1995 Prostar. Gearbox problem.

[eurosysytem0]

Update. Hurth ZF: Transmission oil changed & Transmission Oil filter cleaned. When engine running and in neutral looking into transmission filler hole, Oil is flat calm.

Place the throttle lever "in gear", lever moves (forward and reverse on Transmission housing). Confirmed the transmission shaft is turning when transmission lever is put into gear.

The oil in transmission remains flat calm (ie. nothing inside transmission is generating any oil ripples) when gear is selected. Finally its worth highlighting that the return pipe (from the top of the oil cooler was and remains empty.

Am I right to assume the only solution is to take out transmission and undertake overhaul?

What is the likely failure within the transmission?

Any quick fixes to try?

[eurosysytem0]

Bump. Any more help out there?

[waterlogged882]

Bump. Any more help out there?

No help here.

However your assessment is narrowing down to one of just a few choices. My suspicion is the internal pump has gone south. But that is merely speculation of calm fluid where it should have ripples from movement. I am beginning to think a rebuild is in order. While you are there, replace the damper plate. No better time.

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[EricB]

I agree...time to pull it out. The only other check would be to do a pressure check on the transmission when running (I assume this can be done, but I have not done a check. It would be in the Hurth Service Manual). Once the trans is out, you can visually inspect the dampener plate, but should be replaced anyway.

[eurosysytem0]

Update: Reminder
1998 Sammy Duval Prostar. Chevy Corvette Engine Hurth HSW450 D Transmission
Boat all working when laid up. Not used for 11 months.
Purchased by one friend from another. Boat been on our lake for 15 years.

Engine Start - Perfect.

When placed in gear (either forward or reverse) no output to props shaft,
Oil (clear) changed and topped up to right level- No change.
Disconnect output pipe to Oil Cooler. Pipe empty no flow.
Removed oil filler cap.to see oil. Engine running, gear selected absolutely No ripples or oil movement in oil.
Removed transmission, split casing. Every component looked perfect (new)
Reassembled transmission and took to UK Hurth Marine Transmission specialists Over-haulers/repairers.
Paid equivalent of $550 for tests and diagnostics,
Hurth Agent states Transmission fully serviceable. !!!

Refit transmission. No change. With engine running. Transmission in Forward/reverse/ neutral No output to prop shaft.
Remove transmission and paint spot transmission spline shaft Refit turn engine splined shaft not moved.
Start measurements
Photo 1 Pressure plate

Photo 2 Measurement from face of pressure plate spline to mating face of Bell Housing 60mm

Photo 3. Measurement of splined transmission shaft from corresponding transmission/bellhousing case mating face to shaft end. 60mm!!


Bottom line: With Transmission fully located against Bell Housing the SHAFT is not reaching Pressure Plate splined bearing. So Engine turns but transmission NOT coupled to pressure plate.

So what are the possibilities for transmission shaft and pressure plate not reaching each other?

1. Pressure plate has moved away from transmission shaft. Was it domed and is now flat? Unlikely? No distortion etc see photo 1.

2. Transmission shaft has retracted into transmission. (see Photo 2) All checks and Hurth checks say it serviceable and there is not a micron of in out movement in shaft.

3. Was there an splined male //female adapter that went between transmission shaft and pressure plate splined bearing (which was dropped/lost when gearbox removed) which effectively extended the transmission shaft 20mm to insert with Pressure plate. Bearing in mind the shaft and bearing engagement should be circa 20mm length of splines. Search for an "adapter/connector carried out nothing found.
Should there be an adapter/connector?

In desperation we removed bell housing and turned pressure plate round so that the internal engine face was facing outwards to transmission. Now the shaft marginally ngaged with pressure plate circa 5mm.

However, now when engine turned the transmission turned !!!!

So the question for all the experienced talented Team Talk members is.

What the hell has happened to a serviceable boat that has resulted in the transmission shaft not engaging with pressure plate Circa 20mm too short

How do we fix it?

Please help we are going crazy!!

Ian

[waterlogged882]

Commonly known as the ZF 45C model transmission. I ask hesitantly, do you have the service manual for dimensions, diagrams, etc.? I suspect yes.

Is the transmission clocked properly (although that has nothing to do with the dimensional dilemma)?

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[eurosysytem0]

Waterlogged882. Thanks for your reply.
We have copy of similar transmission repair manual but not the 45C. The manuals that we have don’t specify the length of protruding input shaft to reach installed damper plate. Nor do we have anything that defines measurement from plate splined bearing face to Bellhousing to transmission mating face as shown in my photos. The transmission is correctly clocked.

If anyone out there has a schematic for the 45C installed input shaft dimensions it would be gratefully received.

Also the part number / Picture of the correct damper plate for Corvette engine and Hurth ZF 45C transmission.
Thanks again
Ian

[waterlogged882]

Waterlogged882. Thanks for your reply.
We have copy of similar transmission repair manual but not the 45C. The manuals that we have don’t specify the length of protruding input shaft to reach installed damper plate. Nor do we have anything that defines measurement from plate splined bearing face to Bellhousing to transmission mating face as shown in my photos. The transmission is correctly clocked.

If anyone out there has a schematic for the 45C installed input shaft dimensions it would be gratefully received.

Also the part number / Picture of the correct damper plate for Corvette engine and Hurth ZF 45C transmission.
Thanks again
Ian

From a 45C manual I have. Hope this helps. The stingies here will not allow a PDF file more than 1.9 MB, thus I cannot upload to post. I think they cannot figure out how to up the file limit size in the control panel. lol

Your flywheel can mount only in one specific bolt alignment pattern. One bolt is off by a tiny bit except for the one specific position. Then the damper onto that. The springs (or if covered) are on the visible side of the flywheel looking at the rear of the engine. I know you have wrestled that thing in every possible position, but I think the spline shaft in the transmission you show, relative to this manual specification, is correct. Sure looks it to me.

I have a nice color manual with clear text instead of the crappy black and white one floating around. Message me your email and I'll shoot it across the pond to you. This (below) particular photo did not come from that manual. I'll send a few different versions.

.

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[waterlogged882]

Here is the Sach's damper for the Chevrolet small block, which I think the LT1 is just that (350 c.i.). The triangular configuration may hang over the flywheel ring gears by about 1/4" therefore it is not uncommon to have to trim the ears to clear the teeth. There is a lighter duty round damper, which I think is just a good in functionality and service.

No part number per se' because I plagiarized this from an internet site for example (specific). I can confirm this is for the Chevrolet small block 350 marine application.

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[eurosysytem0]

Here is the Sach's damper for the Chevrolet small block, which I think the LT1 is just that (350 c.i.). The triangular configuration may hang over the flywheel ring gears by about 1/4" therefore it is not uncommon to have to trim the ears to clear the teeth. There is a lighter duty round damper, which I think is just a good in functionality and service.

No part number per se' because I plagiarized this from an internet site for example (specific). I can confirm this is for the Chevrolet small block 350 marine application.

.

Hi everyone.

I am now convinced that the boat has the wrong damper plate fitted. How it worked previously is beyond me!
You will notice that the picture provided by watterlogged has the bearing face well "proud "of the plate face. Thereby moving it towards the transmission shaft, thereby facilitating MORE shaft into bearing interface. You will see that my photo of current plate installed the bearing face is "flush" with the plate.

See also below

This is SKIDIMS recommendation for Corvette/Hurth 450D configuration. This again move the bearing interface even closer to the transmission shaft. This is apparently for higher load usage and is three times the price of the Sachs plate. Skidim sell both.

needless to say, as usual, the shipping and import duty ramps up the price for us Brits.

All help appreciated.
Ian

[RDahler]

After looking at the photo of your Damper Plate threw the hole in the back of the bell housing some one has installed the Plate backwards. The elevated part must be installed out so the transmission will mate up. It may have caught on the end of the spline and worked for a short time installed like it is. Just flip it over and you should be good to go.

[Bouyhead]

Good eye.

[eurosysytem0]

After looking at the photo of your Damper Plate threw the hole in the back of the bell housing some one has installed the Plate backwards. The elevated part must be installed out so the transmission will mate up. It may have caught on the end of the spline and worked for a short time installed like it is. Just flip it over and you should be good to go.

RDahler: Absolutely spot on! Well observed. We turned it round and it went fro zero engagement to 9mm engagement and the transmission now turns when we turn the engine. It still means that another 10mm- ish of the transmission shaft is not engaged though.We are trying to source the Sachs pressure plate in the UK to change it anyway now transmission is out. So far no luck!

Mastercraft UK have no pressure plates for Indmar engines!!! Other sources also failing.

have found this on ebay. I think its the right one? Views?

https://www.ebay.co.uk/itm/281784488...3ABFBMztv_1Mxg

[waterlogged882]

Update: ...we removed bell housing and turned pressure plate round so that the internal engine face was facing outwards to transmission.
Ian

What happened here the first time you turned it around?

What changed on the second repeat step?

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[eurosysytem0]

What happened here the first time you turned it around?

What changed on the second repeat step?

.

Hi Waterlogged. The first post was an estimate based on visual and transmission pushed in but not tightened.
2nd time we spread grease on shaft spines, fitted transmission, tightened securing bolts.

Released transmission, withdrew transmission and measured grease displacement on shaft..
Regards
ian