WallyP

One of our customers replaced an earlier five-speed with a RoW G28.10 box. After installation, he discovered that the shift lever was centered in the 4-5 plane, causing some difficulty in racing shifts. He asked if there was any adjustment to move the centering position to the 2-3 plane.

I answered:

"From the service info by year booklet for the 1986 model:
Manual Transmission G 28 .10 (R . o . W.) and
G 28 .11 (USA and Canada)
Various changes have been made in the area of final drive and rear transmission cover.
In addition, shift operation in the transmission has been revised.
In neutral position the shift lever is now in shift plane 2 - 3 (formerly 4 - 5).

Shift Operation Spring
The formerly built M 28 .10 and 11 transmissions had a spring design which guided the shift
lever into shift planes 4 - 5, the "high" gears .
The new spring design (arrow) now holds the shift lever firmly in shift plane 2 - 3.
The spring force must now be overcome to a) shift into 1 - R plane or b) 4 - 5 plane.

This tells us that if your G28.10 came out of an '85, it is spring-loaded to the 4-5 position. If it came out of an '86, it is spring-loaded to the 2-3 position. I don't think that you can adjust it - but I might be wrong. The Factory Workshop Manual shows the '85 adjustment on Page 34-217 thru 218, and the '86 and '87-up adjustment on Page 34-218a thru 218c. The drawing for the '85 and '86 adjustments look identical to casual inspection, while the '87 drawing shows minor changes in the upper right corner. I don't have a clue as to whether the '85 box can be adjusted to the '86 procedure.

If not, you MIGHT be able to change the parts to make it an '86 transmission, but I don't know that. I do think that it would require removal and disassembly to do so, if it can be done."

Does anyone have any additional info?

a4sfed928

I think all you have to do is change the spring to the updated one

Vilhuer

Spring was changed to achieve 2-3 neutral position. Older style spring can not be adjusted to 2-3. Using later style spring should allow it.

Spring can be changed without removing gearbox internals but its difficult in '85 gearbox as its kept in place by circlip. Did it once and would do it again if I have to but it not fun job. Box has to come down for it.

mark kibort

Maybe im missing something, but the coupler in the rear can be rotated for shift position and then the ball cup up front, can be loosened or tightened to change the fore and aft position. basically, totally adjustable.

edit: there are two springs that the shift lever can fight against. reverse and 1st gear path, and with my S4 gear box, a very weak position spring keeping the shifter in the 4-5 gear path range. If we are talking racing shifts, are you really talking about the overall shift pattern position? If so, the rear coupler can position so that the gears are where you want them to be.

WallyP

Thanks, Guys.

Hilton

Mark, he means the gearbox position the lever is sprung to go to when in neutral if you let it go - not adjustable, unlike the physical position of the lever which can be adjusted at the rear coupler as you say.

Your S4 box sounds like one of the springs is broken? My '87 has a weak spring keeping it in 2/3 instead of 4/5, and a stronger spring to overcome to get to 1/R. If I shift to neutral and release, it goes to 2/3.

My 89 S4 also springs to 2/3 when in neutral - slightly firmer spring than the '87, although that could just be a result of the short-shifter reducing the leverage I exert against the spring, making it feel heavier-sprung.

Mike Frye

Wally, I was looking to upgrade to the newer spring when I had to replace the shift spring and reverse lockout spring in my '85. I found (from Erkka, I think) that there are two parts that would need to be upgraded. First would be the newer style spring, but the second is the pre-selector lever that rides on the spring.

(pics from the 'Manual Transmission for 8-cyl Model Series.pdf') from the transmission folder in Jim's CD set.




Replacing the spring can be done by just dropping the trans and removing the top cover, but the roller would be more involved.

I ended up not doing this and leaving the adjustment screw so that it's on the loose side so it doesn't flex as much when it's in pulled over into the 1/R plane. This removes some of the pre-load so that the lever can rest in either 2/3 or 4/5 and it also means there's less stress on the spring when it's in 1/R.

(I've also stopped leaving it in 1st when I'm at a light, now that I know that spring is prone to snapping)