what you are referring to as the pilot bearing spacer.

[LegionPiper]

HI there,
attaching a cut-away picture.
I am referring to the wee ring labelled "BB" in the diagram.

This is on the Input Shaft facing-side of the Main Shaft.
Once I realized that this is setting the distance between 3rd and 4th gear, I figured I can now change that gap !

Am I on the right path, or is this going to cause me grief down the road ?

[MSeriesRebuild]

HI there,
attaching a cut-away picture.
I am referring to the wee ring labelled "BB" in the diagram.

This is on the Input Shaft facing-side of the Main Shaft.
Once I realized that this is setting the distance between 3rd and 4th gear, I figured I can now change that gap !

Am I on the right path, or is this going to cause me grief down the road ?

Issue here will be different for each unit, if the main shaft is forced too far forward, it will lock it; be very mindful of this. Also pay close attention to shifting the main shaft forward or backward too much, in relation to getting the gears out of sync with the mating gears on the lower counter shaft. While all we have discussed up to now is extremely important in building the best running trans, you have to pay attention to everything in the big picture as well so all ends up within the correct realm of balance. Remember that when you torque the rear yoke nut on the back, the main shaft will be pulled to the rear somewhat.