missing a gear?
 

the 87 190e 2.6 i bought recently seems to be running awful high rpms at highway speed (3000 @ 62mph) is the over drive not engaging - is there a lock up torque converter on the car? i haven't got any manuals on the car yet
(last week i did notice the atf was low added 2 qts of redline synthetic) i only feel 2 shift points when in drive, should there be 3.

That's what 300Es and 300SEs with similar engines and transmissions run. 62mph at 3000rpm is too relaxed for 3rd gear either.

Sixto
95 S420
87 300SDL

I'm pretty sure the 190 has the same transmission as the 124 series- there isn't an overdrive- it's 4-speed. Since you have an earlier model your transmission probably starts in 2nd, hence only 2 shifts: 2-3 & 3-4.
Mine I think runs around 3000-3500rpm at 70-80ish.

Exactly. Your top gear is 1:1, and it starts in 2nd gear.

The speedometer gearing is set up for the 849 revs/mile of the OE 185/65R-15 tires and the axle ratio is 3.27:1, so revs at 60 are 849 x 3.27 = 2776.

Tires with a different revs/mile spec will not effect this relationship, but they will impact speedometer accuracy, and as previously stated, the auto trans starts in second gear unless you floor the throttle. Fourth (top) gear is direct and there is no "overdrive".

Duke

These revs would be applicable with a manual transmission with the rear wheels directly coupled to the engine.

However, in the case of an automatic, with a fluid coupling, the actual rpm at 60 mph is going to be 200-300 higher than 2776, and, hence the posted 3000 rpm figure.

thanks guys
 

thanks to all you guys you're helping me learn about this car alot :)

It's actually a torque converter. A fluid coupling does not multiply torque. The original four-speed GM Hydramatics from the late forties to sixities had a fluid coupling rather than a torque converter.

Under cruise load a non-lockup torque converter will have some slippage, but I doubt if it's more than about 3 percent, which would only be about 100 revs at 3000. Plus there's some inherent error in the speedo gearing and the speedo and tach head calibration and our ability to accurately interpolate between the hash marks.

If the tach/speedo readings are within three percent of the calculation, then it can be considered okay.

Duke

A torque converter is a fluid coupling, by definition.



The starter of the thread already posted that he is running 3000 rpm @62 mph. This is about 200 rpm more than the calculated 2776 rpm from a rigid coupling. A high stall torque converter has considerably more than 3% slippage.

No, a fluid coupling and torque converter are different animals. A fluid coupling provides no torque multiplication. A torque converter does. If you've been around long enough to understand the original GM Hydramatic you understand this!

Production cars do not use "high stall" torque converters. Drag racing cars and hot rods only. High stall converters yield very poor fuel economy.

Duke

I don't want to tell you how long I've "been around". However, I will tell you, again, that a torque converter is a fluid coupling.



My 300SD uses a high stall torque converter.
My 300 SDL uses a high stall torque converter.
The 190 mentioned above uses a high stall torque converter.

End of discussion.

Maybe if torque converter was spelled out to be fluid coupling with torque multiplication it would be more clear.

Sixto
95 S420
87 300SDL

how many MB forum members does it take to change a lightbulb...? :)

Wow
 

I didn't mean to open such a can of worms - thanks again guys!!
info and entertainment who 'da thunk it!