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1998 s420l gearbox issue

867 views 2 replies 2 participants last post by  andni 
#1 ·
Cl420/s420 engine and transmission swap

Hi!

I've had this beautiful 1998 s420l since 2003. The gearbox is completly destroyed and for about a year now I've been looking for a new one. Recently another option presented itself, but with my limited knowledge I don't know A if it even is practical and B the approximate cost.

I have the possibility of purchashing a cl420 for a very reasonable price, that car has been through an accident and, the right front passenger door and a few other places has got scratches and a few other beauty problems. This car has got fewer mileage than the one I currently have. (Mine is aboute 175000km and this one around 150000km)

My question is if it is possible to switch the engine and the transmission from the cl420 to the s420? And if thats the case, approximate cost/hours to do so?

Thanks in advance!
 
#2 ·
Welcome to the forum,

Fill out your profile, and let us know want country you reside in!

To answer your question, A shop can do the swap in six hours or less. It takes me about that time to do a swap at home with no air tools.

I know you have limited knowledge, but they are identical mechanically, but I would use a 98 or 99 as the TCM(transmission Computer) may have issues with a 96 & 97.

If your donor is "working", I would install a rebuilt torque converter made by CVC with Sonnax updates. CVC is the name of the company who re-manufactures them, and sonnax makes some updates for the torque converter that help people in cold weather climates. The reason to change the torque converter is it contains frictions(clutches) that wear out. If the opportunity opens itself to replace the transmission, replace the engine. I would change the torque converter over 130,000Km. I would replace the front and rear seal of the transmission. Now, I would inspect the outside of the shaft of the donor transmission torque converter. The shaft should not have deep scar abound the shaft as that indicates bearings are worn in the transmission, and you may have issues later on...

In the USA these transmissions are common, but is really wrong with yours?

Martin
 
#3 ·
Thank you for the reply Martin!

The issue with the gearbox is the "typical" bushing problem with the 722.6 transmissions were the lack of lubrication causes friction and heat which results in a breakdown of the transmission. At least thats what I remember from what my mechanic told me, that is if I understood him correctly.

I'm glad to hear that it should be a relatively easy fit. As many people on this part of the forum already knows, the w140 is really a one of a kind. Never driven anything even close to the feel of it. It's more like being in a yacht than in a car, lol. By the way I've got the azurit blue with blue leather, everything stock. Besides the transmission it runs as smoothly as day one.

In Sweden parts are hard to come by and ordering outside of the eu feels a bit risky, I'm not just refering to being ripped off but It's hard to tell the quality as well. Do you know of a good retailer in the eu?
 
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