SL 320 (R129) Transmission problem!

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AKS

New Member
Joined
Sep 28, 2017
Messages
1
Location
London
Car
Mercedes-Benz SL320
Hi there - I am the proud owner of a 1994 Sl320 which has run perfectly since purchasing it 15 months ago, it has now developed a problem with the transmission. Struggles to change up gear, holds in low gear and the engine revs extremely high even in low gear.

I am told (being not mechanically minded) that it is a problem with the back-box (the 5th gear overdrive) on the 4 speed transmission that this model was fitted with. They are apparently now impossible to get hold of and a second hand one has to be sourced- there is only 1 the garage has found at £1,500 , plus fitting will look like £2,500 to complete the work.

I am interested to see what any fellow R129 owners would do- I do love the car (it even came with my initials on the number plate!!) and it is currently sitting with 95,000 miles and is pretty immaculate inside and out (Full service history, all the stamps and original docuemnts, 3 owners) .. but I only paid £6,000 for the car in the first place and I need to seriously weigh up if I now spend £2,500 on it is it worth it ! OR do I just sell it and cut my losses??

Any thoughts would be appreciate!
 
Hi there - I am the proud owner of a 1994 Sl320 which has run perfectly since purchasing it 15 months ago, it has now developed a problem with the transmission. Struggles to change up gear, holds in low gear and the engine revs extremely high even in low gear.

I am told (being not mechanically minded) that it is a problem with the back-box (the 5th gear overdrive) on the 4 speed transmission that this model was fitted with. They are apparently now impossible to get hold of and a second hand one has to be sourced- there is only 1 the garage has found at £1,500 , plus fitting will look like £2,500 to complete the work.

I am interested to see what any fellow R129 owners would do- I do love the car (it even came with my initials on the number plate!!) and it is currently sitting with 95,000 miles and is pretty immaculate inside and out (Full service history, all the stamps and original docuemnts, 3 owners) .. but I only paid £6,000 for the car in the first place and I need to seriously weigh up if I now spend £2,500 on it is it worth it ! OR do I just sell it and cut my losses??

Any thoughts would be appreciate!
So, yours is the 5 speed box. I imagine it's the same one as mine, the 722.5.

If so, I cannot see how the problems you describe can be attributed to the back box. That is just for 4/5th changes.

Who have you consulted about this? You're in London. If SW, try Steve Redfearn in SW19. There are others too. I'm sure this board will make some recommendations.

My 722.5 was recently rebuilt be Mackie Transmissions in Glasgow. It works like new now except for a slight issue with upchanges from 4th to 5th under heavy acceleration. Even the, a brief easing up on the throttle brings a smooth change to 5th. So, overall, well pleased. The cost, about £2500 but that was for an "as new" gearbox.

In your shoes, I'd be looking for someone with experience of that car and the 722.5 box.

Also, I'd be looking at the vacuum connections to the box and the cable between throttle and box.

Good hunting.

RayH
PS: Oh, by the way, if an SL is "pretty immaculate inside and out", then some investment is surely justifiable to keep it in tip top condition.
 
Is the fluid level correct? Has the fluid ever been changed? If not, or if it's more than say 75,000 miles old, get it changed and get it done properly.

A surprising number of problems are down to incorrect fluid level or old fluid.
 

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