Benefit in installing M50D-R1 HD internals into an M50D-R1?

[99streetranger]

I have a 3.0 auto, but planning on a manual swap. I will be rebuilding the transmission that I pull either way. I was wondering if it would be any benefit to install the stronger synchros from the HD into the regular R1 trans?

 

[pjtoledo]

check the gear ratios first.
the transmissions for 3.0 & 2.3 have lower ratios than 4.0 trannies in the lower gears.

 

[sgtsandman]

The gear ratios are different in the HD compared to a regular transmission. I would check the information in the tech section on the gear ratios and make sure they are right for you.

There is probably more information that there as well. I don't remember what makes an HD and HD. So, I can't say if the syncros are stronger or not.

 

[Shran]

There is no benefit to doing that. Nobody has provided conclusive evidence that the HD is stronger so I am very skeptical... the syncros are not a weak point in these transmissions anyway.

Also the rebuild kits and parts for the HD models are extremely expensive and hard to find.

 

[99streetranger]

There is no benefit to doing that. Nobody has provided conclusive evidence that the HD is stronger so I am very skeptical... the syncros are not a weak point in these transmissions anyway.

Also the rebuild kits and parts for the HD models are extremely expensive and hard to find.

Ah okay, just testing the waters right now. I’ll probably just rebuild the R1 like normal.

 

[gw33gp]

There was a point where the 5th gear area was changed to improve oiling to that area. I don't know if that is in the HD only.

 

[Shran]

There was a point where the 5th gear area was changed to improve oiling to that area. I don't know if that is in the HD only.

I can't say either but you do bring up a good point, there were a few M5OD variants. '88 to 90/91ish was the first one, then very early 90's to the mid 90's (reverse cluster redesigned), then for a few years after that where certain gears were cut differently & the shifter was modified, up until '01 or so when the HD variant came out. I haven't played with the newer ones at all so I guess I can't say if the HD was only behind the 4.0 SOHC, and if so, were the internals the same as the 2.3 and 3.0 transmissions, or were those more similar to the units from the late 90's?

All that is probably irrelevant, my advise is pick the gear set you want and buy the rest of the parts based on that. Transmissions that originally were behind 4.0 engines of any year have slightly higher ratio 1st and 2nd gears - 4 cylinder, 2.9 and 3.0 transmissions have lower 1st and 2nd gears.

 

[99streetranger]

I can't say either but you do bring up a good point, there were a few M5OD variants. '88 to 90/91ish was the first one, then very early 90's to the mid 90's (reverse cluster redesigned), then for a few years after that where certain gears were cut differently & the shifter was modified, up until '01 or so when the HD variant came out. I haven't played with the newer ones at all so I guess I can't say if the HD was only behind the 4.0 SOHC, and if so, were the internals the same as the 2.3 and 3.0 transmissions, or were those more similar to the units from the late 90's?

All that is probably irrelevant, my advise is pick the gear set you want and buy the rest of the parts based on that. Transmissions that originally were behind 4.0 engines of any year have slightly higher ratio 1st and 2nd gears - 4 cylinder, 2.9 and 3.0 transmissions have lower 1st and 2nd gears.

So I could technically use the HD gearing in the regular R1? I may be turbocharging down the line and feel like I would run out of gearing with the normal short ratio gears.

 

[sgtsandman]

If the info isn't in the tech section, I would try to find a repair manual for the transmission so as to make sure the parts will fit. You're really going into the weeds on this one and I don't know if anyone here has the yes/no/maybe answers you need.