April of 09 I did the 4-spd transmission swap in my 85 300D. I had the usual vibrations I read about others had with their swaps. tried to raise the trans mount, lower the X mount some, even lowered the center support bearing. been up and down with this thing. tried different transmission mounts, 300D, 240D etc...
Replaced the center support bearing and U-Joint. Just finished up on the rear sub frame and trailing arm replacement. swapped out lower milage trailing arms to eliminate the bearing problem. the R/R seemed to be complaining some. and swapped out a lower milage Diff from another 85. even new axles.
The FW was matched balanced also.
Driving around town, usually in 3rd gear, so the rpm`s drop in the 2000 range +-. so really get the roughness. on the highway around here, the speed is around 50mph, so have to be in 3rd to keep the r`s up.
with the 2:88 diff being higher geared than the 3:07, might be some of the issue. overall Iam happy with the swap. milage has gone up 3mpg on the Hwy.
so as time has gone on now, I have come to the conclusion it could be in the transmission. 1st and second is smooth, even running it up to say 3200rpm`s.
the 3rd there is a roughness in the drive train almost like a U-Joint. best I can come up with. then 4th also has it until Iam over 2700 to 3000rpm`s.
Iam starting to think maybe 3&4 have an internal problem like a bearing that has enough wear, that it letting the gears drop and not mesh correctly.
so I have another JY 4-spd Iam putting back in today. I pulled everything out on Monday, and yesterday I picked up a Harbor Freight Transmission Jack. the 450lb one with the 4 casters. SKU# 39178. it is Normaly $99, now on sale for $79, and with a 20% off coupon drops another $16 for a total of $69.59.
Have any of you used this Jack? Iam hoping today it all goes back in w/o any new words invented
. I will report back as how well it goes back in.
When I did the swap, I pulled the engine and trans as a unit. so installing the 4-spd was a snap on the ground. I have pulled a few at PNP, just not replaced one laying on the ground.
Charlie