Trs rebuilding 101

[Chris]

i just downloaded that trs manual & oh boy, i dont even know were to start w/ my drives. lol. :

What Mel Riggs charges to do the drives right is a fraction of what doing them yourself incorrectly will cost you.

 

[Toasty]

what does riggs marine get for a trs rebuild? (depending upon what is broken) what where your exps?

C

 

[FULL FORCE]

The upper units on the TRS drive are very beefy with large gears. You can easily pull the top and back caps to check the gears for pitting and wear. If they look good and the fluid was clean I would concentrate on the lowers, because the lowers are the weak link with TRS.

Use the best lower housings you have, with the most/thickest material around the bullitt. Make sure the lower gears you use have no pitting(new would be best). All the bearings are available from local bearing distributors except for one vert shaft roller bearing(merc only). Shims are also available from merc. It helps to have a parts catalog in addition to the manual.

Two important things to know about with the TRS lower: 1) The lower verticle shaft roller bearings are preloaded with shims that are located in the upper housing, and setting that preload properly is critical to survival. 2) The right rotation drive puts the lower drive gear(prop shaft gear) on the back side of the pinion gear, making the rt drive the weaker of the two (since the gear is not supported as well, being in the thinner part of the bullitt). Hard shimming the right lower instead of using the crush ring helps eliminate bullitt flexing, adding to gear life. All the stock parts in a TRS are bigger in comparison to the same related parts in a Bravo, so in good condition with proper setup, they can handle 650/700hp in a twin engine application. With 600hp, I would expect the lower gears to last over 200hrs(400+ on the upper gears).

I ran TRS's with 550/600hp on a 311 Formula for over 500hrs(hard), and the only issues I had were wearing out the lower gears, and cracking a freshly rebuilt lower housing at the bearing carrier because the housing was thin(wore out) around the rear of the bullitt. A stock 1" TRS prop shaft is beefier then a 1" Bravo shaft(non XR), so prop shaft failure hopefully wont be an issue.

Good luck, LE

Good thing I have a good friend that can do mine when needed!!:03:

 

[J-Bonz]

The upper units on the TRS drive are very beefy with large gears. You can easily pull the top and back caps to check the gears for pitting and wear. If they look good and the fluid was clean I would concentrate on the lowers, because the lowers are the weak link with TRS.

Use the best lower housings you have, with the most/thickest material around the bullitt. Make sure the lower gears you use have no pitting(new would be best). All the bearings are available from local bearing distributors except for one vert shaft roller bearing(merc only). Shims are also available from merc. It helps to have a parts catalog in addition to the manual.

Two important things to know about with the TRS lower: 1) The lower verticle shaft roller bearings are preloaded with shims that are located in the upper housing, and setting that preload properly is critical to survival. 2) The right rotation drive puts the lower drive gear(prop shaft gear) on the back side of the pinion gear, making the rt drive the weaker of the two (since the gear is not supported as well, being in the thinner part of the bullitt). Hard shimming the right lower instead of using the crush ring helps eliminate bullitt flexing, adding to gear life. All the stock parts in a TRS are bigger in comparison to the same related parts in a Bravo, so in good condition with proper setup, they can handle 650/700hp in a twin engine application. With 600hp, I would expect the lower gears to last over 200hrs(400+ on the upper gears).

I ran TRS's with 550/600hp on a 311 Formula for over 500hrs(hard), and the only issues I had were wearing out the lower gears, and cracking a freshly rebuilt lower housing at the bearing carrier because the housing was thin(wore out) around the rear of the bullitt. A stock 1" TRS prop shaft is beefier then a 1" Bravo shaft(non XR), so prop shaft failure hopefully wont be an issue.

Good luck, LE

Good explination Scott

 

[mbam]

I can only talk about the Merc props, as that's all we sell. In general a B1 prop (4 blade, come in even pitch numbers) will turn the same RPM as a Mirage Plus in the next inch size (22" B1 = 23" Mirage plus for example). A Revolution 4 (which is a great prop btw) comes in odd pitches and will pull about 300 RPM less than the Mirage in the same pitch. And I absolutely agree that a 4 blade on a TRS with big power is asking for trouble.

 

[FULL FORCE]

if a 3 blade is at a pitch that will bite, and a 4 blade is at a pitch that will bite, lets say they both have the same slip rate, wouldn't they both be just as hard on the drive?

I am not sure that makes sense, hard to explain what i mean.

I have a friend running 4 blade 28P on a TRS with a ScarabIII and 600 hp, never hurt a drive.

 

[MOBILEMERCMAN]

Well, the operator will have a big influence on longevity. I don't know how to explain the prop thing.

I remember some customers going thru drives like popcorn in the '90's. 4 blades just seem to break more often. A Blower motor making 600 some odd hps breaks more than a 600 hp non blower. The bigger the boat the more they break. If it can go 90 mph your on borrowed time. IMO

It is possible to get them to live. But you can't beat on them.

 

[FULL FORCE]

Well, the operator will have a big influence on longevity. I don't know how to explain the prop thing.

I remember some customers going thru drives like popcorn in the '90's. 4 blades just seem to break more often. A Blower motor making 600 some odd hps breaks more than a 600 hp non blower. The bigger the boat the more they break. If it can go 90 mph your on borrowed time. IMO

It is possible to get them to live. But you can't beat on them.

He had blowers for a few yrs making a little more hp, basically like you said driving and boat ,makes some difference, I just remember comparing my TRS parts to Bravo inners... I'll keep my TRS's.....

 

[MOBILEMERCMAN]

I always like the way a trs boat rode over a bravo boat. Just like now I like the way a #6 boat rides over a bravo boat.

But that is just a personal preference.

 

[FULL FORCE]

I always like the way a trs boat rode over a bravo boat. Just like now I like the way a #6 boat rides over a bravo boat.

But that is just a personal preference.

I agree, I think my boat rides great, even for a Baja! Alot of people told me to go Bravo when i did the transom, I did not want to, I like my transmissions and the boat has a good center of gravity, helps the ride I am told. Trannies are nice when docking...

 

[LAKE EFFECT]

Most TRS boats were setup from the factory with deep X-dimensions, so a good 3 blade should give you the best overall performance. When the drives are raised during a re-rig, a 4 blade might pick up performance.

The TRS came out in 1974, and does have big components. I dont know what kind of technology/metallurgy is in the shafts and gears(old school I'm sure). Just like a Bravo with bigger power, the lower gears become a weak link because their size is limited by the bullitt diameter. I believe the Bravo gears do have a better heat treating process, plus the TRS gears are helicut, still making the TRS lower gears the weakest link. If you plan on running any power thru a TRS, I would inspect the gears every season or around every 100hrs. I have heard about 4 blades tearing up TRS's, but dont know what there breaking, worn lower gears maybe?

Overall the TRS is a good drive with big parts and a smooth shifting transmission. As long as you keep an eye on the weak links and maybe surplus some extra parts, they can be very dependable to run. No worse then a Bravo, believe me..

LE

 

[Geronimo36]

I still have some odd's and ends left over from my TRS if anyone needs any shafts and even a lower case. The lower case isn't in the best shape but ya never know...

I found the uppers to be pretty stout and never broke one but the lowers needed help.... I stopped using the crush collers after the second rebuild and that seemed to help a lot! I also found that when replacing the gear sets in the lower I rarely had to re-set pinion depth and they came within tolerance every time so go figure....

 

[Holy Smokes]

So refreshing to see some positive experiences with TRS drives. I love mine and have never missed that tell-tale "CLUNK" of a bravo going into gear.

I tried some 21P Rev4's this season to replace my 23P Mirage's and was not totally impressed by the performance. They helped getting on plane slightly faster, but could only turn them to 4500 rpm WOT. I should be closer to 5000. From that and from what others above had said above; the Rev4's are gone.

 

[Chris]

The 4-blade thing is like putting slicks on your car. If you drop the clutch with street tires (3-blade props), they spin, relieveing some of the instantaneous shock loads. A 4blade is more like slicks- instant bite.

 

[BDiggity]

I love mine and have never missed that tell-tale "CLUNK" of a bravo going into gear.

Yes i couldnt believe the first time i shifted & it was smooth as butter. I was thinking where is the clunk??

The drives were checked over about 3 years ago. I only put about 5 hrs on it last summer & since i hate breaking things im always nursing it along. I would like to have some silver Konrads on the back but want too many other things first. Next summer i will test out different props & see how the boat likes them. I just need to figure out where i was taking on water & see if indeed i was leaking fluid. Once that is fixed, i think they will continue to hold up. I have to get the "wifes projects" done first before moving on to the performance upgrades.

 

[scarrab30]

I rebuild my own TRS. I run 26quad 4x props and spin them at 58-6000 on a 30ft boat. Ive never broken one yet. I run 540's. There is plenty video of how we abuse the sled. Brian

 

[Geronimo36]

I still have some odd's and ends left over from my TRS if anyone needs any shafts and even a lower case. The lower case isn't in the best shape but ya never know...

Here's some of the TRS stuff I have laying around... I sold the propshaft and have the lower vertical shaft, input shaft, pinion shafts still available.

I have no need for it, maybe someone else will and I'm too lazy to put it up on ebay. :seeya:

 

[Clustergear]

TRS Drives

I have been running a TRS on my Avanti for 25 years. I have been rebuilding drives as a side job for 30 years. only problems I have had with TRS drives is when I and some of my freinds were using an adaptor on prop shaft to run super speedmaster props on the TRS. We cut the SSM prop diamator down to (I think) 15 3/4 or 16 inch to fit TRS. It was 7 mph over any other prop out there at the time. The problem was the prop gave so much lift in bow and stern that we were stating to surface ride the TRS. Due to the TRS only having one pinion shaft it would vibrate the pinion. So if the drive started to chatter and you slowed down and took it apart it could be fix. If you were going like the hammers of hell and don't feel the chatter you got a big bang ! and the pinion would come through the case. The price you pay to get a couple extra MPH's Some times I would blow two lower units a summer. Years ago I went to a Marage prop and never broke a drive again. Come to think about I got old, slowed down and haven't blown any motors up either.

 

[gripit]

Great thread. I was looking for a TRS manual but the link doesn't seem to work any longer. Does anybody have a link or a PDF?
Thanks

 

[Holy Smokes]

Great thread. I was looking for a TRS manual but the link doesn't seem to work any longer. Does anybody have a link or a PDF?
Thanks

Not really a manual per say, but a complete parts breakdown is always available on Bam's website. Great source of info there.

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=76022

EDIT>>>
I just noticed they DO show a manual available for purchase.
http://www.mercruiserparts.com/Show...&bnbr=0&bdesc=MISCELLANEOUS+PARTS/ACCESSORIES