auto trans help

[CK25]

I have a 1978 CJ7 it has an automatic Transmission 400 i think. It makes whinning noises when it gets to around 40-45mph. I drained all Transmission fluid and changed the filter put in the recommended type and amount but it still makes this noise. There are no leaks in the system. What could cause this noise?

 

[Torxhead]

Another possibility of that noise could be the Transfer Case . There are a few guys on this forum with that system in their rigs and could possibly help you out.

 

[jeepboy45]

It sounds like you probably have the same version I do on my 79 CJ7 . I have the AMC 304 , GM Turbo 400 mated to a QuadraTrac fulltime 4wd Transfer Case .

I just had my GM Turbo 400 thoroughly rebuilt about 6 months ago. Right beforehand it was slipping HORRIBLY, requiring me to run up the RPM's to get it to partially slide into gear. It whined at that point--- basically the point of death for my tranny... But it was NOT at a given mph, just whining like heck as it slipped badly...

Your T case requires special fluid unless it has undergone the "milemarker" conversion to a 2x4 from full time 4wd. I would check to see if it is full. There are several plugs on this TC. You need to get the shop manual and determine which is the drain plug and which is the "fill-to" plug. If you have the optional reduction unit on the TC, it also has fill plugs. Too low fluid could cause a whine, and ultimately a "bang-bang" sound as the worn out chain slips on the large gears.

I'd also try and rule out worn out U-joints on your driveshaft. They can cause a whine, especially at a given mph.

Does it whine the same at 45 mph whether you are in "drive" (presumably in 3rd gear at that speed) or if you pull it down into 2nd gear?

Try and rule out every variable you can.

good luck
brian

 

[CK25]

Thank you. I did not know about the reduction unit had a fill also(first timer with this set up). I filled that and it is still making the noise so im just gonna pull it and do a rebuild and be happy. The Transmission and u joints are good(new U-joints)