Close Ratio Gear Box: 265/5

[BrewKaiser]

Synchros on my 262 4-speed are getting tired. I'm planning to either rebuild or replace next year. The engine is a 3.5L M90 with DCOE 40s. Plenty of power down low and up high. One option offered is swapping my existing 4 speed 262 with a close ratio 5 speed (265/5 I believe) with the dogleg 1st gear.

For roughly $2500 I can have the existing rebuilt or for $7500 I can have the "sportier" 5 speed.

My rear main seal has a slight leak so all this work can be sorted at once next year late winter or early spring. Apparently the bell housing is also not true to the model so we would correct this as well.

Interested in what the experts here think.

 

[Rek]

Is that what they cost now? Phew!

 

[Stevehose]

I’m no expert but with all that power I would think the 5spd overdrive is the way to go unless you like shifting a lot

 

[Ohmess]

I have a closed ratio 5 speed mated to an M90 in my 79 635csi. Very nice combination.

 

[BrewKaiser]

I have a closed ratio 5 speed mated to an M90 in my 79 635csi. Very nice combination.

What LSD ratio are you running? Been discussing with another member on what ratio to run. My current LSD is 3.64:1.

@Stevehose part of my interest is the reduction in the length of gears for more driving engagement.

 

[Ohmess]

The 635csi came stock with a 3.07 lsd. Very nice fit for that engine/transmission. You will not be happy with a 3:64

 

[sfdon]

For 1200.00 I will ship you 2 decent 4 speeds with warranty.

For 1300.00 I will ship you an inspected, resealed 4 speed with new bearings from Pete’s Gear Shop with warranty

For 4500.00 I will ship you a resealed and inspected 265/5 with new output bearing from Pete’s Gear Shop with warranty

 

[sfdon]

Only diffs go well with the 265/5 in my opinion

The 3.07 and the 3.25

 

[BrewKaiser]

Thanks Don.

I'm working with Stuart Krum, who would source and rebuild. It's at his suggestion that I consider the 265/5 instead of rebuilding the 262. I'll keep your offer in mind as that's certainly attractive.

Appreciate the feedback on the diff. This is good to know. Any pros/cons to 3.07 vs 3.25 I should consider with my engine? I'm trying to find the balance between sportier feel and driving engagement. If I understand the LSD correctly, the net effect of the lower LSD ratio is that even at a 1:1 ratio, 5th gear will feel more like an OD (say 65 mph at 3000 rpm). Currently, I find the majority of my driving can be done in 3rd when driving spiritedly.

When I green light this project next year, it will be a good opportunity to look at the drive-train as a whole in terms of maintenance and fit.

I love the picture of your treasure trove of transmissions.

 

[Pittraider18]

Only diffs go well with the 265/5 in my opinion

The 3.07 and the 3.25

Need to add this to my list of parts to acquire. Rear Diff Re-Gear parts for the 5spd swap.

 

[2000CS]

Don, do I notice correctly that you are in dire need of 4 speed ZFs to fill out those gaps on your shelf?
I happen to like how those double pivot shift forks work.