Does anyone know what it would take to replace a merctrans with a borg-warner transmission? Would the motor need to be moved? What about the bellhousing?
If the boat is solid and passes a thorough moisture meter test, you will be fine.
Being a 1988, it will be fitted with Borg Warner trannies (last year for the small MercTrans was 1982) As long as the drive is in good working order, the TRS is far superior over the Bravo drive. Persoanally, I'm a fan of TRS boats, they can be bought reasonably and if you have the want for bigger power, a bolt-on solution is readily available with the Konrad 540 TRS conversion system. Also, Konrad has recently introduced a shorty lower unit (Konrad's "X-Factor")
As mentioned above, the TRS was a rugged unit for what it was designed for and Merc did not discontinue the TRS because of failures, it was discontinued because it was expensive.
The easiest way and least expensive, to swap to a Borg Warner would be with used components gathered from a TRS installation. Find a tranny with TRS tailstock, bellhousing and drive plate. You will also need a remote tranny cooler as the MercTrans cooler was internal.
To swap from the MercTrans to a Borg Warner, the motor needs to be moved forward about a foot depending on if you are swapping to a Borg 71C or 72C (72C is 15/16 longer)
You will need the transmission style bellhousing as the MercTrans incorporates the bellhousing into the case. The TRS tailstock has "ears" on it that will be your new rear motor mount, your existing inner transom plate will work with this mount.
The female spline input shaft on your drive will need to be swapped out to a TRS Borg male input shaft. Other than installing a tranny cooler (inline afer the oil cooler) you will be done.
It's a pretty simple conversion if you've got the room to move the motor forward. If you do not have that much room, Konrad has a custom tailshaft for the Borg Warner than can save you about 4"
Last edited by Biggus; 04-13-2007 at 07:09 AM.
I have a Merc Trans in front of a Trs in the Donzi. Yes, it's a 1982. It was seized up when I bought the boat (trans), so I had it pulled and rebuilt. The guy who worked on it has been working on drives since Christ was a carpenter. He put an extra clutch in the tranny and said it would be good to 650 hp. As far as drives, he is a big fan of Trs. He was ranting about the new drives they come out that you need a transmission for, he said, "What do you have when you take the shift mechanism out of a Bravo type drive? A Trs drive!"
I was going to have him take the drive apart before I put it in the water, but he doesn't work cheap, so he checked the fluid, turned the drive by hand, then suggested putting new u joint in, new drive oil, and calling it good. He said the Trs is a tough, tough drive.
Btw, the Merc tran is a Ford transmission with only one forward gear. I can't remember if it was based on the FMX transmission, or the C-6. Anyway, it uses Ford parts.
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