Background: After extensive white paper towel testing, I finally was able to prove to myself that a substantial transmission fluid leak which took place while the car was parked for winter storage emanated from the gear selector shaft (aka Range Selector Control Shaft) seal located midway on the driver side of the transmission housing.
The shaft rotates within the circumference of this radial seal every time you move the center console mounted gear selector. Vehicle service documentation states my car’s transmission was overhauled for front pump & seal replacement in 2008 just prior to my ownership, but no evidence confirmed whether or not this particular seal was also replaced at that time.
The bottom-line: The selector shaft seal needed replacement now.
I ordered two new OE selector shaft seals (p/n# 006 997 01 47) along with various replacement orings & sealing rings for other transmission-attached parts whose condition would be inspected.
I would also install a First Gear Start valve body since the car would already be up on stands with the transmission pan removed.
An exhaustive web-search found only one semi-informative thread on this seal replacement subject. It was a seven step procedure for a pedestrian Benz 722.3xx tranny. The author alleged a 1.5 hour ability to replace the seal in situ without lowering the transmission. Oh happy day!
…Unhappy day. The procedure is not applicable to the 500E. The procedure became a no-go at step 6 of 7. Tranny tunnel clearance is too tightly constrained for selector shaft removal. The shaft butts against the tunnel before it can exit its tranny housing bore.
I then took more time to research the use of some specialized seal-pulling tools to remove the seal with the shaft in place. Nope, still not gonna work in this particular situation. If even fortunate enough to remove the old seal with the shaft in place, it is still highly improbable to successfully drive-in & seat a new seal because of space limitations.
Leading into this project, I always knew that the proper procedure would be a whole lot of FSM 27-600 Removing and Installing Transmission, plus some other pre & post-requisite procedures. But for just one little seal, I really didn’t want to go thru all that work required to lower the tranny down the few necessary inches for the selector shaft to clear the tunnel constraint. My Master Mechanic/Doctor of Motors dad used to do foreign trannies all the time with his eyes closed. I would watch & help with this intimidating endeavor. I learned how to properly do aspects of transmission work without necessarily liking to do it. I hadn’t done any in a real long time… Therefore I had a severe avoidance complex.
There’s got to be a short cut!
So I further procrastinated the inevitable until an epiphany occurred during a trip to the junk yard. I saw cars with floor & tranny tunnel access hole plugs! What’s the chances the 500E has one directly inline with the selector shaft? And if not, maybe I can drill/cut out an access hole thru the tunnel area directly opposite from the selector shaft which will then allow me to pull said shaft clear from the tranny housing? Racers do this stuff all the time. The access hole would be drill/cut to precisely mate with an OEM floor plug liberated from a donor Benz. Replace shaft seal, re-insert shaft, weatherize & plug access hole for a factory look, replace carpet. Done. No other removal, replacement, re-torqueing, readjusting or unintended debasing of anything else required. I like this kind of work. Yay!
Boo. Location, location, location. An access hole is a neat idea, but not applicable in this particular situation. No short cut. Got to do it the right way.
The right way is a long way.
(to be continued)
The shaft rotates within the circumference of this radial seal every time you move the center console mounted gear selector. Vehicle service documentation states my car’s transmission was overhauled for front pump & seal replacement in 2008 just prior to my ownership, but no evidence confirmed whether or not this particular seal was also replaced at that time.
The bottom-line: The selector shaft seal needed replacement now.
I ordered two new OE selector shaft seals (p/n# 006 997 01 47) along with various replacement orings & sealing rings for other transmission-attached parts whose condition would be inspected.
I would also install a First Gear Start valve body since the car would already be up on stands with the transmission pan removed.
An exhaustive web-search found only one semi-informative thread on this seal replacement subject. It was a seven step procedure for a pedestrian Benz 722.3xx tranny. The author alleged a 1.5 hour ability to replace the seal in situ without lowering the transmission. Oh happy day!
…Unhappy day. The procedure is not applicable to the 500E. The procedure became a no-go at step 6 of 7. Tranny tunnel clearance is too tightly constrained for selector shaft removal. The shaft butts against the tunnel before it can exit its tranny housing bore.
I then took more time to research the use of some specialized seal-pulling tools to remove the seal with the shaft in place. Nope, still not gonna work in this particular situation. If even fortunate enough to remove the old seal with the shaft in place, it is still highly improbable to successfully drive-in & seat a new seal because of space limitations.
Leading into this project, I always knew that the proper procedure would be a whole lot of FSM 27-600 Removing and Installing Transmission, plus some other pre & post-requisite procedures. But for just one little seal, I really didn’t want to go thru all that work required to lower the tranny down the few necessary inches for the selector shaft to clear the tunnel constraint. My Master Mechanic/Doctor of Motors dad used to do foreign trannies all the time with his eyes closed. I would watch & help with this intimidating endeavor. I learned how to properly do aspects of transmission work without necessarily liking to do it. I hadn’t done any in a real long time… Therefore I had a severe avoidance complex.
There’s got to be a short cut!
So I further procrastinated the inevitable until an epiphany occurred during a trip to the junk yard. I saw cars with floor & tranny tunnel access hole plugs! What’s the chances the 500E has one directly inline with the selector shaft? And if not, maybe I can drill/cut out an access hole thru the tunnel area directly opposite from the selector shaft which will then allow me to pull said shaft clear from the tranny housing? Racers do this stuff all the time. The access hole would be drill/cut to precisely mate with an OEM floor plug liberated from a donor Benz. Replace shaft seal, re-insert shaft, weatherize & plug access hole for a factory look, replace carpet. Done. No other removal, replacement, re-torqueing, readjusting or unintended debasing of anything else required. I like this kind of work. Yay!
Boo. Location, location, location. An access hole is a neat idea, but not applicable in this particular situation. No short cut. Got to do it the right way.
The right way is a long way.
(to be continued)
.
