JD 450C lost reverse

Hartlyboy

Member
My 1975 450C doesn't get a lot of hours put on it at the farm and up until today has performed pretty reliably. I down shifted to 1st gear using the clutch and then put the select lever at L to give the maximum gearing to push over a rotted stump. That was done easily but when I put the lever back to R to back up, nothing happened and trying to put it in a higher gear was difficult. Maybe I lost a clutch and reverse at the same time? It moved backward slowly when I revved the engine some but now won't even do that.

I'm trying to figure out possibilities and am looking online but I wondered if any of you have run across something like this. The L and H and N positions seem to work OK and it steers as well as it ever did -just no reverse.

There is an opening in floorplate by the clutch with what looks like a large bolt head. That seems to be about the extent of the possible adjustments I can make [if it is an adjustment] without getting into some serious disassembly. Yes the fluid level is good in the tranny and the linkage seems OK. Any ideas?
 

It sounds like it might have a problem with the reverse clutch, but that is just a maybe at this point. Diagnosis first, do not just start turning things. Get the correct John Deere technical manual for it and go through the clutch and linkage adjustments. Check/do all of them in the order given in the manual. Several are related to, and affected by, other adjustments. Then do the pressure checks.
 
You can access YT's archives. I've submitted instructions to adjust and check HLR problems over the years. Always pressure test before cranking
down on anything. Your problem could be as simple as a broken roll pin if it happened quickly.
 
(quoted from post at 10:54:22 09/15/22) You can access YT's archives. I've submitted instructions to adjust and check HLR problems over the years. Always pressure test before cranking
down on anything. Your problem could be as simple as a broken roll pin if it happened quickly.

Well, I've done the easy stuff -checked the linkage, changed the HLR filter and still have no reaction. I'm beginning to suspect the pump since , after sitting for a day it will move in reverse on start up for a few yards, but weakly.
I'm too old and creaky to do a lot of wrench pulling and recognize your sound advice to do adjustments and pressure tests before getting too radical. I'll bring in a heavy equipment service and have that done -but if the pump does show weak output, can it be replaced without splitting the tractor or pulling the motor? Can it be accessed and replaced by taking off the top plates on the tranny ?
 

The pump is mounted on the front cover of the transmission, slid on over, and driven by, the front drive shaft (input shaft from the engine clutch). Engine has to be removed. Do you have John Deere technical manual TM1102? It might help you.

Here is one discussion Roy gave info in, there are others.
 

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