Manual Transmission Options? - PeachParts Mercedes-Benz Forum

Gordo · #1 12-13-2022, 11:23 PM

I have been through 4 manual gearboxes (and at least 8 clutches), in the last 250k in my manual swapped 300tdt. 3 iron boxes and one getrag box. I love the car, but I am getting sick of all the transmission/clutch issues.

Has anyone had success with a Toyota w56? I know there are adapter plates for swapping the 617 into a Toyota P/U, but what about putting the Toyota transmission in the w123? I think the Toyota clutch will hold up better too (bigger and heavier duty).

What about the Volvo M46? It looks like I could possibly use the bell housing from the Mercedes iron box and adapt it to the Volvo transmission. I could also move the shifter since it has a linkage outside the gearbox. The trouble is that I would still be stuck with the weak Mercedes clutch, and I don't know if the input shaft is the right length.

What about the Ford T5? Has anyone used this in a W123?

Thanks for your help.

oldsinner111 · #2 12-14-2022, 08:45 AM

check thrust bearing in engine, and if rear end is to tall. seen several MGB Midgets with problem. Crankshaft would move forward, slipping the clutch

BirthdayBenz · #3 12-14-2022, 11:40 AM

There's always the BMW GS637DZ option.

https://dieselpumpuk.com/products/om617-to-bmw-6-speed-37dz-adapter-kit

This is the 6 speed transmission I have in my W123 .

Diesel911 · #4 12-14-2022, 02:26 PM

Quote:

Originally Posted by Gordo

I have been through 4 manual gearboxes (and at least 8 clutches), in the last 250k in my manual swapped 300tdt. 3 iron boxes and one getrag box. I love the car, but I am getting sick of all the transmission/clutch issues.

Has anyone had success with a Toyota w56? I know there are adapter plates for swapping the 617 into a Toyota P/U, but what about putting the Toyota transmission in the w123? I think the Toyota clutch will hold up better too (bigger and heavier duty).

What about the Volvo M46? It looks like I could possibly use the bell housing from the Mercedes iron box and adapt it to the Volvo transmission. I could also move the shifter since it has a linkage outside the gearbox. The trouble is that I would still be stuck with the weak Mercedes clutch, and I don't know if the input shaft is the right length.

What about the Ford T5? Has anyone used this in a W123?

Thanks for your help.

This is not a Mercedes but a past girlfriend had a new Ford truck that kept eating transmissions. After the 4th transmission the dealer decided to check the run out of the bell housing and found that it was out of spec.

When the run out was brought within spec the transmission issues disappeared.

I don't know how the dealer corrected the issue but on other diesel engines you remove the alinement pin and move the bell housing around till the dial indicator run out shows it is within spec and torque it and re-check it and drill it for oversized alignment pins while the bell housing is bolted and torqued down.

Gordo · #5 12-14-2022, 05:59 PM

Quote:

Originally Posted by oldsinner111

check thrust bearing in engine, and if rear end is to tall. seen several MGB Midgets with problem. Crankshaft would move forward, slipping the clutch

The clutch is not failing from wear, so I don't think slippage is the issue. It is the springs in the hub that break, then end up between the pressure plate and the disk. The clutch that is in it now has outlasted the other ones. It is made by Luk. The Sachs disk seems a bit less durable. Although I have had both fail... Always the same failure.

Gordo · #6 12-14-2022, 06:22 PM

Quote:

Originally Posted by Diesel911

This is not a Mercedes but a past girlfriend had a new Ford truck that kept eating transmissions. After the 4th transmission the dealer decided to check the run out of the bell housing and found that it was out of spec.

When the run out was brought within spec the transmission issues disappeared.

I don't know how the dealer corrected the issue but on other diesel engines, you remove the alinement pin and move the bell housing around till the dial indicator run out shows it is within spec and torque it and re-check it and drill it for oversized alignment pins while the bell housing is bolted and torqued down.

That is an interesting thought. I am not sure how to set up a dial indicator to measure runout inside the bell housing since it would need to be put assembled to simulate running conditions Plus IIRC the Benz bell housing has a ridge on it that fits the adapter plate on the back of the engine. I don't see how it could be out of alignment.

I assumed the issue is the combination of the bigger 300 turbo motor, the heavier station wagon full of stuff (sometimes pulling a tailor), and living at the top of a really steep hill. I am running a 240 flywheel. It is a little lighter than the gray market 300 (rare as hen's teeth) flywheel.

nastala · #7 12-19-2022, 08:22 AM

Quote:

Originally Posted by Gordo

I have been through 4 manual gearboxes (and at least 8 clutches), in the last 250k in my manual swapped 300tdt. 3 iron boxes and one getrag box. I love the car, but I am getting sick of all the transmission/clutch issues.

Has anyone had success with a Toyota w56? I know there are adapter plates for swapping the 617 into a Toyota P/U, but what about putting the Toyota transmission in the w123? I think the Toyota clutch will hold up better too (bigger and heavier duty).

What about the Volvo M46? It looks like I could possibly use the bell housing from the Mercedes iron box and adapt it to the Volvo transmission. I could also move the shifter since it has a linkage outside the gearbox. The trouble is that I would still be stuck with the weak Mercedes clutch, and I don't know if the input shaft is the right length.

What about the Ford T5? Has anyone used this in a W123?

Thanks for your help.

I wouldn't consider the M46, it may have issues handling the torque. I know they have issues in turbo redblocks making power (300+).
Though going through that many transmissions and clutches is certainly a sign of something

ROLLGUY · #8 12-19-2022, 07:01 PM

An adapter for a Jeep transmission (AX-5 2wd and AX-15 4wd) to a 617 is available several places. Both use the Jeep flywheel and clutch, so they are plenty strong. I am not sure how the shifter would line up, but I am sure shifter relocation setups are available.