ZF5 (S5-47) Transmission Rebuild

In the following, I will show you how to tear down and rebuild your ZF5 transmission with new syncronizer rings,

tapered roller bearings, caged gear bearings, and oil seals.

First, drain the transmission. Then, remove the shift tower housing from the transmission case. Then, punch a hole

in and pry out the three cup plugs that hold the shift rail detent springs in the case. Remove the springs and you can

leave the detents in the bores.


Next, stand the transmission up on its tail end and drive the two dowel pins between the rear housing and main case

towards the rear of the transmission.



Then, remove the reverse gear idler shaft bolts from the case.


Then, remove all the bolts holding the rear housing to the front case. Carefully separate and slide the main case up

and off of the rear housing. Be careful not to get the main case stuck on the shift rails.


Remove the main shift rail.


Pull the reverse gear idler shaft out of the reverse idler gear.


Take out the reverse idler gear, making sure to catch the two caged bearings.


Remove the three socket head bolts holding the shift rail plate to the rear housing.


Strap the shift rails, countershaft, and main shaft together with some ratchet straps in preparation for removal from

rear case half.


Lift out the above strapped bundle.


Lay your parts out to work.


Pull the input shaft off of the main shaft and slide the syncronizer collar off the 3-4 syncronizer body. Catch the

sliding detents and springs.


Inspect the 4th gear syncronizer ring and input shaft/4th gear syncronizer cone for abnormal wear.

Now, at this point the rebuild manual calls for some special bearing puller collets that I didn't have and didn't want

to purchase. We're replacing the bearings anyways right? First bearing to be removed is the large tapered roller

bearing on the input shaft. I cut the cage off and then used a generic bearing puller.



Next, to remove the tapered roller bearings from the countershaft. First I cut the cage off.


Then, hook up the generic bearing puller.



Next bearing to remove is the input shaft pocket bearing from the main shaft. I was able to get the generic bearing

puller behind this bearing and therefore did not have to cut the cage off and pull from the front edge.


The final tapered roller bearing to remove is the rear mainshaft bearing. You must first remove a large snap ring

(4WD style has this snap ring, not sure about 2WD models).



Once this bearing is off, you can pull 5th gear off the mainshaft.


Follow that up with removing the 5th-reverse syncro sliding ring and be sure to catch the three sliding detents and

springs that will come out.

I then moved to the front of the mainshaft and removed the large snap ring that was behind the input shaft pocket

bearing and that ensures the 3-4 syncronizer body doesn't move on the shaft.


Now you're ready to pull your first syncronizer body! For this step, it is strongly recommended to purchase the

required service tools. YOu will need puller collets; T87T-7025-NH, T87T-7025-MH. You will also need collet

retaining ring T87T-7025-OH. Use collet NH to setup on the 3-4 syncronizer body and pull with a standard three jaw

puller.



Now to get ready to pull the 1-2 syncronizer body off the main shaft, slide it all the way towards 2nd gear.


Set up collet MH on the actual sliding sleeve of the syncronizer assembly as such.

Start pulling 2nd gear and the 3rd gear bearing race and thrust washer off the mainshaft.


Make note of the direction the 1-2 syncro sliding sleve you just pulled off was facing. Tapered end facing 1st gear.


Next remove the large snap ring holding the 1-2 syncronizer body onto the main shaft.


Then for some reason I flipped back around to the rear of the main shaft and started pulling the 5-reverse syncronizer

body with the collets and collet retainer.


Lastly you can just pull directly on 1st gear towards the front of the mainshaft to get the 1-2 syncronizer body off

the shaft.


All broken down.


Now we must remove the bearing races from the front and rear case halves since we are replacing all the tapered roller

bearings. Its no good to re-use old races with new rollers. To do this requires a blind hole bearing puller. I found

that OTC 6542 works well and is cheap.


Set up your puller and slide hammer and such and remove all the races in the case halves.



Make sure not to lose the race spacers from the two races in the front case half.



This concludes the tear down of the transmission.

Go and order your rebuild kit and make sure it includes new syncronizer rings, tapered roller bearings, caged gear

bearings, and seals. Be sure to order the kit for your revision of ZF5 (either S5-42 or S5-47).

To rebuild the unit, lay out all your old and new parts.



First, clamp the main shaft in a soft jaw vice with the output end facing up. Put the reverse gear bearing on the

main shaft and then drop the reverse gear onto the main shaft.


Put your new reverse syncronize ring on the reverse gear.


Put the 5-reverse syncronizer body into the oven at 320 for 20 minutes.


Once its good and hot, grab it and drop it onto the main shaft making sure it seats all the way down towards reverse

gear.


Note that this syncronizer body must be installed with deeper hub facing down (toward the input side of main shaft).


Go ahead and start heating up the rear mainshaft tapered roller bearing.


Reinstall the large snap ring to ensure the 5-reverse syncronizer body can't move on the shaft.


Install the syncronizer sliding ring and the detents and springs onto the 5-reverse syncronizer body.


Put the new 5th gear syncronizer ring onto the 5-reverse syncronizer body making sure the teeth line up in the sliding

ring.


Install the 5th gear roller bearings onto the main shaft.


Drop 5th gear onto the shaft and then grab the hot tapered bearing out of the oven and drop it onto the mainshaft.

Tap it down to make sure its seated.


Once the bearing is cool, reinstall the snap ring you removed during dissassembly.
'

Flip the mainshaft over in the vice so the input end is pointing up. Get your new 1st gear roller bearing and put it

on the mainshaft. Then put first gear on the mainshaft.

Get the new 1st gear syncronizer ring and put it on the taper of first gear as shown.


Heat up the 1-2 synronizer body and drop it onto the main shaft.


Reinstall the large snap ring to ensure the 1-2 syncronizer body can't move on the mainshaft.


Next install the 1-2 syncronizer sliding ring and the three detents and springs onto the 1-2 syncronizer body.

Remember the tapered face goes towards 1st gear!

Get the new second gear roller bearing and install it on the mainshaft as well as second gear.


Next, put the 3rd gear bearing race/spacer and thrust washer in the oven to heat. Once they are hot, drop them on the

mainshaft after second gear. Tap down to make sure both are seated.


Once these have cooled, install the new 3rd gear bearing and third gear.


Put the new 3rd gear syncronizer ring onto 3rd gear taper.


Heat up the 3-4 syncronizer body and drop it onto the mainshaft next.


Reinstall the snap ring to hold the 3-4 syncronizer body onto the main shaft.


Inspec the input pocket bearing race and oil scoop in the back of the input shaft for damage. A new oil scoop ring

came with my rebuild kit but mine was in good shape so I didn't replace.


Heat the input shaft pocket bearing in the oven and drop it onto the main shaft.


Main shaft is now rebuilt.


No pictures, but heat up the two tapered roller bearings that go on the countershaft and drop them on.

Now install all the bearing races into the front and rear case halves. Do not install the bearing shims under the

races in the front case half at this time!



Mesh the mainshaft and countershaft together and bind them up with a ratchet strap.

Set up the mainshaft and countershaft such that the end is hanging off your workbench. Then slide the rear case half

over the main and countershafts.



Carefully grab it all and stand it up.


Make sure and space the case up a bit as the mainshaft output extends slightly past the end of the case.


Grab your new reverse idler gear shaft bearings and install them along with the reverse gear idle shaft and reverse

gear idler bearing.


Take the front case half and slide it down over the main and countershaft.


Put some bolts in to hold the case halves together and then flip the works over.


Now we check the bearing clearance to determine the shims we need to set the proper bearing preload. Tapered bearing

preload is very important with this transmission since the case material (aluminum) is different from the main and

countershaft material(steel). These two materials will expand at different rates when in use and hot and this could

lead to excessive clearance in the tapered roller bearings.

To check the mainshaft tapered roller bearing clearance, set up the dial indicator on the output end of the mainshaft.


Pry up on the end of the input shaft. Make note of the clearance.


To check the bearing clearance on the countershaft, I used a magnetic level on the 4th gear driven gear on the

countershaft and set up the dial indicator to measure off of it.


Then pry up on the 4th gear driven gear of the countershaft from the other pto hole in the front case half. Note the

clearance from the dial indicator.


Once you have these clearances with no shims installed you can calculate the required shim thickness. For the

countershaft you take the clearance and add between 0.00079"-0.00434" to this number and that is the required shim

thickness you need to add under the front race on the countershaft tapered bearing. For the main shaft, you take the

recorded clearance and subtract the thickness of the new oil baffle. Then add 0.00079"-0.00434" to this number and

you have the required thickness of the main shaft front tapered bearing shim. I was lucky and the shims I removed

from the transmission would work to set proper preload after rebuilding.

Turn the transmission back over and remove the front case half. Set up your blind bearing race puller and slide

hammer.


Pull the two bearing races from the front case half and then install the shims and hammer the races back in the front

case half.


You will have to pull the main and countershafts out of the rear case half to install the shift rails and collars. It

will be a pain to get it all back in the rear case half but it can be done with no special tools.


Reinstall the socket head screws to the shift rail plate in the rear case half.

Reinstall the reverse idler gear and shaft. Install the lower bolt through the rear case half to hold the idler shaft in place.


Don't forget the magnet.


Install the main shift rail.


Pick up some anaerobic sealant from the parts store and lay out a nice bead on the flange of the rear case half.



Drop the front case half back onto the rear case half and start the bolts. Take the bolts finger tight and then drive the two dowels back in aligning the case halves. Tighten the bolts holding the front and rear case halves to 17 ft-lb.


Install the other reverse gear idler shaft bolt.


Before the sealant cures, bolt on the shift tower and stub and run through the gears to make sure there were no

mistakes.


Install the new input shaft oil seal. The small block version of the ZF5 is constructed such that the input shaft oil

seal can be replaced without tearing down the trans. Just tap it in with a big socket. There is no positive stop in

the bore but the manual just said to drive it in so the end is flush with the case.



Turn the transmission over and drive in the output shaft oil seal with a piece of pipe or PVC.


Put the shift rail detent springs back in the bores and install new cup plugs. Your done!


This is the manual I used to perform the work.

http://www.zf.com/na/content/media/...rtfolio/lcv/S5-42_47__47M_Service_manual_.pdf

Wow! That's a great write up and should always be in the Tech Section!

Great work man.

Heath

By the way. I love the XR400. I had one from '97-'01. I loved that bike and wish I still had it rather than my CRF450.

Heath

Great write up, details, etc.

Change your avatar to "ZF Ninja"

Thank you for this wonderful write up, I too agree...completely needs to be in the TECH section.

Just so I'm 100% clear,

This S47 is a SMALL block version Correct? I did not notice a clutch fork opening or a Slave cyl tab/mount.

Thanks for an incredibly detailed write up.

My only issue is following the clearance check math I'm unclear on it. I suppose when/if I did this it would likely become more clear...I hope!

Al

Beverage of your choice, on me, any time !!!

Great writeup and great pictures with comments. I used to do tech writing so I understand the effort needed to pull this all together.
My respect and thanks for doing it all so well.

Grant

Thanks all for the kind words. Hopefully folks can get some use out of this and be confident to rebuild their transmission.

riotwarrior said:

Just so I'm 100% clear,

This S47 is a SMALL block version Correct? I did not notice a clutch fork opening or a Slave cyl tab/mount.

Click to expand...

Yes correct, this is a small block version of the ZF. The small block version uses an internal slave. In the picture of the input shaft seal install, you can see the two bolts that would hold the slave concentric over the input shaft. In the last picture, you can see the two holes in the drivers side bellhousing, the top being for the slave bleeder and the bottom for the hydraulic line to the internal slave. Also, I should add, regardless of small block, big block, or diesel the internal wear parts are identical between the transmission (so long as you don't cross revisions, S5-42 to S5-47).

riotwarrior said:

My only issue is following the clearance check math I'm unclear on it. I suppose when/if I did this it would likely become more clear...I hope!
Al

Click to expand...

So the best thing to do would be to glance at the link in the bottom of the last post with pictures and it describes the shimming procedure. In fewer words, you have to set the tapered main and countershaft bearings up with some preload on them. Much like you have to adjust spindle nuts to preload wheel bearings, else they'll toast themselves in short order. What I was trying to explain that you have to first determine the clearance between the bearings and races in an unshimmed state, then you must take this number and add the specified .00079-.00434" preload to determine the required shim thickness. Its as simple as that for the counter shaft, for the mainshaft you must take this final number and then subtract the thickness of the front oil dam that goes below the front race in the case.

Long story short...best to just consult the linked manual from ZF on the bearing preload setup. That is probably the most important part of the process. A perfect rebuilt could be ruined by loose bearings. That is actually one of the main reasons I rebuilt this one. I could grab the input shaft and wiggle it around. Clearly the bearings were worn.